The human body can tolerate relatively long. Problems in physics with elements of astronomy. How long can we live without oxygen

The human body is very delicate. Without additional protection, it can only function in a narrow temperature range and at a certain pressure. It must constantly receive water and nutrients. It will not survive a fall from more than a few meters. How much can the human body withstand? When our body is threatened with death? Fullpiccha brings to your attention a unique overview of the facts about the limits of the survival of the human body.

8 PHOTOS

The material was prepared with the support of the Docplanner service, thanks to which you will quickly find the best medical institutions in St. Petersburg - for example, the dzhanelidze ambulance research institute.

1. Body temperature.

Limits of survival: body temperature can vary from + 20 ° C to + 41 ° C.

Conclusions: usually our temperature ranges from 35.8 to 37.3 ° C. This temperature regime of the body ensures the smooth functioning of all organs. Temperatures above 41°C cause significant fluid loss, dehydration and organ damage. At temperatures below 20 ° C, blood flow stops.

The human body temperature is different from the ambient temperature. A person can live in an environment at temperatures from -40 to +60 ° C. It is interesting that a decrease in temperature is just as dangerous as its increase. At 35°C, our motor functions begin to deteriorate, at 33°C we begin to lose our bearings, and at 30°C we lose consciousness. A body temperature of 20°C is the limit below which the heart stops beating and the person dies. However, medicine knows the case when it was possible to save a man whose body temperature was only 13 ° C. (Photo: David Martín / flickr.com).

2. The efficiency of the heart.

Limits of survival: from 40 to 226 beats per minute.

Conclusions: a low heart rate leads to a decrease in blood pressure and loss of consciousness; too high a heart rate leads to a heart attack and death.

The heart must constantly pump blood and distribute it throughout the body. If the heart stops working, brain death occurs. The pulse is a wave of pressure induced by the release of blood from the left ventricle into the aorta, from where it is distributed by arteries throughout the body.

Interestingly, the "life" of the heart in most mammals averages 1,000,000,000 beats, while a healthy human heart performs three times as many beats in its entire life. A healthy adult heart beats 100,000 times a day. In professional athletes, the resting heart rate is often as low as 40 beats per minute. The length of all blood vessels in the human body, when connected, is 100,000 km, which is two and a half times longer than the length of the Earth's equator.

Did you know that the total capacity of the human heart over 80 years of human life is so great that it could pull a steam locomotive up the highest mountain in Europe - Mont Blanc (4810 m above sea level)? (Photo: Jo Christian Oterhals/flickr.com).

3. Overloading the brain with information.

Limits of survival: each person is individual.

Conclusions: information overload leads to the fact that the human brain falls into a state of depression and ceases to function properly. The person is confused, begins to carry nonsense, sometimes loses consciousness, and after the symptoms disappear, he does not remember anything. Prolonged overload of the brain can lead to mental illness.

On average, the human brain can store as much information as 20,000 average dictionaries contain. However, even such an efficient organ can overheat due to an excess of information.

Interestingly, the shock resulting from extreme irritation of the nervous system can lead to a state of stupor (stupor), while the person loses control of himself: he can suddenly exit, become aggressive, talk nonsense and behave unpredictably.

Did you know that the total length of nerve fibers in the brain is between 150,000 and 180,000 km? (Photo: Zombola Photography/flickr.com).

4. Noise level.

Survival limits: 190 decibels.

Conclusions: at a noise level of 160 decibels, eardrums begin to burst in people. More intense sounds can damage other organs, particularly the lungs. The pressure wave ruptures the lungs, causing air to enter the bloodstream. This, in turn, leads to blockage of the blood vessels (emboli), which causes shock, myocardial infarction, and eventually death.

Typically, the range of noise we experience ranges from 20 decibels (whispers) to 120 decibels (airplanes taking off). Anything above this limit becomes painful for us. Interesting: being in a noisy environment is harmful to a person, reduces his efficiency and distracts. A person is not able to get used to loud sounds.

Did you know that loud or unpleasant sounds are still used, unfortunately, during the interrogation of prisoners of war, as well as in the training of special services soldiers? (Photo: Leanne Boulton/flickr.com).

5. The amount of blood in the body.

Limits of survival: loss of 3 liters of blood, that is, 40-50 percent of the total in the body.

Conclusions: lack of blood leads to a slowdown in the heart, because it has nothing to pump. The pressure drops so much that the blood can no longer fill the chambers of the heart, which leads to its stop. The brain does not receive oxygen, stops working and dies.

The main task of blood is to distribute oxygen throughout the body, that is, to saturate all organs with oxygen, including the brain. In addition, blood removes carbon dioxide from tissues and carries nutrients throughout the body.

Interesting: the human body contains 4-6 liters of blood (which is 8% of body weight). The loss of 0.5 liters of blood in adults is not dangerous, but when the body lacks 2 liters of blood, there is a great risk to life, in such cases medical attention is needed.

Did you know that other mammals and birds have the same ratio of blood to body weight - 8%? And the record amount of blood lost in a person who still survived was 4.5 liters? (Photo: Tomitheos/flickr.com).

6. Height and depth.

Survival limits: from -18 to 4500 m above sea level.

Conclusions: if a person without training, who does not know the rules, and also without special equipment dives to a depth of more than 18 meters, he is at risk of rupture of the eardrums, damage to the lungs and nose, too high pressure in other organs, loss of consciousness and death from drowning. Whereas at an altitude of more than 4500 meters above sea level, a lack of oxygen in the inhaled air for 6-12 hours can lead to swelling of the lungs and brain. If a person cannot descend to a lower altitude, he will die.

Interesting: an unprepared human body without special equipment can live in a relatively small range of altitudes. Only trained people (divers and climbers) can dive to a depth of more than 18 meters and climb mountains, and even they use special equipment for this - diving cylinders and climbing equipment.

Did you know that the record in one-breath diving belongs to the Italian Umberto Pelizzari - he dived to a depth of 150 m. During the dive, he experienced tremendous pressure: 13 kilograms per square centimeter of the body, that is, about 250 tons for the whole body. (Photo: B℮n/flickr.com).

7. Lack of water.

Survival limits: 7-10 days.

Conclusions: lack of water for a long time (7-10 days) leads to the fact that the blood becomes so thick that it cannot move through the vessels, and the heart is not able to distribute it throughout the body.

Two-thirds of the human body (weight) consists of water, which is necessary for the proper functioning of the body. The kidneys need water to remove toxins from the body, the lungs need water to moisten the air we exhale. Water is also involved in the processes occurring in the cells of our body.

Interesting: when the body lacks about 5 liters of water, a person begins to feel dizzy or faint. With a lack of water in the amount of 10 liters, severe convulsions begin, with a 15-liter deficit of water, a person dies.

Did you know that in the process of breathing we consume about 400 ml of water daily? Not only lack of water can kill us, but its excess. Such a case occurred with one woman from California (USA), who during the competition drank 7.5 liters of water in a short period of time, as a result of which she lost consciousness and died a few hours later. (Photo: Shutterstock).

8. Hunger.

Survival limits: 60 days.

Conclusions: the lack of nutrients affects the functioning of the whole organism. A starving person's heart rate slows down, blood cholesterol levels rise, heart failure and irreversible damage to the liver and kidneys occur. A person exhausted by hunger also has hallucinations, he becomes lethargic and very weak.

A person eats food to provide himself with energy for the work of the whole organism. A healthy, well-nourished person who has access to enough water and is in a friendly environment can survive about 60 days without food.

Interesting: the feeling of hunger usually appears a few hours after the last meal. During the first three days without food, the human body expends energy from the food that was last eaten. Then the liver begins to break down and consume fat from the body. After three weeks, the body begins to burn energy from the muscles and internal organs.

Did you know that the American Amerykanin Charles R. McNabb, who in 2004 starved in prison for 123 days, remained the longest and survived? He drank only water and sometimes a cup of coffee.

Do you know that about 25,000 people die of hunger every day in the world? (Photo: Ruben Chase/flickr.com).

According to the degree of impact of climatic and geographical factors on a person, the existing classification subdivides (conditionally) mountain levels into:

Lowlands - up to 1000 m. Here a person does not experience (compared to the area located at sea level) the negative effect of a lack of oxygen even during hard work;

Middle Mountains - ranging from 1000 to 3000 m. Here, under conditions of rest and moderate activity, no significant changes occur in the body of a healthy person, since the body easily compensates for the lack of oxygen;

Highlands - over 3000 m. These heights are characterized by the fact that even at rest in the body of a healthy person, a complex of changes caused by oxygen deficiency is detected.

If at medium altitudes the human body is affected by the whole complex of climatic and geographical factors, then at high mountains, the lack of oxygen in the tissues of the body, the so-called hypoxia, is of decisive importance.

Highlands, in turn, can also be conditionally divided (Fig. 1) into the following zones (according to E. Gippenreiter):

a) Full acclimatization zone - up to 5200-5300 m. In this zone, due to the mobilization of all adaptive reactions, the body successfully copes with oxygen deficiency and the manifestation of other negative factors of altitude. Therefore, here it is still possible to have long-term posts, stations, etc., that is, to live and work permanently.

b) Zone of incomplete acclimatization - up to 6000 m. Here, despite the commissioning of all compensatory-adaptive reactions, the human body can no longer fully counteract the influence of height. With a long (for several months) stay in this zone, fatigue develops, a person weakens, loses weight, atrophy of muscle tissues is observed, activity decreases sharply, the so-called high-altitude deterioration develops - a progressive deterioration in the general condition of a person with prolonged stay at high altitudes.

c) Adaptation zone - up to 7000 m. The adaptation of the body to altitude here is of a short, temporary nature. Even with a relatively short stay (on the order of two or three weeks) at such altitudes, adaptation reactions become depleted. In this regard, the body shows clear signs of hypoxia.

d) Zone of partial adaptation - up to 8000 m. When staying in this zone for 6-7 days, the body cannot provide the necessary amount of oxygen even to the most important organs and systems. Therefore, their activities are partially disrupted. Thus, the reduced efficiency of systems and organs responsible for replenishing energy costs does not ensure the restoration of strength, and human activity is largely due to reserves. At such altitudes, severe dehydration of the body occurs, which also worsens its general condition.

e) Limit (lethal) zone - over 8000 m. Gradually losing resistance to the action of heights, a person can stay at these heights due to internal reserves only for an extremely limited time, about 2 - 3 days.

The above values ​​of the altitudinal boundaries of the zones are, of course, average values. Individual tolerance, as well as a number of factors outlined below, can change the indicated values ​​\u200b\u200bfor each climber by 500 - 1000 m.

Adaptation of the body to altitude depends on age, sex, physical and mental state, degree of fitness, degree and duration of oxygen starvation, intensity of muscle effort, and experience at altitude. An important role is played by the individual resistance of the organism to oxygen starvation. Previous diseases, malnutrition, insufficient rest, lack of acclimatization significantly reduce the body's resistance to mountain sickness - a special condition of the body that occurs when inhaling rarefied air. Of great importance is the speed of climb. These conditions explain the fact that some people feel some signs of mountain sickness already at relatively low altitudes - 2100 - 2400 m, others are resistant to them up to 4200 - 4500 m, but when climbing to a height of 5800 - 6000 m signs of altitude sickness, expressed in varying degrees, appear in almost all people.

The development of mountain sickness is also affected by some climatic and geographical factors: increased solar radiation, low air humidity, prolonged low temperatures and their sharp difference between night and day, strong winds, and the degree of electrization of the atmosphere. Since these factors depend, in turn, on the latitude of the area, remoteness from water spaces, and similar reasons, the same height in different mountainous regions of the country has a different effect on the same person. For example, in the Caucasus, signs of mountain sickness can appear already at altitudes of 3000-3500 m, in Altai, Fann mountains and Pamir-Alai - 3700 - 4000 m, Tien Shan - 3800-4200 m and Pamir - 4500-5000 m.

Signs and effects of altitude sickness

Altitude sickness can manifest itself suddenly, especially in cases where a person in a short period of time has significantly exceeded the boundaries of his individual tolerance, experienced excessive overstrain in conditions of oxygen starvation. However, most mountain sickness develops gradually. Its first signs are general fatigue, which does not depend on the amount of work performed, apathy, muscle weakness, drowsiness, malaise, dizziness. If a person continues to remain at a height, then the symptoms of the disease increase: digestion is disturbed, frequent nausea and even vomiting are possible, respiratory rhythm disorder, chills and fever appear. The recovery process is rather slow.

In the early stages of the development of the disease, no special treatment measures are required. Most often, after active work and proper rest, the symptoms of the disease disappear - this indicates the onset of acclimatization. Sometimes the disease continues to progress, passing into the second stage - chronic. Its symptoms are the same, but expressed to a much stronger degree: the headache can be extremely acute, drowsiness is more pronounced, the vessels of the hands are full of blood, nosebleeds are possible, shortness of breath is pronounced, the chest becomes wide, barrel-shaped, there is increased irritability, it is possible loss of consciousness. These signs indicate a serious illness and the need for urgent transportation of the patient down. Sometimes the listed manifestations of the disease are preceded by a stage of excitation (euphoria), which is very reminiscent of alcohol intoxication.

The mechanism of the development of mountain sickness is associated with insufficient blood oxygen saturation, which affects the functions of many internal organs and systems. Of all the tissues of the body, the nervous one is the most sensitive to oxygen deficiency. In a person who got to a height of 4000 - 4500 m and prone to mountain sickness, as a result of hypoxia, arousal first arises, expressed in the appearance of a feeling of complacency and own strength. He becomes cheerful, talkative, but at the same time loses control over his actions, cannot really assess the situation. After a while, a period of depression sets in. Gaiety is replaced by sullenness, grumpiness, even pugnacity, and even more dangerous bouts of irritability. Many of these people do not rest in a dream: the dream is restless, accompanied by fantastic dreams that are in the nature of bad forebodings.

At high altitudes, hypoxia has a more serious effect on the functional state of higher nerve centers, causing dulling of sensitivity, impaired judgment, loss of self-criticism, interest and initiative, and sometimes memory loss. The speed and accuracy of the reaction noticeably decreases, as a result of the weakening of the processes of internal inhibition, the coordination of movement is upset. Mental and physical depression appears, expressed in slowness of thinking and actions, a noticeable loss of intuition and the ability to think logically, and a change in conditioned reflexes. However, at the same time, a person believes that his consciousness is not only clear, but also unusually sharp. He continues to do what he was doing before the severe effects of hypoxia on him, despite the sometimes dangerous consequences of his actions.

The sick person may develop an obsession, a sense of the absolute correctness of his actions, intolerance of critical remarks, and this, if the head of the group, a person responsible for the lives of other people, is in such a state, becomes especially dangerous. It has been observed that under the influence of hypoxia, people often do not make any attempts to get out of a clearly dangerous situation.

It is important to know what are the most common changes in human behavior that occur at altitude under the influence of hypoxia. In terms of frequency of occurrence, these changes are arranged in the following sequence:

Disproportionately large efforts in the performance of the task;

More critical attitude towards other participants of the trip;

Unwillingness to do mental work;

Increased irritability of the senses;

Touchiness;

Irritability with comments on work;

Difficulty concentrating;

Slow thinking;

Frequent, obsessive return to the same topic;

Difficulty in remembering.

As a result of hypoxia, thermoregulation can also be disturbed, due to which, in some cases, at low temperatures, the production of heat by the body decreases, and at the same time, its loss through the skin increases. Under these conditions, a person with mountain sickness is more susceptible to cooling than other participants in the trip. In other cases, chills and an increase in body temperature by 1-1.5 ° C are possible.

Hypoxia also affects many other organs and systems of the body.

Respiratory system.

If at rest a person at a height does not experience shortness of breath, lack of air or difficulty breathing, then during physical exertion at high altitude, all these phenomena begin to be noticeably felt. For example, one of the participants in climbing Everest took 7-10 full breaths and exhalations for each step at an altitude of 8200 meters. But even with such a slow pace of movement, he rested for up to two minutes every 20-25 meters of the path. Another participant of the ascent in one hour of movement, while being at an altitude of 8500 meters, climbed along a fairly easy section to a height of only about 30 meters.

Working capacity.

It is well known that any muscle activity, and especially intense, is accompanied by an increase in blood supply to the working muscles. However, if the body can provide the necessary amount of oxygen relatively easily under the conditions of the plain, then with the ascent to a great height, even with the maximum use of all adaptive reactions, the supply of oxygen to the muscles is disproportionate to the degree of muscle activity. As a result of this discrepancy, oxygen starvation develops, and under-oxidized metabolic products accumulate in the body in excess quantities. Therefore, human performance decreases sharply with increasing height. So (according to E. Gippenreiter) at an altitude of 3000 m it is 90%, at an altitude of 4000 m. -80%, 5500 m- 50%, 6200 m- 33% and 8000 m- 15-16% of the maximum level of work done at sea level.

Even at the end of work, despite the cessation of muscle activity, the body continues to be in tension, consuming an increased amount of oxygen for some time in order to eliminate oxygen debt. It should be noted that the time during which this debt is liquidated depends not only on the intensity and duration of muscle work, but also on the degree of training of a person.

The second, although less important reason for the decrease in the body's performance is the overload of the respiratory system. It is the respiratory system, by strengthening its activity up to a certain time, that can compensate for the sharply increasing oxygen demand of the body in a rarefied air environment.

Table 1

Height in meters	Increase in pulmonary ventilation in % (with the same work)

However, the possibilities of pulmonary ventilation have their own limit, which the body reaches before the maximum working capacity of the heart occurs, which reduces the required amount of oxygen consumed to a minimum. Such restrictions are explained by the fact that a decrease in the partial pressure of oxygen leads to an increase in pulmonary ventilation, and, consequently, to an increased "washout" of CO 2 from the body. But a decrease in the partial pressure of CO 2 reduces the activity of the respiratory center and thereby limits the volume of pulmonary ventilation.

At altitude, pulmonary ventilation reaches the limit values ​​already when the load is average for normal conditions. Therefore, the maximum amount of intensive work for a certain time that a tourist can perform in high mountains is less, and the recovery period after working in the mountains is longer than at sea level. However, with a long stay at the same altitude (up to 5000-5300 m) due to the acclimatization of the body, the level of working capacity increases.

The digestive system.

At altitude, appetite changes significantly, the absorption of water and nutrients decreases, the secretion of gastric juice decreases, the functions of the digestive glands change, which leads to disruption of the processes of digestion and absorption of food, especially fats. As a result, a person loses weight dramatically. So, during one of the expeditions to Everest, climbers who lived at an altitude of more than 6000 m within 6-7 weeks, lost in weight from 13.6 to 22.7 kg. At a height, a person can feel an imaginary feeling of fullness in the stomach, bursting in the epigastric region, nausea, diarrhea that is not amenable to drug treatment.

Vision.

At altitudes of about 4500 m normal visual acuity is possible only at a brightness 2.5 times greater than normal for flat conditions. At these heights, there is a narrowing of the peripheral field of vision and a noticeable "fogging" of vision in general. At high altitudes, the accuracy of fixing the gaze and the correctness of determining the distance also decrease. Even in mid-mountain conditions, vision weakens at night, and the period of adaptation to darkness lengthens.

pain sensitivity

as hypoxia increases, it decreases up to its complete loss.

Dehydration of the body.

The excretion of water from the body, as is known, is carried out mainly by the kidneys (1.5 liters of water per day), skin (1 liter), lungs (about 0.4 l) and intestines (0.2-0.3 l). It has been established that the total water consumption in the body, even in a state of complete rest, is 50-60 G in hour. With average physical activity in normal climatic conditions at sea level, water consumption increases to 40-50 grams per day for every kilogram of human weight. In total, on average, under normal conditions, about 3 l water. With increased muscular activity, especially in hot conditions, the release of water through the skin sharply increases (sometimes up to 4-5 liters). But intense muscular work performed in high altitude conditions, due to lack of oxygen and dry air, sharply increases pulmonary ventilation and thereby increases the amount of water released through the lungs. All this leads to the fact that the total loss of water for participants in difficult high-mountain trips can reach 7-10 l per day.

Statistics show that in high altitude conditions more than doubles morbidity of the respiratory system. Inflammation of the lungs often takes on a croupous form, proceeds much more severely, and the resorption of inflammatory foci is much slower than in plain conditions.

Inflammation of the lungs begins after physical overwork and hypothermia. In the initial stage, there is a feeling of poor health, some shortness of breath, rapid pulse, cough. But after about 10 hours, the patient's condition deteriorates sharply: the respiratory rate is over 50, the pulse is 120 per minute. Despite taking sulfonamides, pulmonary edema develops already after 18-20 hours, which is a great danger in high altitude conditions. The first signs of acute pulmonary edema: dry cough, complaints of pressure slightly below the sternum, shortness of breath, weakness during exercise. In serious cases, there is hemoptysis, suffocation, severe confusion, followed by death. The course of the disease often does not exceed one day.

The basis for the formation of pulmonary edema at altitude is, as a rule, the phenomenon of increasing the permeability of the walls of the pulmonary capillaries and alveoli, as a result of which foreign substances (protein masses, blood elements and microbes) penetrate into the alveoli of the lungs. Therefore, the useful capacity of the lungs is sharply reduced in a short time. Hemoglobin of arterial blood, washing the outer surface of the alveoli, filled not with air, but with protein masses and blood elements, cannot be adequately saturated with oxygen. As a result, from insufficient (below the permissible norm) supply of oxygen to body tissues, a person quickly dies.

Therefore, even in case of the slightest suspicion of a respiratory disease, the group must immediately take measures to bring the sick person down as soon as possible, preferably to an altitude of about 2000-2500 meters.

The mechanism of development of mountain sickness

Dry atmospheric air contains: 78.08% nitrogen, 20.94% oxygen, 0.03% carbon dioxide, 0.94% argon and 0.01% other gases. When rising to a height, this percentage does not change, but the density of the air changes, and, consequently, the magnitude of the partial pressures of these gases.

According to the law of diffusion, gases pass from an environment with a higher partial pressure to an environment with a lower pressure. Gas exchange, both in the lungs and in human blood, is carried out due to the existing difference in these pressures.

At normal atmospheric pressure 760 mmp t. st. partial pressure of oxygen is:

760x0.2094=159 mmHg Art., where 0.2094 is the percentage of oxygen in the atmosphere, equal to 20.94%.

Under these conditions, the partial pressure of oxygen in the alveolar air (inhaled with air and entering the alveoli of the lungs) is about 100 mmHg Art. Oxygen is poorly soluble in blood, but it binds to the hemoglobin protein found in red blood cells - erythrocytes. Under normal conditions, due to the high partial pressure of oxygen in the lungs, hemoglobin in arterial blood is saturated with oxygen up to 95%.

When passing through the capillaries of tissues, hemoglobin in the blood loses about 25% of oxygen. Therefore, venous blood carries up to 70% oxygen, the partial pressure of which, as can be easily seen from the graph (Fig. 2), is

0 10 20 30 40 50 60 70 80 90 100

Partial pressure of oxygen mm .pm .cm.

Rice. 2.

at the time of the flow of venous blood to the lungs at the end of the circulatory cycle, only 40 mmHg Art. Thus, there is a significant pressure difference between venous and arterial blood, equal to 100-40=60 mmHg Art.

Between carbon dioxide inhaled with air (partial pressure 40 mmHg Art.), and carbon dioxide flowing with venous blood to the lungs at the end of the circulatory cycle (partial pressure 47-50 mmHg.), differential pressure is 7-10 mmHg Art.

As a result of the existing pressure drop, oxygen passes from the pulmonary alveoli into the blood, and directly in the tissues of the body, this oxygen diffuses from the blood into the cells (into an environment with an even lower partial pressure). Carbon dioxide, on the contrary, first passes from the tissues into the blood, and then, when venous blood approaches the lungs, from the blood into the alveoli of the lung, from where it is exhaled into the surrounding air. (Fig. 3).

Rice. 3.

With ascent to altitude, the partial pressures of gases decrease. So, at an altitude of 5550 m(corresponding to an atmospheric pressure of 380 mmHg Art.) for oxygen it is:

380x0.2094=80 mmHg Art.,

that is, it is reduced by half. At the same time, of course, the partial pressure of oxygen in arterial blood also decreases, as a result of which not only the saturation of blood hemoglobin with oxygen decreases, but also due to a sharp reduction in the pressure difference between arterial and venous blood, the transfer of oxygen from blood to tissues worsens significantly. This is how oxygen deficiency-hypoxia occurs, which can lead to a person's illness with mountain sickness.

Naturally, a number of protective compensatory-adaptive reactions arise in the human body. So, first of all, the lack of oxygen leads to the excitation of chemoreceptors - nerve cells that are very sensitive to a decrease in the partial pressure of oxygen. Their excitation serves as a signal for deepening and then quickening of breathing. The resulting expansion of the lungs increases their alveolar surface and thereby contributes to a more rapid saturation of hemoglobin with oxygen. Thanks to this, as well as a number of other reactions, a large amount of oxygen enters the body.

However, with increased respiration, ventilation of the lungs increases, during which there is an increased excretion (“washing out”) of carbon dioxide from the body. This phenomenon is especially enhanced with the intensification of work in high altitude conditions. So, if on the plain at rest within one minute approximately 0.2 l CO 2, and during hard work - 1.5-1.7 l, then in high altitude conditions, on average, the body loses about 0.3-0.35 per minute l CO 2 at rest and up to 2.5 l during intense muscular work. As a result, there is a lack of CO 2 in the body - the so-called hypocapnia, characterized by a decrease in the partial pressure of carbon dioxide in arterial blood. But carbon dioxide plays an important role in regulating the processes of respiration, circulation and oxidation. A serious lack of CO 2 can lead to paralysis of the respiratory center, to a sharp drop in blood pressure, deterioration of the heart, and disruption of nervous activity. Thus, a decrease in CO 2 blood pressure by 45 to 26 mm. r t. reduces blood circulation to the brain by almost half. That is why cylinders intended for breathing at high altitudes are filled not with pure oxygen, but with its mixture with 3-4% carbon dioxide.

A decrease in the content of CO 2 in the body disrupts the acid-base balance towards an excess of alkalis. Trying to restore this balance, the kidneys intensively remove this excess of alkalis from the body along with urine for several days. Thus, acid-base balance is achieved at a new, lower level, which is one of the main signs of the completion of the adaptation period (partial acclimatization). But at the same time, the value of the alkaline reserve of the body is violated (decreases). In case of mountain sickness, a decrease in this reserve contributes to its further development. This is explained by the fact that a rather sharp decrease in the amount of alkalis reduces the ability of the blood to bind acids (including lactic acid) that are formed during hard work. This in a short time changes the acid-base ratio in the direction of an excess of acids, which disrupts the work of a number of enzymes, leads to disorganization of the metabolic process and, most importantly, inhibition of the respiratory center occurs in a seriously ill patient. As a result, breathing becomes shallow, carbon dioxide is not completely removed from the lungs, accumulates in them and prevents oxygen from reaching hemoglobin. At the same time, suffocation quickly sets in.

From all that has been said, it follows that although the main cause of mountain sickness is a lack of oxygen in the tissues of the body (hypoxia), the lack of carbon dioxide (hypocapnia) also plays a rather large role here.

Acclimatization

With a long stay at a height in the body, a number of changes occur, the essence of which is to preserve the normal functioning of a person. This process is called acclimatization. Acclimatization is the sum of adaptive-compensatory reactions of the body, as a result of which a good general condition is maintained, weight constancy, normal working capacity and the normal course of psychological processes are maintained. Distinguish between complete and incomplete, or partial, acclimatization.

Due to the relatively short period of stay in the mountains, mountain tourists and climbers are characterized by partial acclimatization and adaptation-short-term(as opposed to the final or long-term) adaptation of the body to new climatic conditions.

In the process of adaptation to a lack of oxygen in the body, the following changes occur:

Since the cerebral cortex is extremely sensitive to oxygen deficiency, the body in high altitude conditions primarily seeks to maintain proper oxygen supply to the central nervous system by reducing the oxygen supply to other, less important organs;

The respiratory system is also largely sensitive to a lack of oxygen. The respiratory organs react to the lack of oxygen first by deeper breathing (increasing its volume):

table 2

Height, m		5000	6000
Inhaled volume air, ml			1000

and then an increase in the frequency of breathing:

Table 3
	Breathing rate
The nature of the movement	at sea level	at an altitude of 4300 m
Walking at speed 6,4 km/h	17,2
Walking at a speed of 8.0 km/h	20,0

As a result of some reactions caused by oxygen deficiency, not only the number of erythrocytes (red blood cells containing hemoglobin) increases in the blood, but also the amount of hemoglobin itself (Fig. 4).

All this causes an increase in the oxygen capacity of the blood, that is, the ability of the blood to carry oxygen to the tissues and thus supply the tissues with the necessary amount of it increases. It should be noted that the increase in the number of erythrocytes and the percentage of hemoglobin is more pronounced if the ascent is accompanied by an intense muscle load, that is, if the adaptation process is active. The degree and rate of growth in the number of erythrocytes and hemoglobin content also depend on the geographical features of certain mountainous regions.

Increases in the mountains and the total amount of circulating blood. However, the load on the heart does not increase, since at the same time there is an expansion of capillaries, their number and length increase.

In the first days of a person's stay in high mountains (especially in poorly trained people), the minute volume of the heart increases, and the pulse increases. So, for physically poorly trained climbers at a height 4500m pulse increases by an average of 15, and at an altitude of 5500 m - at 20 beats per minute.

At the end of the acclimatization process at altitudes up to 5500 m all of these parameters are reduced to normal values, typical for normal activities at low altitudes. The normal functioning of the gastrointestinal tract is also restored. However, at high altitudes (more than 6000 m) pulse, respiration, the work of the cardiovascular system never decrease to a normal value, because here some organs and systems of a person are constantly under conditions of a certain tension. So, even during sleep at altitudes of 6500-6800 m the pulse rate is about 100 beats per minute.

It is quite obvious that for each person the period of incomplete (partial) acclimatization has a different duration. It occurs much faster and with less functional deviations in physically healthy people aged 24 to 40 years. But in any case, a 14-day stay in the mountains under conditions of active acclimatization is sufficient for a normal organism to adapt to new climatic conditions.

To eliminate the likelihood of a serious illness with mountain sickness, as well as to reduce the time of acclimatization, the following set of measures can be recommended, carried out both before leaving for the mountains and during the trip.

Before a long alpine journey, including passes above 5000 m in the route of its route m, all candidates must be subjected to a special medical-physiological examination. Persons who do not tolerate oxygen deficiency, are physically insufficiently prepared, and who have suffered pneumonia, tonsillitis or serious influenza during the pre-trek training period, should not be allowed to participate in such trips.

The period of partial acclimatization can be shortened if the participants of the upcoming trip, a few months before going to the mountains, start regular general physical training, especially to increase the endurance of the body: long-distance running, swimming, underwater sports, skating and skiing. During such training, a temporary lack of oxygen occurs in the body, which is the higher, the greater the intensity and duration of the load. Since the body works here in conditions that are somewhat similar in terms of oxygen deficiency to staying at a height, a person develops an increased resistance of the body to a lack of oxygen when performing muscular work. In the future, in mountainous conditions, this will facilitate adaptation to height, speed up the process of adaptation, and make it less painful.

You should know that for tourists who are physically unprepared for a high-altitude trip, the vital capacity of the lungs at the beginning of the trip even decreases slightly, the maximum performance of the heart (compared to trained participants) also becomes 8-10% less, and the reaction of increasing hemoglobin and erythrocytes with oxygen deficiency is delayed .

The following activities are carried out directly during the trip: active acclimatization, psychotherapy, psychoprophylaxis, organization of appropriate nutrition, the use of vitamins and adaptogens (drugs that increase the body's performance), complete cessation of smoking and alcohol, systematic condition control health, the use of certain drugs.

Active acclimatization for climbing ascents and for high-mountain hiking trips has a difference in the methods of its implementation. This difference is explained, first of all, by a significant difference in the heights of the climbing objects. So, if for climbers this height can be 8842 m, then for the most prepared tourist groups it will not exceed 6000-6500 m(several passes in the region of the High Wall, Zaalai and some other ridges in the Pamirs). The difference lies in the fact that climbing to the peaks along technically difficult routes takes place over several days, and along difficult traverses - even weeks (without significant loss of height at certain intermediate stages), while in high-mountain hiking trips that have, as a rule, a greater length, it takes less time to overcome the passes.

Lower heights, shorter stay on these W- honeycombs and a faster descent with a significant loss of altitude to a greater extent facilitate the process of acclimatization for tourists, and quite multiple the alternation of ascents and descents softens, and even stops the development of mountain sickness.

Therefore, climbers during high-altitude ascents are forced at the beginning of the expedition to allocate up to two weeks for training (acclimatization) ascents to lower peaks, which differ from the main object of climbing to a height of about 1000 meters. For tourist groups, whose routes pass through passes with a height of 3000-5000 m, special acclimatization exits are not required. For this purpose, as a rule, it is enough to choose such a route route, in which during the first week - 10 days the height of the passes passed by the group would increase gradually.

Since the greatest malaise caused by the general fatigue of a tourist who has not yet become involved in the hiking life is usually felt in the first days of the hike, even when organizing a day trip at this time, it is recommended to conduct classes on movement technique, on the construction of snow huts or caves, as well as exploration or training exits. to height. These practical exercises and exits should be carried out at a good pace, which makes the body react faster to rarefied air, more actively adapt to changes in climatic conditions. N. Tenzing's recommendations are interesting in this regard: at a height, even at a bivouac, you need to be physically active - warm snow water, monitor the condition of the tents, check equipment, move more, for example, after setting up the tents, take part in the construction of a snow kitchen, help distribute prepared food by tents.

Proper nutrition is also essential in the prevention of mountain sickness. At an altitude of over 5000 m the daily diet should have at least 5000 large calories. The content of carbohydrates in the diet should be increased by 5-10% compared to the usual diet. In areas associated with intense muscle activity, first of all, an easily digestible carbohydrate - glucose should be consumed. Increased carbohydrate intake contributes to the formation of more carbon dioxide, which the body lacks. The amount of fluid consumed in high altitude conditions and, especially, when performing intensive work associated with movement along difficult sections of the route, should be at least 4-5 l per day. This is the most decisive measure in the fight against dehydration. In addition, an increase in the volume of fluid consumed contributes to the removal of underoxidized metabolic products from the body through the kidneys.

The body of a person who prolonged intensive work in high altitude conditions requires an increased (2-3 times) amount of vitamins, especially those that are part of the enzymes involved in the regulation of redox processes and are closely related to metabolism. These are B vitamins, where B 12 and B 15 are the most important, as well as B 1, B 2 and B 6. So, vitamin B 15, in addition to the above, helps to increase the body's performance at altitude, greatly facilitating the performance of large and intense loads, increases the efficiency of oxygen use, activates oxygen metabolism in tissue cells, and increases altitude stability. This vitamin enhances the mechanism of active adaptation to a lack of oxygen, as well as fat oxidation at altitude.

In addition to them, vitamins C, PP and folic acid in combination with iron glycerophosphate and metacil also play an important role. Such a complex has an effect on an increase in the number of red blood cells and hemoglobin, that is, an increase in the oxygen capacity of the blood.

The acceleration of adaptation processes is also influenced by the so-called adaptogens - ginseng, eleutherococcus and acclimatizin (a mixture of eleutherococcus, lemongrass and yellow sugar). E. Gippenreiter recommends the following complex of drugs that increase the body's adaptability to hypoxia and facilitate the course of mountain sickness: eleutherococcus, diabazole, vitamins A, B 1, B 2, B 6, B 12, C, PP, calcium pantothenate, methionine, calcium gluconate, calcium glycerophosphate and potassium chloride. The mixture proposed by N. Sirotinin is also effective: 0.05 g of ascorbic acid, 0.5 G. citric acid and 50 g of glucose per dose. We can also recommend a dry blackcurrant drink (in briquettes of 20 G), containing citric and glutamic acids, glucose, sodium chloride and phosphate.

How long, upon returning to the plain, does the organism retain the changes that have occurred in it during the process of acclimatization?

At the end of the journey in the mountains, depending on the altitude of the route, the changes acquired in the process of acclimatization in the respiratory system, blood circulation and the composition of the blood itself pass quickly enough. So, the increased content of hemoglobin decreases to normal in 2-2.5 months. Over the same period, the increased ability of the blood to carry oxygen also decreases. That is, the acclimatization of the body to the height lasts only up to three months.

True, after repeated trips to the mountains, a kind of “memory” is developed in the body for adaptive reactions to altitude. Therefore, at the next trip to the mountains, its organs and systems, already along the “beaten paths”, quickly find the right way to adapt the body to a lack of oxygen.

Help for mountain sickness

If, despite the measures taken, any of the participants in the high-mountain hike shows symptoms of altitude sickness, it is necessary:

For headaches, take Citramon, Pyramidone (no more than 1.5 g per day), Analgin (no more than 1 G for a single dose and 3 g per day) or their combinations (troychatka, quintuple);

With nausea and vomiting - Aeron, sour fruits or their juices;

For insomnia - noxiron, when a person falls asleep badly, or Nembutal, when sleep is not deep enough.

When using drugs in high altitude conditions, special care should be taken. First of all, this applies to biologically active substances (phenamine, phenatin, pervitin), which stimulate the activity of nerve cells. It should be remembered that these substances create only a short-term effect. Therefore, it is better to use them only when absolutely necessary, and even then already during the descent, when the duration of the upcoming movement is not long. An overdose of these drugs leads to exhaustion of the nervous system, to a sharp decrease in efficiency. An overdose of these drugs is especially dangerous in conditions of prolonged oxygen deficiency.

If the group decided to urgently descend the sick participant, then during the descent it is necessary not only to systematically monitor the patient's condition, but also regularly inject antibiotics and drugs that stimulate the human heart and respiratory activity (lobelia, cardiamine, corazol or norepinephrine).

SUN EXPOSURE

Sun burns.

From prolonged exposure to the sun on the human body, sunburns form on the skin, which can cause a painful condition for a tourist.

Solar radiation is a stream of rays of the visible and invisible spectrum, which have different biological activity. When exposed to the sun, there is a simultaneous effect of:

Direct solar radiation;

Scattered (arrived due to the scattering of part of the flow of direct solar radiation in the atmosphere or reflection from clouds);

Reflected (as a result of the reflection of rays from surrounding objects).

The magnitude of the flow of solar energy falling on one or another specific area of ​​​​the earth's surface depends on the height of the sun, which, in turn, is determined by the geographical latitude of this area, the time of year and day.

If the sun is at its zenith, then its rays travel the shortest path through the atmosphere. At a standing height of the sun of 30 °, this path doubles, and at sunset - 35.4 times more than with a sheer fall of the rays. Passing through the atmosphere, especially through its lower layers containing particles of dust, smoke and water vapor in suspension, the sun's rays are absorbed and scattered to a certain extent. Therefore, the greater the path of these rays through the atmosphere, the more polluted it is, the lower the intensity of solar radiation they have.

With the rise to a height, the thickness of the atmosphere through which the sun's rays pass decreases, and the most dense, moistened and dusty lower layers are excluded. Due to the increase in the transparency of the atmosphere, the intensity of direct solar radiation increases. The nature of the change in intensity is shown in the graph (Fig. 5).

Here, the flux intensity at sea level is taken as 100%. The graph shows that the amount of direct solar radiation in the mountains increases significantly: by 1-2% with an increase for every 100 meters.

The total intensity of the direct solar radiation flux, even at the same height of the sun, changes its value depending on the season. Thus, in summer, due to an increase in temperature, increasing humidity and dust reduce the transparency of the atmosphere to such an extent that the magnitude of the flux at a sun height of 30 ° is 20% less than in winter.

However, not all components of the spectrum of sunlight change their intensity to the same extent. The intensity increases especially ultraviolet rays are the most active physiologically: it has a pronounced maximum at a high position of the sun (at noon). The intensity of these rays during this period in the same weather conditions is the time required for

redness of the skin, at a height of 2200 m 2.5 times, and at an altitude of 5000 m 6 times less than at an altitude of 500 winds (Fig. 6). With a decrease in the height of the sun, this intensity drops sharply. So, for a height of 1200 m this dependence is expressed by the following table (the intensity of ultraviolet rays at a sun height of 65 ° is taken as 100%):

Table4

Height of the sun, deg.
Intensity of ultraviolet rays, %		76,2	35,3	13,0

If the clouds of the upper tier weaken the intensity of direct solar radiation, usually only to an insignificant extent, then the denser clouds of the middle and especially the lower tiers can reduce to zero. .

Diffused radiation plays a significant role in the total amount of incoming solar radiation. Scattered radiation illuminates places that are in the shade, and when the sun closes over some area with dense clouds, it creates a general daylight illumination.

The nature, intensity and spectral composition of scattered radiation are related to the height of the sun, the transparency of the air and the reflectivity of clouds.

Scattered radiation in a clear sky without clouds, caused mainly by atmospheric gas molecules, differs sharply in its spectral composition both from other types of radiation and from scattered radiation under a cloudy sky. The maximum energy in its spectrum is shifted to shorter wavelengths. And although the intensity of scattered radiation in a cloudless sky is only 8-12% of the intensity of direct solar radiation, the abundance of ultraviolet rays in the spectral composition (up to 40-50% of the total number of scattered rays) indicates its significant physiological activity. The abundance of short-wavelength rays also explains the bright blue color of the sky, the blueness of which is the more intense, the cleaner the air.

In the lower layers of the air, when the sun's rays are scattered from large suspended particles of dust, smoke and water vapor, the intensity maximum shifts to the region of longer waves, as a result of which the color of the sky becomes whitish. With a whitish sky or in the presence of a weak fog, the total intensity of scattered radiation increases by 1.5-2 times.

When clouds appear, the intensity of scattered radiation increases even more. Its value is closely related to the amount, shape and location of clouds. So, if at a high standing of the sun the sky is covered by clouds by 50-60%, then the intensity of scattered solar radiation reaches values ​​equal to the flux of direct solar radiation. With a further increase in cloudiness and especially with its compaction, the intensity decreases. With cumulonimbus clouds, it can even be lower than with a cloudless sky.

It should be borne in mind that if the flux of scattered radiation is higher, the lower the transparency of the air, then the intensity of ultraviolet rays in this type of radiation is directly proportional to the transparency of the air. In the daily course of changes in illumination, the greatest value of scattered ultraviolet radiation falls on the middle of the day, and in the annual course - in winter.

The value of the total flux of scattered radiation is also influenced by the energy of the rays reflected from the earth's surface. So, in the presence of pure snow cover, scattered radiation increases by 1.5-2 times.

The intensity of reflected solar radiation depends on the physical properties of the surface and on the angle of incidence of the sun's rays. Wet black soil reflects only 5% of the rays falling on it. This is because the reflectivity decreases significantly with increasing soil moisture and roughness. But alpine meadows reflect 26%, polluted glaciers - 30%, clean glaciers and snowy surfaces - 60-70%, and freshly fallen snow - 80-90% of the incident rays. Thus, when moving in the highlands along snow-covered glaciers, a person is affected by a reflected stream, which is almost equal to direct solar radiation.

The reflectivity of individual rays included in the spectrum of sunlight is not the same and depends on the properties of the earth's surface. So, water practically does not reflect ultraviolet rays. The reflection of the latter from the grass is only 2-4%. At the same time, for freshly fallen snow, the reflection maximum is shifted to the short-wavelength range (ultraviolet rays). You should know that the number of ultraviolet rays reflected from the earth's surface, the greater, the brighter this surface. It is interesting to note that the reflectivity of human skin for ultraviolet rays is on average 1-3%, that is, 97-99% of these rays falling on the skin are absorbed by it.

Under normal conditions, a person is faced not with one of the listed types of radiation (direct, diffuse or reflected), but with their total effect. On the plain, this total exposure under certain conditions can be more than twice the intensity of exposure to direct sunlight. When traveling in the mountains at medium altitudes, the irradiation intensity as a whole can be 3.5-4 times, and at an altitude of 5000-6000 m 5-5.5 times higher than normal flat conditions.

As has already been shown, with increasing altitude, the total flux of ultraviolet rays especially increases. At high altitudes, their intensity can reach values ​​exceeding the intensity of ultraviolet irradiation with direct solar radiation in plain conditions by 8-10 times!

Influencing open areas of the human body, ultraviolet rays penetrate the human skin to a depth of only 0.05 to 0.5 mm, causing, at moderate doses of radiation, redness, and then darkening (sunburn) of the skin. In the mountains, open areas of the body are exposed to solar radiation throughout the daylight hours. Therefore, if the necessary measures are not taken in advance to protect these areas, a body burn can easily occur.

Outwardly, the first signs of burns associated with solar radiation do not correspond to the degree of damage. This degree comes to light a little later. According to the nature of the lesion, burns are generally divided into four degrees. For the considered sunburns, in which only the upper layers of the skin are affected, only the first two (the mildest) degrees are inherent.

I - the mildest degree of burn, characterized by reddening of the skin in the burn area, swelling, burning, pain and some development of skin inflammation. Inflammatory phenomena pass quickly (after 3-5 days). Pigmentation remains in the burn area, sometimes peeling of the skin is observed.

II degree is characterized by a more pronounced inflammatory reaction: intense reddening of the skin and exfoliation of the epidermis with the formation of blisters filled with a clear or slightly cloudy liquid. Full recovery of all layers of the skin occurs in 8-12 days.

Burns of the 1st degree are treated by skin tanning: the burnt areas are moistened with alcohol, a solution of potassium permanganate. In the treatment of second degree burns, the primary treatment of the burn site is performed: rubbing with gasoline or 0.5%. ammonia solution, irrigation of the burnt area with antibiotic solutions. Considering the possibility of introducing an infection in field conditions, it is better to close the burn area with an aseptic bandage. A rare change of dressing contributes to the speedy recovery of the affected cells, since the layer of delicate young skin is not injured.

During a mountain or ski trip, the neck, earlobes, face and skin of the outer side of the hands suffer most from exposure to direct sunlight. As a result of exposure to scattered, and when moving through the snow and reflected rays, the chin, lower part of the nose, lips, skin under the knees are burned. Thus, almost any open area of ​​the human body is prone to burns. On warm spring days, when driving in the highlands, especially in the first period, when the body is not yet tanned, in no case should one allow a long (over 30 minutes) exposure to the sun without a shirt. The delicate skin of the abdomen, lower back and lateral surfaces of the chest are most sensitive to ultraviolet rays. It is necessary to strive to ensure that in sunny weather, especially in the middle of the day, all parts of the body are protected from exposure to all types of sunlight. In the future, with repeated repeated exposure to ultraviolet radiation, the skin acquires a tan and becomes less sensitive to these rays.

The skin of the hands and face is the least susceptible to UV rays.

Rice. 7

But due to the fact that it is the face and hands that are the most exposed parts of the body, they suffer most from sunburn. Therefore, on sunny days, the face should be protected with a gauze bandage. In order to prevent the gauze from getting into the mouth during deep breathing, it is advisable to use a piece of wire (length 20-25 cm, diameter 3 mm), passed through the bottom of the bandage and curved in an arc (rice. 7).

In the absence of a mask, the parts of the face that are most susceptible to burns can be covered with a protective cream such as "Ray" or "Nivea", and lips with colorless lipstick. To protect the neck, it is recommended to hem double-folded gauze to the headgear from the back of the head. Take special care of your shoulders and hands. If with a burn

shoulders, the injured participant cannot carry a backpack and all his load falls on other comrades with an additional weight, then if the burns of the hands are burned, the victim will not be able to provide reliable insurance. Therefore, on sunny days, wearing a long-sleeved shirt is a must. The back of the hands (when moving without gloves) must be covered with a layer of protective cream.

snow blindness

(eye burn) occurs with a relatively short (within 1-2 hours) movement in the snow on a sunny day without goggles as a result of a significant intensity of ultraviolet rays in the mountains. These rays affect the cornea and conjunctiva of the eyes, causing them to burn. Within a few hours, pain (“sand”) and lacrimation appear in the eyes. The victim cannot look at light, even at a lit match (photophobia). There is some swelling of the mucous membrane, in the future blindness may occur, which, if timely measures are taken, disappears without a trace after 4-7 days.

To protect the eyes from burns, it is necessary to use goggles, the dark lenses of which (orange, dark purple, dark green or brown) absorb ultraviolet rays to a large extent and reduce the overall illumination of the area, preventing eye fatigue. It is useful to know that the color orange improves the feeling of relief in conditions of snowfall or light fog, creates the illusion of sunlight. Green color brightens up the contrasts between brightly lit and shady areas of the area. Since bright sunlight reflected from a white snowy surface has a strong stimulating effect on the nervous system through the eyes, wearing goggles with green lenses has a calming effect.

The use of goggles made of organic glass in high-altitude and ski trips is not recommended, since the spectrum of the absorbed part of the ultraviolet rays of such glass is much narrower, and some of these rays, which have the shortest wavelength and have the greatest physiological effect, still reach the eyes. Prolonged exposure to such, even a reduced amount of ultraviolet rays, can eventually lead to eye burns.

It is also not recommended to take canned glasses that fit snugly to the face on a hike. Not only glasses, but also the skin of the part of the face covered by them fogs up a lot, causing an unpleasant sensation. Much better is the use of conventional glasses with sidewalls made of a wide adhesive plaster. (Fig. 8).

Rice. eight.

Participants in long hikes in the mountains must always have spare glasses at the rate of one pair for three people. In the absence of spare glasses, you can temporarily use a gauze blindfold or put cardboard tape over your eyes, making pre-narrow slits in it in order to see only a limited area of ​​\u200b\u200bthe area.

First aid for snow blindness: rest for the eyes (dark bandage), washing the eyes with a 2% solution of boric acid, cold lotions from tea broth.

Sunstroke

A severe painful condition that suddenly arises during long transitions as a result of many hours of exposure to infrared rays of direct sunlight on an uncovered head. At the same time, in the conditions of the campaign, the back of the head is exposed to the greatest influence of the rays. The outflow of arterial blood that occurs in this case and a sharp stagnation of venous blood in the veins of the brain lead to its edema and loss of consciousness.

The symptoms of this disease, as well as the actions of the first aid team, are the same as those for heat stroke.

A headgear that protects the head from exposure to sunlight and, in addition, retains the possibility of heat exchange with the surrounding air (ventilation) thanks to a mesh or a series of holes, is a mandatory accessory for a participant in a mountain trip.

Abstract for the work.

The idea of ​​creating a collection of tasks on an environmental theme came to me a long time ago. These tasks have been accumulating for a long time. Each teacher is faced with the problem of finding material, including tasks on a specific topic, corresponding to a future lesson or extracurricular activity. Few people have not delved into the mountain of literature in order to find the right fact or a problem suitable for the topic.

Environmental issues in the lessons of physics, voluntarily or involuntarily, have to be touched upon, because progress is impossible without the development of technology, just as the development of technology is impossible without physics. Most of the environmental problems we have just because of the consequences of technological progress.

In the course of my teaching activities, I determined the range of topics for a school course in physics, where it is imperative to address environmental problems and, as a result, I began a gradual selection of tasks that accumulated as I worked. This is how my "Ecological problem book" was formed. The problem book is divided into sections, coinciding with the main sections of physics. I consider finer fragmentation inappropriate, since for some topics there are only one or two tasks (for example, Measurements). And it is often difficult to clearly see the line between topics, since natural phenomena always occur in connection with each other.

The tasks from the collection, I think, will be useful to teachers working at school. Tasks can be used not only in the classroom, but also in extracurricular activities.

Explanatory note.

Ecology (from other Greek οἶκος - dwelling, dwelling, house, property and λόγος - concept, doctrine, science) is the science of the relationship of living organisms and their communities with each other and with the environment.

Since ancient times, people began to notice various patterns in the interaction of animals with each other and with the environment. However, in those days, even biology was not a separate science, being part of philosophy.

In modern times, which is characterized by an upsurge in the field of scientific knowledge, environmental patterns were identified by encyclopedic scientists, for example: R. Boyle - he conducted one of the first environmental experiments - the effect of atmospheric pressure on animals, resistance to vacuum of aquatic, amphibian and other poikilothermic animals .

Ecology is usually regarded as a sub-branch of biology, the general science of living organisms. Living organisms can be studied at various levels, ranging from individual atoms and molecules to populations, biocenoses, and the biosphere as a whole. Ecology also studies the environment in which they live and its problems. Ecology is related to many other sciences precisely because it studies the organization of living organisms at a very high level, explores the relationship between organisms and their environment. Ecology is closely connected with such sciences as biology, chemistry, mathematics, geography, physics, epidemiology, biogeochemistry. Consider the connection between ecology and physics.

After all, physics and the introduction of its results into industry are presented as one of the main sources of environmental pollution. Indeed, the nuclear industry, energy, and other industries that make extensive use of the achievements of physics provide many examples of the negative impact on the environment.

Physics is a science about nature, therefore, in connection with the growing potential of technological progress and the development of technology that bring an ecological catastrophe, it is necessary to consider the problem of environmental protection in the lessons of this particular subject.

To prevent possible negative consequences of human intervention in nature, it is necessary to solve a number of scientific, technical, socio-political and other problems, among which one of the first places is occupied by pedagogical and educational problems. The younger generation, while still at school, should be prepared for a scientifically based and careful attitude to the natural environment. That is why the idea of ​​forming an ecological culture among schoolchildren has now become extremely important.

Ecological education and upbringing of schoolchildren in the process of teaching physics is connected, first of all, with the formation of their ideas about the integrity of nature, the relationship between the phenomena occurring in it and their causation, about the interaction of man and nature and, as a result, a violation of a certain balance of natural processes. The ecological orientation of teaching physics has been strengthened mainly as a result of consideration of natural phenomena, as well as the impact of human activity on the world around us. This allows schoolchildren to understand more deeply, more fully and more correctly the increasingly complex interaction between society and nature, to be aware of the danger of ill-considered human interference in her life, to be able to navigate the information on the protection and use of natural resources, which they receive from popular science literature. , radio and television programs, can assess the environmental impact of certain technical solutions and use their physical knowledge to actively protect the environment.

In this regard, the object of my work is environmental education in the process of teaching physics. The subject is the means and methods of environmental education.

The purpose of the work: finding ways to solve the problem of environmental education in the educational process, developing a system of means and methods of environmental education. Since there is a problem of environmental education, I set a goal to develop a collection of problems in physics with environmental content for the teacher. The developed material is systematized and divided into separate paragraphs.

The systematic application of the proposed tasks in physics lessons increases the overall level of environmental culture, arouses interest in the subject of physics and the quality of its teaching.

Environmental challenges and questions can be applied to the following topics:

measurements

mechanical movement

Diffusion

Ways to reduce and increase pressure

Communicating vessels

capillary phenomena. Wetting.

Surface tension of liquid

Air shell of the earth

Atmosphere pressure

Pressure of liquids and gases

Sailing ships

Examples of heat transfer in nature and technology

fuel energy

Evaporation

Internal combustion engine

Alternative energy sources

Steam turbine

Electrification of substances

Sources of electric current

Actions of electric current

Electric current power

A magnetic field

Electrical engine

Sources of light

Resonance

Sound sources, sound vibrations

Ultrasound and infrasound

Electromagnetic field

Radioactivity

Nuclear reactor. Nuclear power.

human physics

Mechanics.

A drop of oil with a volume of 0.003 mm 3 spreads over the surface of the water, forming a thin film with an area of ​​300 cm 2 . taking the layer thickness equal to the diameter of 1 molecule - 0.0000001 mm, Estimate what area the spreading oil with a volume of 1 m 3 will occupy.

The leaves, raised by the wind, in 5 minutes, moving evenly, moved to a distance of 7500 m. What is the speed of the hurricane?

The speed of the Earth in orbit around the Sun is 300 times the speed of a racing car racing at a speed of 360 km/h. Calculate from this the length of the earth's orbit and the distance from the earth to the sun.

It has been established that dolphins are very fast. 100 meters, for example, they swim in 10 seconds. Considering that the density of water is 800 times that of air, how can one explain the reason for the high swimming speed of dolphins?

Small marine fish walk in a flock, the external shape of which resembles a drop. Why is this form of flock formed?

What is the importance of the bristles on the surface of the body of an earthworm for its movement?

As you know, some birds during long-distance flights are placed in a chain or a jamb. What is the reason for this arrangement?

What is the purpose of the swimming membranes on the feet of a duck or goose?

Why does strong wind break trees more often in summer than in winter?

Why does oats suffer little from the wind: almost never breaks, does not lie down?

With what force does a corn sprout come out of the soil?

The jumping limbs of a grasshopper are very long. Why?

Why is it impossible to hold the same load in an outstretched hand as in a bent one?

As you know, molars overcome much more resistance than incisors. It is possible, for example, in some cases to crack open a nut that has not succumbed to the influence of the incisors. Explain why?

Why can't turtles rolled over on their backs usually turn over on their own?

When is the center of gravity of a tree higher: in summer or autumn, when the leaves have fallen?

In a dense forest, you can always find trees felled by the wind, and in an open field, where the wind is much stronger, trees rarely fall down. What explains this?

Which of the trees - spruce or pine - is in a more stable position?

How much pressure can a wasp create when it stings?

Many animal and human bones have thickenings at the ends. Explain the purpose of these thickenings?

Beavers are known to often gnaw through thick trees. Why don't beaver teeth get blunt when doing this?

Although the whale lives in water, it breathes with lungs. Despite the presence of lungs, the whale will not live even an hour if it accidentally finds itself on land. Why?

If a deep-sea fish is quickly pulled to the surface of the sea, then its internal organs swell and the fish dies. How can this be explained?

As you know, the suit of a diver working at great depths is constantly pumped with air under high pressure. This air resists the pressure of the water on the suit and prevents the water from flattening it. But the air in the diver's suit presses in all directions with the same force. Consequently, the diver must experience its great pressure, but meanwhile this does not happen. What's the matter here?

Why does a diver experience pain only when he is immersed in or out of water, but not when he is at depth?

An elephant can stay underwater and breathe through a trunk protruding above it. Why, then, when people tried to imitate an elephant, replacing the trunk with a long rubber tube tightly fitting to the mouth, was bleeding from the mouth, nose, ears, ending in a serious illness?

How does an elephant use atmospheric pressure whenever it starts drinking water?

Why can fish breathe oxygen dissolved in water?

Which air is richer in oxygen: the one we breathe or the one that fish breathe?

Why do fish living in an aquarium sometimes swim near the surface of the water?

Most algae have thin, flexible stems. Why don't algae need hard stems?

Calculate what pressure force from the atmosphere is experienced by a person whose body surface is 2 m 2.

Everyone saw in the summer small flies hanging in the air as if motionless. With a jerk, the insects jump to the side and again freeze in place. How can insects remain motionless at one point?

How important is atmospheric pressure for the articulation of bones in our body?

Why is the action of the joints disturbed on high mountains: the limbs do not obey well, dislocations easily occur?

Why does an artilleryman open his mouth when firing from a gun?

In the open seas and oceans there is a very interesting fish stuck. This strange fish attaches itself to various objects, especially sharks and ships, and holds on with such force that it is difficult to tear it off. Due to what forces, stuck attached to a moving object?

Everyone knows that an ordinary fly walks freely on the ceiling. Will she be able to move just as freely along the ceiling in a vacuum?

Due to what force is the mature acorn kept in the "calyx" after the death of the connective tissue?

A cow is an artiodactyl animal, a horse is a one-hoofed animal. When moving through marshy and swampy places, the cow easily raises its legs, and the horse - with great difficulty. Why?

Why, in a river with a muddy bottom, do we get stuck more in a shallow place than in a deep one?

Why can a person whose body is lighter than water drown if he cannot swim, while a horse and other animals immediately begin to swim, even if they have never been in water before?

What role does the swim bladder play in fish?

Why is it that a diving dog easily pulls a drowning person out of the water, but, having dragged him to the shore, cannot even move him from his place?

If you watch waterfowl, you will notice that they sink a little into the water. Explain why?

The seeds of many plants have light wings. What is their purpose?

Some large seabirds often "accompany" ships, chasing them for hours or even days. At the same time, attention is drawn to the fact that these birds overcome the path together with the steamer with a small expenditure of energy, flying with mostly fixed wings. Due to what energy do birds move in this case?

Spider legs do not have muscle fibers. However, the spider not only moves quickly, but even jumps. How can this be explained?

Why does a lone deciduous plant form a large snowdrift in winter, although the snow cover is much thinner throughout the surrounding area? How does this benefit plants?

Why can't a bird that falls into a well fly out of it?

Why does a cat always land on its feet when it falls?

Why does a person, getting into a space where the pressure is much lower than atmospheric pressure, for example, on high mountains, often experience pain in the ears and even in the whole body?

How does the human respiratory apparatus work?

Oil with a volume of 1 m 3 was spilled on the surface of the water. What area will the oil occupy if the layer thickness is assumed to be 1/40,000 mm?

Scientists have calculated that there are 10,000,000 hairs on the root of a wheat stalk that serve the plant for nutrition. What is the total length of these hairs, and what is the cross-sectional area of ​​the hair if its average length is 2 mm and their total volume is 1.5 cm3?

Most cereal plants have a tall tubular stem with a heavy spike at the top. What is the purpose of the tubular stem?

How to determine the density of an unknown liquid using only a glass, water and balance with weights?

When studying the cloud, it was found that the average volume of a water droplet in it is 0.000004 mm 3 . What mass of water is contained in a cloud with a volume of 1 m 3, if a cloud with a volume of 0.1 cm 3 contains an average of 140 droplets?

Coming out of the water, the dog is shaken. What phenomenon helps her in this case to free wool from water? Explain the answer.

A fox, running away from a dog chasing her, often saves herself by making sharp sudden movements to the side just at those moments when the dog is ready to grab her with his teeth. Why is it difficult for a dog to catch a fox?

Why, when weeding, weeds should not be pulled out of the ground too abruptly, even if they are weakly held in the soil?

In what way do some leguminous plants use the property of inertia to spread their seeds?

What is the significance of the elastic hair on the soles of the hare's feet?

Why does a butterfly's wing move slower than a wasp's wing when flying?

How to explain the greater mobility of small animals compared to larger ones?

“Who does not know,” wrote Galileo Galilei, “that a horse, falling from a height of three to four cubits, breaks its legs, while the dog does not suffer, and the cat remains unharmed, being thrown from eight to ten cubits, just like a cricket that has fallen from the top of a tower, or an ant that has fallen to earth even from the lunar sphere.” Why do smaller insects, falling to the ground from a great height, remain unharmed, while large animals die?

Watch the swimming of fish, leeches. How is Newton's third law used in their motion?

Why does a squirrel need a big tail? And the fox?

Why do pike swim faster than other fish in the river?

Why do some fish press their fins when they move fast?

Why is it difficult to hold live fish in your hands?

The fish can move forward by throwing jets of water with its gills. Explain this phenomenon.

What is the purpose of the webbed feet in waterfowl?

The bird sitting on the branch fluttered and flew away. Where and at what point did the branch deviate? Why?

What causes destruction during earthquakes?

A person takes an average of 15 breaths per minute. With each breath, 1600 cm 3 of air enters his lungs. How much air passes through the human lungs in one hour?

Why do large raindrops fall faster than small ones? (take into account the force of air resistance).

From a high cliff, it is safer to jump into loose sandy mounds than onto hard ground. Why?

Why are ships (tankers) intended for transporting oil divided by partitions into separate compartments - tanks?

A motor ship in a collision with a boat can sink it without any damage to itself. How does this fit in with the equality of action and reaction?

In a day, a young bamboo can grow by 86.4 cm. How much will it grow in a second?

Determine the speed of the river in the Volga in the area where the speed of the cargo ship downstream is 600 km/day, and against the current 336 km/day.

Let us assume that the thickness of the ice in the pond increases by an average of 5 mm per day. What will be the thickness of the ice in a week if its initial thickness is 2 cm?

The fox is chasing the hare at such a speed that its momentum is equal to that of the hare. Can the fox catch up with the hare?

Do a bucket of drinking water have the same mass as a bucket filled with sea water?

Why does a bird of prey, falling like a stone from the sky, spread its wings near the ground?

What is the fundamental difference between the way a person and an octopus move in water?

Calculate the water pressure: a) at the greatest depth of the Pacific Ocean - 11035m; b) at the greatest depth of the Sea of ​​\u200b\u200bAzov - 14m (the density of water in it is taken equal to 1020 kg \ m 3)

Why is a projectile explosion under water destructive for organisms living in water?

A storm wind with a force of 10 points creates a pressure of about 1000 Pa on the barrier. Determine the force of pressure on the wall of a house 5 meters high and 10 meters long if the wind blows perpendicular to the surface of the house?

Vessels with an attached bottom are immersed in water to the same depth. The bottom of the vessels disappears if you pour 1 kg of water into each of them. Will the bottom fall off if the water is replaced with mercury?

What role does atmospheric pressure play in drinking?

What force causes the ebb and flow in the seas and oceans of the Earth?

Is a fish in water in a state of weightlessness?

Does gravity act on a swift flying in the air?

The human body can tolerate a fourfold increase in its weight for a relatively long time. What is the maximum acceleration that can be given to a spacecraft when starting from the Earth's surface, so as not to exceed this load on the astronauts' organism? The launch of the spacecraft is considered vertical.

Does the free surface of the ocean repeat the "sphericity" of the Earth?

Why is it impossible to extinguish burning kerosene by pouring water on it?

The ice floe floats in the water. The volume of its above-water part is 20 m 3 . What is the volume of the underwater part?

How would the water level in the ocean change if all the icebergs melted?

What depth in the sea corresponds to a water pressure of 412 kPa?

A hawk, whose mass is 0.4 kg, is lifted by an air stream to a height of 70 m. Determine the work of the force that raised the bird?

The spillway dam of the Volga hydroelectric power station during floods passes every second a volume of water equal to 45,000 m 3. Knowing that the height of the dam is 25 m, determine the power of the water flow.

The water flow in the river is 500 m 3 \s. How powerful is the flow of water if the water level is raised by a dam by 10 m?

Scientists have calculated that a whale, swimming under water at a speed of 27 km / h, develops a power of 150 kW. Determine the force of water resistance to the movement of the whale.

What is the importance of breakwaters (structures in the form of a pier) installed near the coast? The energy of what body is the cause of the destruction of the shore? What is the source of this body's energy?

Determine the kinetic energy of a 50 kg meteorite moving at a speed of 40 km/s.

What is the potential energy of a raindrop with a mass of 20 mg at a height of 2 km?

What is the efficiency of a hydroelectric power plant if the water flow is 6 m 3 \s, the water head is 20 m, and the power of the station is 880 kW?

Determine the useful power of a water engine with an efficiency of 20% if water falls on its blades from a height of 5 meters. The initial speed of the water at this height is 1 m/s. The water leaving the engine has a speed of 2 m / s, and the flow rate of water every second is 2 m 3 / s.

Why do we not hear the roar of powerful processes occurring on the Sun?

Longitudinal or transverse waves are created by a bird in flight with the flapping of its wings?

Even in complete darkness, fish detect the approach of danger with the help of their bodies. What waves "see" the fish?

How do representatives of the fauna of earthquake-prone areas learn about an impending earthquake?

Why, if a person did not see the explosion of a powerful projectile, does the blast wave take him by surprise?

Why did nature endow man with not one, but two organs of hearing - the right and left ear?

It has been established that a bee flying with a bribe (flower juice collected by it) (into the hive) flaps its wings on average 300 times per second, and unloaded - about 440 times per second. Explain how experienced beekeepers recognize by the buzz of bees whether they are flying with prey or fly after it?

Why do we not perceive as sound those air vibrations that are created by the wings of a flying bird?

Why is it quite difficult to determine where the sound is coming from in the forest?

In the coniferous forest, even with a weak wind, a rumble is heard. The forest is noisy, we say then. The noise of the forest arises, mainly, not from the friction of individual needles one against the other. And from what?

How far is the iceberg from the ship if the ultrasonic signal sent by the sonar was received back after 2.8 s? The speed of sound in water is assumed to be 1500 m/s.

In recent years, a lot of cases of bird collisions with turboprop and turbojet aircraft have been recorded. Sometimes it happens that birds just “attack” airports. How can this be explained?

The wings of a bee oscillate at a frequency of 240 Hz. How many wing flaps will a bee make until it reaches a flower field located at a distance of 500 m if it flies at a speed of 4 m/s.

Near the ore deposit, the period of oscillation of the pendulum changed by 0.1%. The density of the ore in the deposit is 8 g/cm 3 . Estimate the radius of the deposit if the average density of the Earth is 5.6 g/cm 3 .

Why don't bats run into obstacles even in total darkness?

Accidentally flying through the window, the bat often sits on people's heads. Why?

Bats' eyesight is known to be very poor, and they navigate only thanks to an ultrasonic locator. With its help, mice locate even the smallest insects with amazing accuracy and catch them on the fly without a miss. But sometimes there are failures. And usually with butterflies. Why doesn't the bat's ultrasonic locator always detect them?

What is the purpose of the two large spherical bubbles located on the sides of the frog's head?

What is the significance of the mobility of the auricles for many animals?:

It is known that at the moment of danger, the round-headed lizard quickly burrows into the ground. How does she do it?

Does the human ear respond to wavelength or frequency?

Determine the maximum and minimum wavelengths perceived by a person. The speed of sound is 340 m/s, the cutoff frequencies are 20 Hz and 20,000 Hz.

Near a straight section of the seashore at a distance L from it

an explosion occurred. Assuming that the bottom of the sea differs little from the inclined plane, find the length of the shore section to which the waves generated by the explosion will reach. Assume that the depth of the sea at the site of the explosion is sufficiently small.

Octopuses, squids, cuttlefish move by throwing out water with force, which they collect through a hole in the mantle. Where in technology is the same principle of motion used?

Molecular physics

Where are more atoms: in a glass of water or in a glass of mercury?

A lake with an average depth of 5 meters and an area of ​​4 km 2 was “salted” by throwing a crystal of table salt weighing 10 mg. After a long time, a glass of water with a volume of 200 cm 3 was scooped up from the lake. How many sodium ions are in this beaker?

At what volume of the sports hall, the number of molecules in the air inside the hall is 100 times greater than the number of atoms in an iron bar with a mass of 100 kg? Consider that the air is under normal conditions.

At room temperature and normal atmospheric pressure, methane leakage in a household gas stove is allowed no more than 1.1∙10 -8 m 3. Determine the number of gas molecules that appeared in the room due to such leakage if the stove was turned on for three hours.

In a room with an area of ​​100 m 3 and a height of 4 m, 1 liter of acetone is poured. How many molecules of acetone are contained in 1 m 3 of air if all the acetone has evaporated and is evenly distributed throughout the room? The chemical formula of acetone (CH) 2 CO.

Explain why kerosene is used to detect through defects in the capillary welding quality control method?

The marine animal squid, when attacked, throws out a dark blue protective liquid. Why, after a while, the space filled with this liquid becomes transparent even in calm water?

A fresh, albeit invisible, track (for example, a hare) the dog takes. However, over time, she cannot smell him. Explain this phenomenon.

Why is a can of kerosene often covered on the outside with a thin layer of kerosene?

Why do we smell flowers from a distance?

If, on a sunny summer day, the temperature of the bare soil and the nearby soil covered with plants is measured, it turns out that the bare soil is heated more strongly. But if in these places the temperature of the soil is measured at night, then, on the contrary, the soil under the plants will have a higher temperature than the bare soil. How can this be explained?

Why do ducks willingly climb into the water in severe frost?

Does a bear's body temperature drop during hibernation?

Lizards and some other small animals that live in the desert climb to the tops of the bushes during the hottest time of the day. Why?

In winter, it is much colder in the wind than in the calm. Will there be a difference in temperature readings?

How do whales, walruses, seals, living in water with eternally floating ice, constantly maintain a high body temperature (38-40 0 C)?

Why don't reindeer freeze even in extreme cold? What protects them from the cold?

Why do small organisms need better protection against heat loss than larger ones?

What is the purpose of bending raspberry bushes to the ground in the northern regions for the winter?

How can one explain that some species of birds (black grouse, capercaillie, hazel grouse, partridge, etc.) burrow into snowdrifts and sometimes spend several days there?

Why do arctic foxes have significantly smaller ears than foxes living in temperate climates?

Why does the water in the sea become warmer after a strong storm?

During the ice drift, it is colder near the river than away from it. Why?

Why is heat more difficult to endure in moist air than in dry air?

Why do winter wheat seeds burrow deeper into the soil than spring wheat seeds?

Why is frost dangerous for plants?

In severe frost, birds often freeze on the fly than sitting still. How can this be explained?

Why do many animals sleep curled up in cold weather?

What is the purpose of the thick subcutaneous fat layer in whales, seals and other animals living in the waters of the polar seas?

Why is there a very large daily temperature range in deserts?

Why do locals in Asian countries wear hats and cotton robes during a heat wave?

What harms plants, especially cereals: heavy snow or snowless winter?

Why do animals living in cold countries have thicker hair than animals living in hot countries?

If a clear night is expected in spring or autumn, gardeners build fires that produce a lot of smoke that envelops the plants. What for?

In severe frost, birds often freeze on the fly than sitting still. Why do you think?

For which plants are the most dangerous spring frosts: for those planted on dark soils or on light ones?

Why is a horse sweating from work covered with a blanket or a fur coat in the cold?

How can you explain why the leaves of many plants curl when drought sets in?

The leaves of most desert plants are covered with dense silvery hairs (wormwood, sand locust, etc.). how does this affect the rate of evaporation of water by plants?

Why do many desert plants have thorns or thorns instead of leaves?

Why, even on cloudy but not rainy days, grass cut in a meadow dries out faster than grass cut in a forest?

After harrowing, the soil evaporates less moisture. Why?

Why does a dog stick out its tongue in extreme heat?

During the volcanic eruption on the island of Krakatoa in Indonesia (1883), a huge amount of the smallest dust was thrown out. Why was this dust in the atmosphere for several years?

If ventilation does not work, the smallest wood dust in the carpentry shop “hangs” in the air for hours even after turning off the woodworking machines. Why?

Why is a cylinder of any compressed gas a great fire hazard?

What pressure must a gas cylinder with a volume of 50 liters withstand in order to store 2 kg of methane (CH 4) at a temperature of 25 0 C?

A bottle filled with gas is tightly closed with a cork with a cross section of 2.5 cm 2 . To what temperature must the gas be heated in order for the cork to fly out of the bottle if the frictional force holding the cork is 12 N? The initial air pressure in the bottle and the external pressure are the same and equal to 100 kPa, and the initial temperature is 3 0 C.

What is the reason for the strong heating and combustion of artificial satellites of the Earth when they enter the lower layers of the atmosphere?

Cars, planes, motorcycles are painted with nitro-lacquer, which gives a smooth, shiny surface. What goal, besides beauty, is pursued in this case?

A match ignites when it is rubbed against the box. It also flares up when placed in a candle flame. What are the similarities and differences between the causes that led to the ignition of the match in both cases?

In late autumn, this phenomenon can be observed. Snow. A day passed, another - warming came - the snow melted. But despite the fact that the frost was -1-2 0 C, many plants remained green. How did they manage to resist? After all, they are 80% water.

Human teeth consist of a hard substance - dentin, and their surface is covered with a layer of even harder, but fragile enamel. Why do teeth deteriorate if you take cold food after hot food and vice versa?

Why does dew on the leaves of many plants collect in drops, and does not spread over the entire leaf?

Some small insects, once under water, cannot get out. What explains this?

On a lake or in a pond, you have probably seen insects more than once - water striders, which, sorting through their long legs, quickly run through the water. They do not swim, but run, touching the water only with the tips of their legs. Explain why their paws do not sink into the water, but rest on it, as on a hard surface?

Why do swallows fly low before rain?

Why do cities where the air is polluted with dust and smoke receive less solar energy?

Why is the temperature of the water in the reservoirs lower than the temperature of the sand on the shore on a summer day? And what happens at night?

Why are air purifying fans usually placed near the ceiling?

Why does ice first appear on the surface in ponds, holes, lakes?

Why is the near-stem circles of the earth near fruit trees covered with layers of peat, manure or sawdust for the winter?

Why is snow retention carried out in the fields in the arid regions of the country not only a good means of accumulating moisture in the soil, but also a means of combating the freezing of winter crops?

Why do sparrows sit “ruffled” in winter?

How are breezes formed?

Why does dirty snow melt faster on sunny days than clean snow?

Which soils are better warmed up by the sun's rays: chernozem or podzolic, having a lighter color?

Why is the water in open reservoirs heated by the sun's rays more slowly than land?

Quartz cookware is durable and never bursts. There is a lot of quartz on Earth. Why not make dishes from quartz?

What are double window frames for? Will the room become warmer in winter if the gap between the frames is significantly increased?

Warm air, as you know, rises. Why is the temperature -50 0 C kept at an altitude of 10 km?

Why does the proximity of water bodies affect air temperature?

Why is the climate of the islands milder than the climate of the interior parts of the continents?

Black grouse in winter, going to bed, falls like a stone from a tree and gets stuck in the snow. What happened to the potential energy of the bird?

It is known that the temperature of motorcycle exhaust gases at the muffler outlet is several times lower than the temperature reached in the engine cylinder. Why?

The specific heat of combustion of pine wood is slightly higher than that of birch wood. Why is it more profitable to buy a cubic meter of birch firewood, and not pine? (We will assume the price of firewood is the same)

What should be done to quickly cool an object by placing it in snow or crushed ice?

To what height could a weight of 1 kg be raised due to the energy released when a glass of boiling water with a volume of 196 cm 3 is cooled to 0 0 C?

A 60 W electric lamp is immersed in a transparent calorimeter containing 600 g of water. In 5 minutes, the water heated up by 4 0 C. What part of the energy consumed by the lamp did the calorimeter pass outside in the form of radiation?

Why do trees crack in severe frosts?

Why are spaceships and rockets provided with refractory metal skins?

Why is dew more abundant after a hot day?

Why are burns with boiling oil always worse than burns with boiling water?

Compare the water temperature at the bottom of a waterfall with its temperature at its top. The height of the waterfall is 60m. assume that all the energy of the falling water is used to heat it.

A 75 W motor rotates the propeller blades inside a calorimeter containing 5 kg of water for 5 minutes. Due to the friction of the propeller blades on the water, the water heats up. Considering that all the heat released during friction went to heat the water, determine by how many degrees it heated up.

A 15 kW engine consumes 15 kg of oil per hour. Determine the efficiency of the machine.

Some installation, developing a power of 30 kW, is cooled by running water flowing through a spiral tube with a cross section of 1 cm 2. In the steady state, running water is heated by 15 0 C. Determine the rate of water flow, assuming that all the energy released during the operation of the installation goes to heat the water.

Why does steam burn more than water of the same temperature?

What kind of firewood - birch, pine or aspen - releases more heat during complete combustion if they are all equally dried and their masses are equal? The specific heat of combustion of aspen is about 1.3∙10 7 J/kg.

Peat, weighing 20 tons, was burned in the boiler furnace of a steam engine. What mass of coal could replace the burnt peat? The specific heat of combustion of peat is taken equal to 1.5∙10 7 J/kg.

How much oil must be burned at a thermal power plant in order to watch an hour and a half film on a 90 W TV? Consider the efficiency of the power plant equal to 35%.

The combustion temperature of some chemical fuel in air at normal pressure is 1500 K. What is the maximum possible efficiency of a heat engine using this fuel? The role of the refrigerator is performed by the ambient air with a temperature of 300K. find the power of the engine if the amount of heat dissipated every second into the surrounding air is 20 kJ.

In the combustion chamber of an engine running on a mixture of oxygen and hydrogen, hot water vapor is formed at a pressure of 8.32·10 7 Pa. The mass of water vapor is 180 g. The volume of the combustion chamber is 0.002 m 3 . determine the maximum efficiency of such an engine if the exhaust vapor temperature is 1000K.

A solar plant has been created at the Kiev Research Institute of Experimental Design to produce hot water for the needs of agricultural complexes. The sun's rays heat the liquid circulating in the solar receiver, which transfers heat to the water supplied to the consumer. The daily capacity of the plant is 3 tons of water heated from 10º to 60ºС. How much firewood is saved in 1 month (30 days) of operation of such an installation?

During 1 hour in the refrigerator it turns into ice at a temperature of 0 0 C, a mass of water of 3.6 kg, which had an initial temperature of 20 0 C. What power is consumed by the refrigerator from the mains if it gives energy of 840 J / s to the surrounding space per unit time?

On a winter road at a snow temperature of -10 0 C, the car skids for 1 minute 6 seconds, developing a power of 12 kW. how much snow will melt when the car slips, if we assume that all the energy released during slipping goes to heat and melt ice.

Would we be able to observe the usual changes in nature in spring if the specific heat of melting of ice would be as small as that of mercury?

Why did the agronomist instruct to water garden crops in the evening, when a message was broadcast on the radio that there would be frosts at night? Explain the answer.

Water in a glass freezes when cooled to 0 0 C. Why, then, in some clouds, which are an accumulation of small droplets of water, water does not freeze even at lower temperatures (for example, at -5 0 C)?

What amount of snow at a temperature of 0 0 С will melt under the wheels of a car if it skids for 20 s, and 50% of all power goes to slipping? The power of the car is 1.7∙10 4 W.

Determine how much coke is required to heat 1.5 tons of scrap iron from 20 0 C to the melting point. The efficiency of the melting furnace is 60%.

Why does water in ponds begin to freeze from the surface?

Why does grass clipping dry faster in windy weather than in calm weather?

When leaving the river after bathing, we feel cold. Why?

Why is a horse covered in a blanket sweating after riding in the cold?

Damp wood burns worse than dry wood. Why?

For 5 days, 5∙10 -2 kg of water completely evaporated. On average, how many molecules are ejected from the surface of the water in 1 second?

How to explain the appearance of frost on window panes in winter? Which side does it appear from?

How to explain the formation of a cloud trail behind a jet aircraft flying at high altitude?

What is the importance of wetting in plant life?

Geysers can be thought of as large underground reservoirs filled with groundwater and heated by the earth's heat. The exit from them to the Earth's surface is carried out through a narrow channel, which in the "calm" period is almost completely filled with water. Assuming that the “active” period begins when water boils in the underground reservoir, and that during the eruption the channel is filled only with steam that is thrown out, estimate what part of the water the geyser reservoir loses during one eruption. Channel depth 90m, heat of water evaporation 2.26∙10 6 J\kg, heat capacity of water 4.2∙10 3 J\(kg∙K)

Why internal combustion engines are not used in a submarine when scuba diving

Does incomplete combustion of fuel in an internal combustion engine affect its efficiency; on the environment?

A car is moving at a speed of 72 km/h. Engine power 600 kW, its efficiency is 30%. Calculate the fuel consumption per 1 km.

The temperature of the gases formed during the combustion of fuel in the cylinders of a car engine, 800 0 С; exhaust gas temperature 80 0 C. Fuel consumption per 100 km at a speed of 90 km / h is 10 -2 m 3; calorific value of fuel 3.2 ∙10 10 J \ m 3. What power could the engine develop if it were an ideal heat engine operating at the highest possible efficiency?

Due to the imperfection of thermal insulation, the refrigerator receives from the air in the room an amount of heat of 420 kJ in 1 hour. The temperature in the room is 20 0 C. What is the minimum power that the refrigerator needs to consume from the network in order to maintain a temperature of -5 0 C inside the refrigerator?

The gas heater consumes 1.2 m 3 of methane (CH 4) per hour. Find the temperature of the heated water if the outflowing jet has a velocity of 0.5 m/s. The jet diameter is 1 cm, the initial temperature of water and gas is 11 0 C. The gas in the tube is under pressure of 1.2 atm. Heater efficiency 60%.

A person feels comfortable at a relative humidity of 40-60%. Why can there be a feeling of exhausting heat at an air temperature of 25 0 and a relative humidity of 80-90%, while at a temperature of 30 0 C and a humidity of 30% one can feel good?

At sea, at an air temperature of 25 0 C, relative humidity is 95%. At what temperature can fog appear?

It's snowing outside. How to determine the percentage of water in it?

Above the sea surface at a temperature of 25 0 C, the relative humidity of the air was 95%. At what temperature can fog appear?

At what air temperature is its relative humidity equal to 50%, if it is known that the water vapor contained in the air goes into saturation at 7 0 C?

In the evening, at an air temperature of 2 0 C, the relative humidity is 60%. Will frost fall at night if the air temperature drops to -3 0 С; up to -4 0 С; up to -5 0 C?

Which air is lighter - dry or humid at the same pressure?

In the capillaries of sandy soils at a temperature of 20 0 C, water rises to a height of 1.5 m. What is the diameter of soil capillaries? Wetting is considered complete .

In a drought, compacted soil dries out strongly, and plowed soil weakly. Why?

In one breath, 0.5 liters of air enters the lungs of a person. how many oxygen molecules are contained in such a volume of air if the proportion of oxygen in it is 20%?

What mass of oil needs to be burned at a thermal power plant in order to watch a 1.5-hour movie on a 250 W TV? Power plant efficiency 35%

electricity and magnetism

Whether the lightning that has arisen between the cloud and the Earth is an electric current; between clouds?

How does an electric field "fight" dust?

Why are flammable objects, such as powder magazines, sometimes covered with a grounded metal mesh?

How to protect workers of a laboratory in which they experiment with large electrostatic charges from the action of the electric field of these charges?

If any conductive body, including a human one, is isolated from the ground, then it can be charged to a high potential. So, with the help of an electrostatic machine, the human body can be charged to a potential of tens of thousands of volts. Does the electric charge placed on the human body in this case affect the nervous system?

Which three types of fish are often referred to as living powerhouses? How great is the tension they create?

Franklin said that by discharging electricity from a battery, he could not kill a wet rat, while a dry rat died instantly from the same discharge. What caused it?

What changes does the current cause in the human body?

Why is the random passage of current through two closely spaced points of the body, for example, two fingers of the same hand, felt not only by these fingers, but by the entire nervous system?

Why is it dangerous to touch high-voltage masts, because current-carrying wires are separated from the masts by whole garlands of insulators?

Lightning most often strikes trees with roots that penetrate deep into the soil. Why?

Centuries-old experience shows that lightning most often strikes tall deciduous trees, mostly standing alone. Therefore, such trees are a good conductor for atmospheric electricity. Why is a person caught in a thunderstorm warned not to hide under the trees? Why does a lightning rod remove lightning from a person, and a tree, on the contrary, attracts it?

There are times when a bird sitting on a power line wire is electrocuted. Under what circumstances can this happen?

The writer B. Zhitkov describes such a case: “Once at the beginning of summer I was riding along the floodplain of the river. The sky was covered with clouds, a thunderstorm was gathering. And suddenly I saw that the tips of the horse's ears began to glow. Now above them formed, as if beams of bluish fire with indistinct outlines. These flames were definitely flowing. Then jets of light ran down the horse's mane and over its head. All this lasted no more than a minute. It began to rain, and the wonderful lights disappeared." Explain this natural phenomenon.

As a rule, street dust, rising in the air, is positively charged. What electrical charge should paint have in order to prevent dust from settling on the walls of buildings?

Draw a table in your notebook: Write down what types of energy are used to produce electric current during operation: a battery, a photocell, a thermal power plant, a hydroelectric power station, a thermoelement, a solar battery, a galvanic cell, a wind turbine.

Mechanical	internal	Chemical	Luminous

1. Is it possible to insert a thick wire or a bundle of copper wires (“bug”) in place of a blown fuse? Why?

   A wind engine is installed on the school building, which rotates the shaft of an electric generator with a power of 0.6 kW. How many 12V, 2A lamps can this wind farm power?

   The current source installed on the bicycle generates current for two lamps, the current in each lamp is 0.28 A at a voltage of 6V. Determine the power of the generator and the work of the current in 2 hours.

   Why does power consumption increase when working on a lathe or drilling machine with an incorrectly sharpened or blunt tool?

   Two trolleybuses with identical electric motors move simultaneously, one at a higher, the other at a lower speed. Which of them has more electric current work, if we assume that the resistance to movement and the time of movement are the same in both cases?

   A wind turbine is installed in the mountain village, which drives an 8 kW electric generator. How many 40 W light bulbs can be powered from this source if 5% of the power is consumed in the supply wires?

   To what value is it necessary to increase the voltage in a power transmission line with a resistance of 36 ohms so that 95% of the electricity is transferred from a power plant with a capacity of 5 MW?

   With what cross-section is it necessary to take a conductor for the construction of a power transmission line from the power plant to the consumer with a total length of 4 km in order to transmit a current of 10 kW to the consumer? Line voltage 300 V, allowable transmission loss 8%

   A power of 62 kW is transmitted from the substation to the consumer. Line resistance 5 ohm. For the cases of transmission at a voltage of 620 V and 6200 V, determine: what power the consumer will receive; consumer voltage.

   At the ends of a two-wire transmission line 175 meters long, AC power is 24 kW at a voltage of 220V. Calculate the power loss in this line if it is made of copper wire with a cross-sectional area of ​​35 mm2.

   What are the causes of power loss in a transformer?

   Why is a massive chain attached to the body of a tank truck designed to transport gasoline, several links of which are dragged along the ground?

   Propose a design of an installation that allows, with the help of an electric field, to collect dust and smoke.

   Why does the lower end of the lightning rod need to be buried deeper, where the layers of the earth are always wet?

   Why can birds sit safely on high voltage power lines?

   Why is it possible for a person to be electrocuted in damp rooms even if he touches the glass bulb of an electric light bulb?

   Why is it necessary to immediately turn off the breaker in the event of a fire in electrical installations?

   Why is it impossible to extinguish a fire caused by electric current, water or a conventional fire extinguisher, but it is necessary to use dry sand or a sandblast fire extinguisher?

   What effect of electric current do we encounter when ozone is formed in the air during lightning discharges?

   Why is it recommended to stand on one leg near the place where a broken high-voltage wire touches the ground?

   In one of his works, the famous Russian writer V.K. Arseniev describes the behavior of ball lightning slowly floating through the air in this way: "... the ball avoids contact with tree branches in every possible way, bypasses every knot, every twig or blade of grass." Explain the reasons for this movement.

   To clean the air from dust in some industries, electrostatic filters are used. These filters create a highly inhomogeneous field. Are all dust particles attracted to the electrode with the highest field strength?

   The lightning observed in nature is characterized by the following average values: current strength 15 kA, potential difference (between two clouds or a cloud and the Earth) 10 5 V, duration 0.02 sec. The number of lightning on the entire globe reaches an average of 100 lightning per second. Based on these data, estimate the average power of one lightning and all lightnings together. Compare the latter value with the power of the Krasnoyarsk hydroelectric power station - one of the largest stations in the world 5∙10 6 kW.

   What is the electrical capacity of the Earth? The radius of the Earth is 6400 km.

   Why is the screen of a working TV covered in dust more than all other bodies in the room?

   Why can fuses in the lighting network sometimes melt close to the place of a lightning strike and damage sensitive electrical measuring instruments?

   Why do incandescent bulbs most often burn out when turned on and very rarely when turned off?

   In the work of the French physicist Arago "Thunder and Lightning" there are many cases of remagnetization of the compass needle, magnetization of steel objects by the action of lightning. How can these phenomena be explained?

   The wires caught fire due to a short circuit. Why can't they be extinguished with water or a fire extinguisher until the area on fire is disconnected from the network?

   Why, on electrified railways, is the positive pole of the voltage source connected to the overhead wire, and the negative pole to the rails?

   How much electricity must be spent to obtain hydrogen from water with a volume of 2.5 liters at a temperature of 25 0 C and a pressure of 10 5 Pa, if the electrolysis is carried out at a voltage of 5 V, and the efficiency of the installation is 75%?

   Why are wires of the largest possible diameter used to reduce electricity losses due to corona discharge in high voltage power lines? Why does the loss of electrical energy for a corona discharge increase sharply in bad weather - heavy fogs, rains and snowfalls?

   How many times does the energy loss in the power line decrease when the voltage rises 50 times?

   How can an accident associated with the burnout of the winding of a superconducting solenoid be avoided?

   Why does the presence of a very high voltage in the secondary winding of a step-up transformer not lead to large energy losses in the winding itself?

   Why does power consumption increase with increasing load (reducing resistance) in the secondary circuit of a transformer?

   On what frequency do ships transmit an SOS distress signal if the wavelength is 600m by international agreement?

   How can people be protected from the harmful effects of external electric fields?

   Which human organs create a magnetic field around them?

   As you know, bats navigate in space by means of ultrasound. What animals do you know that would navigate in space using electromagnetic waves?

Optics.

What effect of light causes the formation of chlorophyll in the leaves of plants, the tanning of the human body and the darkening of photographic film?

Give an example of the chemical action of light on a physical body.

Give an example showing that objects that are exposed to light heat up.

Name the effects of light on physical bodies known to you.

Why do students have to sit in classrooms with windows on the left?

On a sunny day, the length of the shadow on the ground from a Christmas tree 1.8 m high is 90 cm, and from a birch - 10 m. What is the height of the birch?

Why can you look at fluorescent lamps calmly: they do not “cut” your eyes?

It is dangerous to photograph a tiger from a distance of less than 20 m. What size can a camera obscura with a hole of 1 mm in diameter be, so that the tiger in the photo is striped? The distance between the stripes on the skin of a tiger is 20 cm.

To observe marine animals, a porthole was made in the bottom of the vessel, the diameter of which is 40 cm much larger than the thickness of the glass. Determine the bottom viewing area from this porthole if the distance from it to the bottom is 5 m. the refractive index of water is 1.4.

The illumination of the workplace for jewelry work, according to the standards, should be at least 100 lux. At what minimum height from the workplace should a lamp with a luminous intensity of 100 cd be placed?

What harm on a sunny day can droplets of water that have fallen on them cause to the leaves of plants?

Sometimes the lens is referred to as "fire glass". To which lenses, this name cannot be applied? Why?

In the early morning, the Sun, reflected from the surface of calm water, blinds the eyes, and at noon, the image of the Sun in the water can be viewed even without dark glasses. Why?

Why do dragonfly wings have iridescent colors?

Explain the causes of a double rainbow. What is the alternation of colors in the first (primary) and second rainbow?

In hot deserts, a mirage is sometimes observed: in the distance, the surface of a reservoir “emerges”. What physical phenomena cause such a mirage?

The sensitivity of the retina to yellow light with a wavelength of 600 nm is 1.7·10 -18 W. How many photons must fall each second on the retina for light to be perceived?

The higher the voltage applied to the X-ray tube, the harder (ie shorter wavelength) beams it emits. Why? Will the radiation hardness change if, without changing the anode voltage, we change the incandescence of the cathode filament?

If you look from the shore at the fish swimming in the river, then often, even knowing this fish, you can make a mistake in its name. Errors are especially common when the fish is wide and flat: its vertical dimensions are somewhat reduced, while the horizontal ones remain unchanged. For example, a bream does not seem so flat in the water, and it is easy to mistake it for another fish. How do you explain this?

Explain from the point of view of optics the expression "All cats are gray at night"

Why, if you dive under water, all objects seem blurry with unclear contours, and very small objects are not visible at all?

There are organisms (for example, the larva of a feathery mosquito), which are not visible in the water due to transparency. But the eyes of such invisible creatures are clearly visible in the form of black dots. Why are these creatures not visible in the water? Why are the eyes not transparent? Will they remain invisible in the transparent air?

A curious four-eyed fish lives in the coastal waters of North and South America. Each of her eyes is divided into two halves - two pupils, but one lens. Why does a fish have such an eye structure?

Pupils in horses are located horizontally, while in cats and foxes, on the contrary, they are located vertically. Explain why?

As you know, with the onset of darkness, chickens completely cease to see, and owls, on the contrary, can use their eyesight only from that moment - they do not see anything during the day. Do you know what explains the peculiarities of vision of these birds.

Is it correct to say that the hare, without turning its head, sees objects behind it?

Why can a falcon see at a great distance?

Why are most of the inhabitants of the Far North white, and those whose color is different, for example, a squirrel, a hare, change it to white in winter?

Why are insects living in the polar regions and highlands predominantly dark in color?

In the dense spruce forest there are no red, no blue, no yellow flowers, only white or pale pink. What explains this?

What coloration of fish helps them to camouflage themselves from enemies?

Nuclear physics.

Why is natural uranium not a nuclear fuel, and why is its storage not associated with the danger of an explosion?

Why are radioactive preparations stored in closed thick-walled containers? In lead containers?

Deposits of radioactive elements are always accompanied by lead. It is known that the thorium series ends with the lead isotope 208 Pb (232 Th → 208 Pb). Assuming the age of thorium ore to be 4·10 9 years (on the order of the age of the solar system), determine the mass of lead that appeared in this ore from thorium weighing 1 kg.

The submarine "Nautilus" (USA) has a fuel plant capacity of 14.7 MW, an efficiency of 25%. The fuel is enriched uranium with a mass of 1 kg, during the fission of the nuclei of which an energy of 6.9 10 13 J is released. Determine the supply of fuel necessary for the annual navigation of the boat.

The average absorbed dose of radiation by an employee working with an X-ray machine is 7 µGy per hour. Is it dangerous to work an employee for 200 days a year for 6 hours a day if the maximum allowable radiation dose is 50 mGy per year?

Why is natural uranium not a nuclear fuel and why is its storage not associated with an explosion hazard?

In the explosion of an atomic bomb (M = 1 kg of plutonium 242 Pu), one radioactive particle is produced for each atom of plutonium. Assuming that the winds evenly mix these particles in the atmosphere, calculate the number of radioactive particles entering a volume of 1 dm 3 of air near the Earth's surface. The radius of the Earth is taken equal to 6∙10 6 m.

BIBLIOGRAPHY.

L.A. Kirik. Mechanics. Pressure of liquids and gases. 7th grade. Independent and control work. Ileksa. Gymnasium. Moscow-Kharkov. 1998

L.A. Kirik. MKT. Properties of gases. Thermodynamics. Vapors, liquids and solids. Grade 10. Independent and control works of Ileks. Gymnasium. Moscow-Kharkov. 1998

L.A. Kirik. electricity and magnetism. 10 - 11 class. Independent and control works of Ileks. Gymnasium. Moscow-Kharkov. 1998

L.E. Gendenstein; L.A. Kirik. THEM. Gelfgat. Solutions of key problems in physics for the basic school. Ileksa. Moscow. 2005

V.I.Lukashik. Physics Olympiad. Moscow. Education. 1987.

I.Sh.Slobodetsky, V.A.Orlov. All-Union Physics Olympiads. Moscow. Education. 1982

3800 tasks for schoolchildren and university applicants. Moscow. Bustard. 2000

I.M.Varikash., B.A.Kimbar, V.M.Varikash. Physics in wildlife. People's light." Minsk., 1967

A.V. Peryshkin. Collection of problems in physics for the textbooks of A.V. Peryshkin "Physics - 7,8,9". Moscow. Exam. 2006.

IN AND. Lukashik, E.V. Ivanova. Collection of problems in physics 7-9 cells. Moscow. Enlightenment, 2005

Answers and solutions.

Dear colleagues! In this section, in addition to answers and solutions to problems, you will undoubtedly find many interesting facts that will help you in your future work.

Mechanics.

4. People have long tried to understand why dolphins and whales swim fast, but only recently it was possible to establish that the speed of these animals depends on the shape of their body. Shipbuilders, taking this into account, built an ocean-going ship not of a knife-like shape, which all modern ships have, but of a cetacean. The new vessel turned out to be more economical, its engine power is 25% less, and the speed and carrying capacity are the same as those of conventional vessels. In addition, the speed of movement of these animals depends on the structure of their skin. Its upper layer, very thick and elastic, is connected with another layer of the skin, in which there are processes. These processes enter the cells of the upper layer, and the dolphin skin becomes even more elastic. With a sharp increase in speed, "velocity folds" appear on the dolphin's skin and laminar flow (flow in layers) does not turn into turbulent (disordered). The traveling wave on the dolphin's skin dampens the turbulence.

5. Oncoming water acts on individual fish in such a way that the movement of each of them can be facilitated or difficult, depending on the position in relation to the flock. This factor determines the drop-shaped shape of a moving flock of fish, in which the resistance of water to the movement of the flock is the least.

6. Adaptations are very common among animals, due to which friction is small when moving in one direction and large when moving in the opposite direction. The bristles of the earthworm, freely passing the body forward and strongly inhibiting the reverse movement, make it possible for the worm to crawl. When the body is lengthened, the head part moves forward, while the tail part remains in place; during contraction, the head part is delayed, and the tail part is pulled up to it.

7. The strongest bird flies ahead. Air flows around her body like water flows around the nose and keel of a ship. This flow explains the acute angle of the jamb. Within a given angle the birds move forward, they instinctively guess the minimum of resistance and feel if each of them is in the correct position relative to the lead bird. The arrangement of birds in a chain is also explained by another important reason. The beat of the wings of the front bird creates an air wave that carries some energy and facilitates the movement of the wings of the weakest birds, usually flying behind. Thus, birds flying in a school or chain are interconnected by an air wave and the work of their wings is performed in resonance. This is confirmed by the fact that if you connect the ends of the wings of birds at a certain point in time with an imaginary line, you get a sinusoid.

8. To move forward quickly, you need to throw back a large amount of water, so the swimming limbs are almost always wide and flat. When the paw moves forward, the membrane bends and the paw feels little resistance; when the paw moves backward, the animal scoops up a sufficient amount of water and quickly moves forward itself.

9. Foliage significantly increases the frontal surface of the tree, and in connection with this, the effective force of the wind also increases.

10. An ear of oats assumes a position in which it provides the least resistance to the wind, the ears turn in the direction of the wind and turn their bases towards it.

11. The tiny green sprout experiences the greatest resistance near the soil crust. To break through its sprout develops a force equal to 0.25 kg.

12. The body acquires a greater supply of energy if the force applied to it acts for a long time or at a sufficiently large distance, for example, a run before a jump, a swing before a blow. The muscles of the grasshopper cannot develop great efforts, therefore, to increase the range of the jump, which requires a significant accumulation of energy, the long limbs of the grasshopper serve.

13. When the arm is extended, the direction of action of the muscle force makes a small angle with the longitudinal axis of the lever. In this case, to hold the same load as with a bent arm, you need to significantly increase muscle effort. With the same muscular effort, a much smaller load can be held with an outstretched arm.

14. By shifting the nut towards the molars, we reduce the lever arm in relation to the transverse axis around which the lower jaw rotates. Thus, the moment of resistance force becomes less than the moment of rotation of the force of the muscles that lift the lower jaw (temporal, chewing, etc.)

15. An inverted turtle is like a heavy spherical segment lying on a convex surface. Such a segment is very stable and in order to turn it over it is necessary to raise its center of gravity high enough. Many turtles cannot raise their center of gravity high enough to roll over and therefore die upside down.

16. The center of gravity of a tree is somewhat higher in summer, when there are a lot of leaves on the trees. Therefore, deciduous trees are in a less stable position than in late autumn or winter, and summer winds often break them or turn them upside down.

17. In the shade of the forest, the lower branches of trees die off and the crown is at the top. The center of gravity of the tree also shifts upward, and it becomes less stable. A tree growing in an open area has a lower crown. The center of gravity of such a tree lies closer to the roots, and it better resists the pressure of the wind.

18. Spruce grows in damp soil, and its roots find enough moisture near the surface. They scatter widely around the tree, but do not penetrate deep into. Pine growing in dry places is forced to seek water at great depths. Its roots go very deep into the ground, so it is more stable.

19. A wasp sticks a sting with a force of only 1 mg, but its sting is very sharp, the area of ​​\u200b\u200bits tip is 0.000 000 000 003 cm 2. so the wasp can create tremendous pressure.

20. When a homogeneous body is compressed, the amount of deformation at all its points will be the same, except for the ends where the body rests on other bodies. The fact is that the deformable body does not come into contact with the support and other bodies with all its points, so the pressure at the ends of the deformable body will be greater than inside it. In order for the pressure to be equal at all points, its ends must have a large cross-sectional area. This explains the presence of thickening on some bones of the human and animal skeleton.

21. Beaver tooth consists of several layers of different hardness. When a beaver gnaws at a tree, the strong enamel that covers the top of the tooth is under more stress, while the rest of the relatively soft tissue is less. As a result, the entire tooth is ground evenly and the angle of sharpening remains unchanged. The work of self-sharpening tools is based on this principle.

22. The weight of a whale reaches 90-100 tons. In water, this weight is partially balanced by the buoyancy force. On land, under the influence of a huge weight, the whale's blood vessels are compressed, breathing stops and it dies.

23. At great depths of the sea, there is a large hydrostatic pressure, which is balanced by the internal pressure in the body of the fish. If the fish is on the surface of the sea, then the pressure in the body will not be balanced by external pressure, so the fish swells, its internal organs burst and the fish dies.

24. The diver does not experience this pressure because he breathes the air supplied to the diving suit, and the air pressure on his body from the outside is balanced by the air pressure from the inside.

25. During the diver's lowering into or out of the water, the balance between the external pressure and the pressure in the diver's body organs is disturbed. In addition, with a sharp rise from the water to the surface, the external pressure quickly drops, the gases dissolved in the body fluids begin to quickly release, leading to clogging of small blood vessels with air bubbles. To avoid this, divers in rubber suits usually descend to a depth of no more than 50 m, and their rise is carried out slowly.

26. In the chest cavity of a person immersed in water with a tube, in his lungs and on the surface of the heart, the pressure of outside air dominates. On the surface of the body, hydrostatic pressure additionally acts, depending on the depth of immersion. Therefore, even at a shallow depth, such a force will act on the chest that the muscles will not be able to overcome it and expand the lungs for inspiration. Hydrostatic pressure also impairs blood circulation. Bleeding from the ears is explained by the fact that under the influence of excess hydrostatic pressure, blood enters the tympanic cavity, where there is a lower pressure than on the surface of the body. The elephant has very strong muscles, so even a long stay under water does not harm him.

27. The elephant's neck is short, and he cannot bend his head towards the water, as other animals do. An elephant lowers its trunk into the water and draws in air. At the same time, due to external atmospheric pressure, water enters the trunk. When the trunk is filled with water, the elephant bends it and pours the water into his mouth.

28. Any gas tends to move from the place where there is more pressure to the neighboring space, where the pressure is less. In the blood of fish, the pressure of oxygen is less than its pressure in water, so oxygen passes from the water into the blood. Flowing through the blood capillaries of the gills.

29. The air we breathe contains 21% oxygen. It has been established that twice as much oxygen dissolves in water as nitrogen, which leads to the enrichment of air with oxygen: air dissolved in water contains about 34% oxygen.

30. Fish breathe oxygen dissolved in water. When there is little oxygen in the water, they rise to the surface, which is in contact with the air, where there is more oxygen.

31. Underwater plants do not need hard stems, as they are supported by the buoyancy of water. In addition, if such plants had a hard stem, then water during unrest could break them.

32. A force of approximately 1 kN acts on each square centimeter, and the total force acting on the surface of the entire body will be approximately equal to 20,000 kN.

34. Everyone knows Guericke's experience with the hemispheres. In this experiment, obviously, nothing would have changed if the hemispheres had been nested one into the other. In the absence of air between the walls of the hemispheres, it would also be impossible to separate them. Similar to such nested hemispheres are the hip joints that connect the lower limbs to the pelvis. Due to the absence of air between the mirror-smooth surfaces, atmospheric pressure firmly presses the joints together. In order to separate them, as in the experiment with the Magdeburg hemispheres, a significant force must be applied.

35. Atmospheric pressure contributes to a tighter fit of the joints to each other. With a decrease in pressure when climbing high mountains, the connection between the bones in the joints decreases, as a result, the limbs do not obey well, and dislocations easily occur.

36. So that the pressure on the eardrum from the inside becomes equal to the pressure from the outside.

37. A modified fin stuck on the back of the fish turned into a sucker. The action of this suction cup is similar to that of a toy gun that shoots with a rubber-tipped stick. When the stick hits the rubber tip against the wall, the rubber flattens out, and then, due to the forces of elasticity, again takes a concave shape. A rarefied space is formed between the wall and the rubber suction cup, since part of the air was forced out from there during the impact. Therefore, under the action of atmospheric pressure, the stick firmly “sticks” to the wall. The action of the fish sticking is carried out by the contraction of the muscles of the fish. Suckers are extremely common in the animal kingdom. For example, cuttlefish and octopuses have a series of tentacles with numerous suction cups, with which they attach themselves to various objects.

38. No, he can't. When moving along the ceiling, the fly is held by atmospheric pressure. It has small suction cups at the ends of its legs.

39. Due to atmospheric pressure.

40. When a horse pulls its legs out of the viscous soil, a reduced pressure is created under the hooves and the external atmospheric pressure makes it difficult to move the legs. In artiodactyl animals, when pressing on the soil, the hooves split in two, and when the legs are pulled out, they approach each other and air passes freely around them.

41. Plunging to a greater depth, we displace a greater volume of water. According to the law of Archimedes, a large buoyant force will act on us in this case.

42. In a horse and other animals, the nostrils are located at the highest point of the body, and therefore, even without moving the legs, they do not choke.

43. The swim bladder is a kind of device that regulates the specific gravity of the fish when it moves to a particular depth. With the help of the swim bladder, fish maintain balance in the water. Going into the depths, the fish keeps the volume of the swim bladder constant. It maintains a pressure in it equal to the pressure of the surrounding water, for which it continuously pumps oxygen from the blood into the bladder. When ascending, on the contrary, the blood intensively absorbs oxygen from the swim bladder. Such pumping and absorption are rather slow, therefore, when the fish is quickly pulled out of a great depth, oxygen does not have time to dissolve in the blood and the inflating bubble breaks the fish. Conger eels have a safety valve for this purpose: when they rise quickly, it opens and releases gas from the bladder.

44. In water, due to the action of the buoyancy force, the sinking person has a small weight.

45. a thick layer of down and feathers that covers the body of a waterfowl, does not let water through and contains a significant amount of air. Due to this, the body of a bird in the water has a small specific gravity and does not sink deep into the water.

46. ​​Thanks to the wings, the seeds are picked up by the wind and carried over long distances.

47. When elucidating this phenomenon, it was found that in calm soaring birds keep somewhat behind the vessel, and in the wind - closer to the leeward side. It was also noticed that if a bird lagged behind the ship, for example, hunting for fish, then, catching up with the steamer, it mostly had to vigorously flap its wings. All these riddles have found a simple explanation: over the steamer, from the operation of the machines, flows of ascending warm air are formed, which perfectly keep the birds at a certain height. Birds unmistakably choose for themselves, relative to the ship and the wind, the location where the updrafts from the steam engines are greatest. This enables the bird to travel using the power of the steamer.

47. It has been established that the limbs act like a hydraulic actuator, the fluid for which blood is compressed.

49. Snow-carrying jets of air during the wind do not bypass the bush, but penetrate it. When jets flow around individual stems, local turbulences occur, the pressure decreases and snow particles are drawn into the bush. In winter, a snowdrift protects the bush from freezing, and in spring the plant receives more moisture.

50. The bird does not rise up in an inclined line or vertically, it takes off only in a spiral, therefore, having fallen into the well, it cannot fly out of it.

51. No matter how the cat falls, it always gets on 4 paws. It has to do with momentum. A falling cat presses its paws and tail to itself, thereby speeding up the rotation. As soon as she takes the position with her paws down, she abducts her limbs, the rotation stops and the cat falls on her paws.

52. This is explained by the fact that in the human body there are a number of cavities containing air, for example, the intestines, the middle ear, the frontal and upper jaw bones. The air pressure in these cavities is equal to atmospheric pressure. When the external pressure on the human body decreases rapidly, the air inside us begins to expand, putting pressure on various organs and causing pain.

53. An example of the use of atmospheric pressure in human life is the breathing apparatus. The chest cavity is separated from the abdominal cavity by a convex septum - the diaphragm. With the contraction of the inspiratory muscles of the chest and the muscles of the diaphragm, the volume of the chest increases, the air in the lungs expands, and the pressure drops. At this time, under the influence of atmospheric pressure, outside air enters the lungs - inspiration occurs. On the contrary, with the contraction of the inhalatory muscles of the chest, its volume decreases, the air in the lungs is compressed, its pressure becomes higher than atmospheric, and exhalation occurs. The breathing apparatus works on the principle of a suction pump.

55.20 km; 0.000075 mm2

56. Bending is always accompanied by stretching of the material on the convex side and compression on the outside. The middle part of the object does not experience any noticeable deformation. The peculiarity of the tubular stem of cereal plants is that it is strong enough, and very little material went into it, so that the plant could develop and grow in the shortest possible time.

57. Hint: First you need to determine the mass of the glass. Then fill it with water and put it back on the scales. According to the density and mass of vodzha in a glass, its capacity is determined. After filling the glass with an unknown liquid, determine the mass on the scales. Knowing the mass of the liquid in the glass and its volume, calculate the density of the liquid.

58. 5.5 kg. Given that 0.1 cm 3 \u003d 100mm 3, from the proportion

, we find that a cloud with a volume of 1 m 3 contains 14∙10 8 droplets. Their volume will be equal to V \u003d 4 ∙ 10 -6 ∙ 14 ∙ 10 0 \u003d 56 ∙ 10 2 (mm 3), or 5.6 cm 3. therefore, the mass of water in a cloud with a volume of 1 cm 3 \u003d 1
=5.6 g

59. Law of inertia .

60. When a fox suddenly changes direction, the dog cannot follow it, because by inertia the dog will move in the original direction for some time.

61. With a sharp pulling out of a plant, its roots do not have time to set in motion and the stem breaks. The roots of weeds remaining in the soil quickly germinate again.

62. Ripe pods of leguminous plants, opening quickly, describe arcs. At this time, the seeds, breaking away from the places of attachment, by inertia move tangentially to the sides.

63. Elastic hair on the soles of the feet of a hare lengthens the braking time when jumping and therefore weakens the force of impact.

65. In the body of an animal, strength is created by muscles. Consequently, the mobility of the animal is the greater, the greater the muscle strength and the smaller its mass (
). The force developed by a muscle is directly proportional to the cross-sectional area of ​​the muscle incision. Therefore, with a decrease in muscle in n as the force decreases n 2 once, while the weight of the muscle, depending on its volume decreases by about n 3 once. Thus, with a decrease in the size of the body of an animal, its strength decreases more slowly than its weight.

66. The weight of an animal is directly proportional to the cube of its linear dimensions, and the surface is directly proportional to the square of its linear dimensions. Consequently, as the size of the body decreases, its volume decreases much faster than the surface. The resistance to movement in air depends on the surface of the falling body. Therefore, small animals experience more resistance than large ones, since they have a large surface area per unit of weight. In addition, when a body of small volume hits an obstacle, all its parts stop moving at once, and during the impact they do not put pressure on each other. When a large animal falls, the lower parts of its body stop their movement upon impact, while the upper ones continue to move and exert strong pressure on the lower ones. This is the concussion, which is disastrous for large animals.

67. These animals in the process of movement throw water back, and they themselves, according to Newton's third law, move forward. A swimming leech drives water back with wave-like bends of the body, a swimming fish with a wave of its tail.

68. Squirrel makes big jumps from tree to tree. The tail helps her: it serves as a kind of stabilizer. The fox's tail helps it make sharp turns when running fast. This is a kind of air steering wheel.

69. The pointed shape of the pike's head experiences little water resistance, so the pike swims very quickly.

70. To reduce the resistance to movement.

71. The friction of the fish on the hands is small, so it slips out of the hands.

76.540l; ≈0.7 kg.

82. 5.5 km / h. Let us denote the speed of the ship in still water relative to the coast through v 1, and the speed of the river flow through v. Then the speed of the ship downstream will be v 1 +v against the current v 1 -v. From the condition of the problem v 1 + v = 600 km/day, and v 1 -v=336 km/day. The joint solution of these equations gives a value of 5.5 km / h

84. No. The mass of the fox is greater, which means the speed is less. The distance will increase.

88. 1.11∙10 8 Pa; 0.26∙10 6 Pa.

92. The bottom of the vessels is held by the force of water pressure from below, and disappears when this force is equal to the force of pressure on the bottom of the vessel from above. The pressure of a liquid depends on its density. ρ rt ρ in, then the bottom of the vessel will fall off.

93. When we drink, we create an area of ​​low air pressure under the lips above the surface of the water. Due to atmospheric pressure, water rushes into this area and enters our mouths.

99. Water will sink down and will not close the access of air necessary for combustion to kerosene.

104. ≈11 million kW

105. 5∙10 4 kW

108.4∙10 10 J

111. N gender =

114. Elastic longitudinal waves, both caused by other marine life and waves reflected from obstacles, caused by the own movement of the fish.

116. The elastic surface of the wave propagates in the earth's crust. It is possible to register not only the fact itself, but also the location of the test using several sensors installed at various points.

117. The sound from the explosion of a projectile will reach a person later than the blast wave, since the speed of the blast wave is much greater than the speed of sound.

118. For an approximate determination of the direction of sound waves

According to the phase difference of oscillations and the sound wave.

119. The wings of a loaded bee make a sound of a lower tone than an unloaded one.

120. The frequency of vibrations created by the wings of a bird is below our threshold of hearing, therefore we do not perceive the singing of a bird as a sound.

121. In the forest, the ear perceives sounds that come not only directly from their source, but also those that come from outside, reflected from the trees. These reflected sounds make it difficult to determine the right direction to the sounding object.

122. Noise arises from the fact that jets of air, bending around branches and needles, form small whirlwinds behind them, emitting a weak hissing sound. Merging together, these weak sounds form the strong noise of the forest.

124. Some birds are attracted to airports by the high-pitched sounds of running turbines, which have frequencies and wavelengths similar to those produced by many animals.

126.

127. Bats make a variety of sounds, but almost all of them fall into the frequency range that lies above the human hearing threshold. During the flight, the bat continuously irradiates the space in front of it with ultrasonic pulses. If an obstacle is encountered on the path of an ultrasonic wave, then a reflection occurs from it - an echo, which is perceived by the animal. Bats use echoes to detect small moving objects that are not visible to them. They use the echo not only for orientation, but also for finding food for themselves. Echo sounders and various kinds of flaw detectors operate on the principle of an ultrasonic locator of mice.

128. Hair absorbs the ultrasound emitted by a bat, so the mouse, not perceiving reflected waves, does not feel obstacles and flies straight at the head.

129. It turned out that some butterflies in the abdominal cavity have a special organ that warns them of the approach of a bat. When a mouse flies out to hunt after dark, it starts locating the surrounding space, these butterflies instantly pick up ultrasonic impulses, and making a sharp turn, they plan to the ground to get out of the field of radiation of predators.

130. The spherical bubbles of a frog, which swell when they cry, are a kind of resonators. They serve to amplify the sound.

131. Due to the mobility of the auricles, animals are able to determine the direction in which the sound source is located.

132. A round-headed lizard at the moment of danger stands on its tail, begins to vibrate and as a result quickly sinks into the ground.

133. to the frequency.

134. 17m and 1.7∙10 -4 m

137.
. There are more molecules in a glass of mercury.

Molecular physics.

143. As a result of diffusion, the protective substance dissolves over time over the volume occupied by water.

146. Flowers contain aromatic substances whose molecules diffuse into the air.

147. Plants retain a significant part of the sun's rays, so the soil under them during the day heats up less than the bare soil under them. At night, when the air temperature drops significantly, plants protect the soil from intense radiation and it does not cool as much as bare soil.

148. The temperature of the water in severe frost is much higher than the temperature of the surrounding air, so the bird will cool less in the water than in the air.

149. Yes, because his breathing and blood circulation almost stop.

150. During the hot time of the day, sand in deserts heats up so much that even at a height of 5 cm from its surface, the temperature is several degrees lower.

151. During frosts, the heaviest, coldest air flows into low places.

152. Both in the wind and in calm, the readings of the thermometer will be the same, since the air temperature is the same, but a person is warmer in calm because the layer of air adjacent directly to our body heats up its heat and protects it from further cooling. In case of wind, such a layer cannot be retained, and cold air flows around the skin all the time, greatly cooling it.

153. These animals have a subcutaneous fat layer that prevents rapid heat loss (because fat is a poor conductor of heat).

154. It turns out that a deer has inflatable wool, hollow hairs are filled with air. Since air does not conduct heat well, such wool protects the deer well from the cold.

155. Loss of heat always occurs from the surface. The storage of heat in the body is proportional to the volume of the body. As the size of the body decreases, the surface decreases more slowly than the volume, so small organisms are less “economical” in retaining heat than large ones.

156. Snow cover protects raspberries from freezing.

157. Snow is a poor conductor of heat, therefore snow cover during severe frosts and snowstorms protects birds from freezing.

158. This is explained by the fact that the ears of foxes are organs that remove heat from the body. Since it is necessary to reduce heat transfer in the north, in the process of biological selection, foxes with small ears are most adapted to life in the far north.

162. So that the seeds do not freeze.

163. Ice, compared to snow, conducts heat about 20 times better, so plants freeze under the ice crust.

164. During flight, the plumage of a bird is compressed and contains little air, and as a result of rapid movement in cold air, increased heat transfer to the surrounding space occurs. This heat loss is so great that the bird freezes in flight.

165. Coagulating, animals significantly reduce the outer surface of the body, which leads to a decrease in heat transfer.

169. In a snowless winter, plants can freeze. Snow cover is a poor conductor of heat and therefore contributes to maintaining a higher temperature in the soil.

170. Thicker animal hair reduces heat transfer to the environment, which is especially important in the conditions of the Far North.

172. During flight, the plumage of a bird is compressed and contains little air, and as a result of rapid movement in cold air, increased heat transfer to the surrounding space occurs. This heat loss is so great that the bird freezes in flight.

173. Spring frosts are most dangerous for plants planted on dark soils, since they have more thermal radiation than light soils, and, consequently, they cool more.

174. A sweaty horse loses a lot of heat to evaporation, which can lead to colds.

175. Leaves have many stomata on the underside. To reduce the evaporation of moisture, the sheet is twisted. Its lower side is less heated by the sun, and therefore less evaporates moisture.

176. Hairs on the leaves of plants prevent the movement of air near the surface of the leaves, thereby they retain the formed vapors and help to slow down the evaporation of moisture from the surface of the leaves.

177. Thorns and thorns, which replace the leaves of many plants, help these plants to use moisture more economically, since they are heated by the sun less than the leaves would be heated, and, consequently, they evaporate much less water.

178. In the forest, the wind is broken by trees into separate streams and to a large extent loses its strength. Therefore, even on a cloudy day, the evaporation of moisture there is less intense than in the meadow, and the grass in the forest dries more slowly.

179. When harrowing, soil capillaries are destroyed and moisture evaporation is significantly reduced.

180. Evaporation of sweat from the body of an animal promotes heat exchange, but the sweat glands in a dog are located only on the pads of the "fingers", therefore, in order to increase the cooling of the body on a hot day, the dog opens its mouth wide and sticks out its tongue. Evaporation of saliva from the surface of the mouth and tongue lowers her body temperature.

186. The phenomenon of the transition of mechanical energy into the internal energy of the interaction of bodies (air - ship)

189. Plant juices are aqueous solutions of various salts that freeze at temperatures lower than 0 0 С.

190. With sharp changes in temperature due to unequal thermal expansion coefficients of dentin and enamel, large internal stresses arise in the tooth, which gradually destroy it.

191. The leaves of many plants contain oily substances, and therefore are not wetted by water.

192. They are not able to overcome the forces of surface tension.

193. Surface tension creates a kind of elastic film on the surface of water. The legs of water striders are not wetted by water and therefore do not penetrate into the depths. The surface film of water only slightly bends under the slight weight of the insect.

201. When birds become fluffy, the layer of air between the feathers increases and, due to poor thermal conductivity, delays the transfer of heat from the bird's body to the surrounding space.

211. All the mechanical energy of a bird when braking in the snow is converted into internal energy.

212. Exhaust gases do work by decreasing their internal energy and, consequently, by lowering the temperature.

213. The density of birch is greater than that of pine. Therefore, the mass of birch firewood with a volume of 1 cubic meter is greater than the mass of pine firewood of the same volume.

217. The juices contained in a tree, when frozen, increase in volume and at the same time crack the fibers of the plant with a crack.

224. ≈0.48 m/s.

230. Efficiency=(1- )∙100%=80%; 10 5 W

231. Efficiency \u003d 1-T 2 mR\(ρVμ) \u003d 0.5

234. ≈2.26 kg. In the process of work, when the car is slipping, the internal energy of the snow increases. Due to this energy, the snow heats up to the melting temperature and melts, so we get: A \u003d Q 1 + Q 2. since A \u003d Pt, and Q 1 \u003d cm (t-t 0) and Q \u003d mλ, the equation can be written as:

Pt=сm(t-t 0) + mλ or Pt=m(с (t-t 0) + λ)

From: m=
. Substituting the numerical values ​​we get: ≈2.26 kg

235. Yes, but as a result of the rapid melting of ice, the flood would be super-abundant.

247. At high altitude, the air is supersaturated with water vapor. The aircraft introduces condensation centers onto which steam condenses.

251. will not decrease.

256. Low humidity contributes to the evaporation of moisture and cooling of the skin and respiratory organs of a person.

285.3.36W; 6,

288. 198 light bulbs

285.3.36W; 6.72Wh

electricity and magnetism.

272. The most famous electric fish are electric eel, electric ray and electric catfish. These fish have special organs for the accumulation of electrical energy. Small tensions arising in ordinary muscle fibers are summarized here due to the successive inclusion of many individual elements, which are connected by nerves, like conductors, into long batteries. So, the electric eel, which lives in the waters of tropical America, has up to 8 thousand plates, separated from one another by a gelatinous substance. Each plate has a nerve coming from the spinal cord. From the point of view of physics, these devices represent a kind of system of high-capacity capacitors. The eel, by accumulating energy in its capacitors and discharging it at will through the body that touches it, produces electric shocks that are extremely sensitive to humans and deadly to small animals. In a large eel that does not discharge for a long time, the voltage at the moment of impact can reach 800 V. Usually it is somewhat less.

Among other electric fish, the torpedo stingray, which is found in the Atlantic, Indian and Pacific oceans, stands out. The dimensions of the torpedo reach two meters, and its electric organs are made up of several hundred plates. The torpedo is capable of delivering 150 discharges per second, 80V each, for 10-16 seconds. Electric organs of large dashboards develop voltage up to 220V.

A special type of electric organ in the electric catfish, giving discharges up to 360V. His electric organ is located in a thin layer under the skin throughout the body.

A characteristic feature of fish with electric organs is their low susceptibility to the action of an electric current. Some carry up to 220V.

273. An electric current passed through the wet film of the surface of the body and did not penetrate into the body, so the rat remained unharmed.

274. The current, passing through the human body, affects the central and peripheral nervous systems, causing disturbances in the functioning of the heart and breathing.

275. Of all the tissues that make up the body, the outer layers of the skin have the least conductivity, and the nerve fibers have the greatest, so the current in the body passes mostly along the nerve fibers and thereby affects the entire nervous system.

276. Ideal insulators do not exist, even porcelain, from which high-voltage insulators are made, changes its properties depending on the weather. The slightly dusty and moistened surface of the insulator serves as a current conductor. If we take into account that a high voltage current flows through the wires, then its leakage, even a small one, will be life-threatening.

277. Trees with roots penetrating into deep aquifers of the soil are better connected to the earth, and therefore, under the influence of electrified clouds, significant charges of electricity flowing from the earth accumulate on them, having a sign opposite to that of the charge of clouds.

278. In no case should you think that if you stand under a lightning rod during a thunderstorm, it will always protect you from lightning. If you stand even at a small distance from the lightning rod, then an induced charge is formed in your body at the moment of a lightning strike. Between it and the charge of the lightning rod, a discharge in the form of a spark can easily occur. All these considerations apply to tall, solitary trees. If you stand in the steppe at a distance of tens of meters from a lone tree, then you are better protected from lightning strikes than if there were no tree. If a person is near a tree, then it may happen that lightning in some cases chooses its way through the body of a person, since it is the same conductor as a tree.

279. Birds most often die in three cases when, sitting on a wire, they touch the pole with their wing, tail or beak, that is, they are connected to the ground.

280. The described phenomenon is called "the fires of St. Elmo." This is a very rare occurrence. On points, on fence posts, sometimes even on people's heads, a bluish light appears. This is a quiet discharge - the movement of electrons in air at atmospheric pressure and high voltage.

297. The body of a bird can be considered as a parallel connection to a section of a high-voltage circuit enclosed between the legs of a bird. Since the resistance of the bird is much greater than the resistance of this section, the current in the body of the bird is very small and harmless to it.

321. It has been established that a magnetic field is formed along the excited nerve approximately 0.0005 s before the transfer of excitation. Apparently, at the moment of irritation, the molecules that carry a charge somehow change their position in space, allowing a wave of excitation to pass through the nerve. It is this movement of molecules that is probably the cause of the magnetic field.

322. In the rivers of Africa, a fish equipped with a real radar was found. This is a water elephant. It turned out that the electric generator located in its tail part constantly emits low-frequency vibrations (up to 100 pulses per minute), which are captured by special organs of this fish located at the base of the fin. Therefore, it is not surprising that the water elephant, even burrowing headlong into the silt, feels the approach of a predator at a distance and manages to hide in time. The electric eel has the same locator.

323. Chemical

Optics.

342. The eye senses light with the help of light-sensitive cells: cones and rods. More sensitive are rods and less sensitive are cones. In low light, light is perceived by rods, not cones. But sticks do not cause color sensations, so all objects appear gray.

343. In the air, the outer cornea of ​​the eye collects light rays, creates an image on the retina, and the lens only slightly helps in this. Under water, however, the effect of the cornea is reduced to zero due to the fact that the refractive indices of water and the liquid inside our eye are almost the same, and the rays, without being refracted, pass directly through the cornea. Under water, we become, as it were, far-sighted.

344. The refractive index of the body of an insect is close to the refractive index of water, and the refractive index of the eye is different from the refractive index of water. Light would pass through transparent eyes without irritating the optic nerves. These organisms are visible in the air.

345. Such an original structure of the eyes is explained by the fact that both underwater organisms and air insects serve as food for the four-eyed. Swimming at the very surface of the water, the fish puts out the upper halves of the eyes and monitors what is being done above the water. The lower halves of the eyes monitor what is happening in the water.

346. The horizontal location of the pupil expands the angle of view in the horizontal plane. This is very important for animals that live on a flat open plain where predators need to be detected well in advance as soon as they appear on the horizon. In cats and foxes, the pupils are located vertically because these animals, looking for their prey, most often look up and down.

347. The retina of the eye is covered from the inside with a film consisting of many small cells - cones and rods. The cones allow you to see during the day, and the rods allow you to see at night. The peculiarities of the vision of chickens and owls are due to the fact that the retina in chickens consists only of cones, and in owls only of rods.

348. The eyes of man and some animals are adapted to the simultaneous examination of some object: the field of vision of the right eye only slightly differs from the field of vision of the left eye. Most animals look with each eye separately. The objects they see do not differ in relief, but their field of view is much wider.

349. The falcon's eye is arranged in such a way that the lens can become almost flat, as a result of which the image of distant objects falls on the retina.

350. Animals of white color radiate less heat into the surrounding space, which is especially important in the conditions of the north.

351. Dark color absorbs heat rays well. This allows insects to have a body temperature much higher than the ambient air temperature in sunny weather.

352. In the semi-darkness, under the dense branches of firs, only a white or pale pink color is clearly visible from afar, so insects pollinate only these flowers in search of nectar.

353. Many fish have a dark back and a silvery belly. From above, the dark back of the fish is not visible against the background of the dark bottom. From the water, the surface of the river seems to be mirror-like, and since the belly of the fish is silver, it is difficult for aquatic predators to notice it from below.

346. Iridescent shades of the wings of some insects are caused by interference phenomena. A similar phenomenon is observed in the feathers of many birds.

Nuclear physics.

354. Even in chemically pure uranium, the share of uranium - 235 is less than 1%. Therefore, the emitted neutrons are mainly absorbed by uranium-238 nuclei without subsequent nuclear fission.

356. m=m 1

357. m=m0 =26.9 kg

358. Safe, since the absorbed dose per year is 8.4 mGy.

359. Natural uranium contains only ≈0.7% of uranium-235 and the probability of a slow neutron meeting with a uranium-235 nucleus is low. The fission of uranium-238 nuclei is carried out by very fast neutrons, the number of which is very small.

Be great and make other people great.

(N. Tenzing)

HOW DO YOU SWEET?

When meeting with friends, acquaintances, we usually ask: “How are you?” But the ancient Egyptians believed that when meeting for a short time, there was no time and no need to do an analysis of one’s health. They asked specifically: "How do you sweat?" And everything became clear. If a person sweats well, then this is a sure sign of good health.

This most important hygienic procedure corresponds to one of the best traditions of the Russian people cultivated for centuries - to regularly take a steam bath. Humid hot air of the Russian bath warms up the whole body, opens the pores of the skin, expands the capillaries. All liquid systems of the body come into active movement: blood, lymph, tissue fluid. And if you add a fresh birch broom to the generous heat, then a person gets a feeling of unique intoxicating lightness - as if he had thrown off ten years.

Some researchers believe that if the capillaries thin, wriggle, narrow, then the speed of blood flow - the most important element of the exchange between blood and tissues - slows down. And with it, the supply of cells with oxygen and nutrients slows down. Only by deepening and cleaning the capillary beds, it is possible to achieve high cell viability. In addition, when the capillary bed becomes deep enough, it is easier for the body to introduce into it the "warships" of protection against infection - leukocytes. Therefore, the Russian bath is the basis for stimulating the body's natural defenses.

A lot has been written about the various types of baths and their effect on the human body. One of the most successful books on this issue is the repeatedly reprinted book by A. Galitsky "Generous Heat". It should be borne in mind that the habit of steaming in the bath develops the ability to sweat in a special way. Under the influence of systematic thermal training, the content of fatty substances in sweat increases due to the increased activity of the sebaceous glands. This leads to a decrease in the surface tension of sweat, as a result of which it is more evenly distributed over the entire surface of the skin, the total evaporation area increases, and hence heat transfer. Another feature of more perfect sweating is a decrease in the concentration of sodium chloride in the sweat, due to which the loss of salts by the body during profuse sweating is reduced.

As is known, the evaporation process proceeds with a large expenditure of energy: about 600 cal of heat is spent per 1 g of water to convert it into steam. It is no coincidence that in hot countries water is kept in porous clay vessels, from the surface of which the seeping moisture is slowly evaporating all the time. As a result, the water in the vessel remains constantly cool.

There is reason to believe that when the air temperature rises from 20 to 30 ° C, the metabolism of our body decreases, and this also contributes to cooling the body. But if the air temperature has exceeded 35 ° C, then the body, struggling with overheating, significantly enhances the process of sweating, which requires additional energy. Therefore, the metabolism rises again.

Man adapts to the heat better than is generally thought: in the southern countries he is able to endure temperatures much higher than what we in the temperate zone consider barely tolerable. In summer in Central Australia, temperatures of 46 and even 55 ° C are often observed in the shade. When crossing the Red Sea to the Persian Gulf, the temperature in the ship's rooms reaches 50 ° C and above.

The highest temperatures observed on our planet have not yet exceeded 57 ° C. This temperature is set in the so-called Death Valley in California. The heat in the Central Asian republics of the USSR - zones with the hottest climate - does not exceed 50 ° C.

Foreign scientists conducted special experiments to determine the highest temperature that the human body can withstand in dry air. An ordinary person withstands a temperature of 71 ° C for 1 hour, 82 ° C - 49 minutes, 93 ° C - 33 minutes, and 104 ° C - only 26 minutes.

However, seemingly improbable cases are also described in the literature. Back in 1764, the French scientist Tillet reported to the Paris Academy of Sciences that one woman was in an oven at a temperature of 132 ° C for 12 minutes.

In 1828, a case was described of a man staying in a furnace for 14 minutes, where the temperature reached 170 ° C. The English physicists Blagden and Chantry, as part of an autoexperiment, were in a bakery oven at a temperature of 160 °C. In Belgium, in 1958, a case was recorded of a person tolerating a 5-minute stay in a heat chamber at a temperature of 200 ° C. In the words of the physicist John Tyndall, you can boil eggs and fry a steak in the air of a room in which people remain harmless for a certain time.

In the United States, aviation medicine experts determined the time of exposure to thermal stress, limited by pain and applied in the form of thermal impulses, on subjects dressed in various clothes. The temperature of the walls of the thermal chamber increased starting from 20°C at a rate of 55°C per 1 min. Pain sensations arose when the skin temperature rose to 44 ° C, and at 45 ° C the pain became simply unbearable. It turned out that in the naked state a person can withstand such an increase in the temperature of the walls of the thermal chamber up to 210 ° C, and in heavy winter flight clothes - up to 270 ° C. Therefore, it is not at all surprising that the inhabitants of the desert, for example, the Turkmen, escape from the heat with the help of warm coats and fur hats. Due to this clothing, more stable thermoregulation conditions are maintained in hot climates.

What explains the super-endurance of a person to the effects of high temperatures? And the fact that a trained body struggles with heating primarily through profuse sweating; The evaporation of sweat absorbs a significant amount of heat from the air that is directly adjacent to the skin, and thus sufficiently lowers its temperature. The only conditions necessary for this are that the body should not come into direct contact with a source of heat and that the air be as dry as possible.

Currently, dry-air baths are becoming more widespread - saunas, in which the air temperature can rise to 100 ° C and above. And how will a person endure such a sauna, being, for example, at a biomedical station on the top of Elbrus? In our studies, which were carried out in a thermal pressure chamber, it was found that at the height of the top of Elbrus, a twenty-minute stay of a person at an air temperature of +100 ° C is even easier to bear than at the foot. And this interesting fact is explained by the fact that with an increase in the rarefaction of the atmosphere, heat transfer is simultaneously facilitated. In addition, a more pronounced oxygen deficiency at the height of the Elbrus summit can reduce the body's heat generation.

Anyone who has been to Central Asia has noticed how relatively easily tolerated there is 30- and even 40-degree heat. But in Moscow or Leningrad, even at lower air temperatures, people feel worse. And all because of the fact that the humidity in the central regions of our country is much higher than in most of Central Asia.

A low-calorie vegetarian diet helps to endure the heat. A good example of this is the Tubu people, who live in the very heart of the Sahara, however, they are distinguished by excellent health and great physical endurance. Scientists have come to the conclusion that the main mystery of the tuba is their diet, which consists of a thick herbal decoction, dates, boiled millet, palm oil, grated root sauce.

When a person stays in hot water, the possibility of heat transfer by evaporation of sweat is excluded. Therefore, the tolerance of high temperatures in the aquatic environment is much lower than in dry air. The "record" in this area probably belongs to one Turk, who, like Ivan Tsarevich, could plunge headlong into a cauldron of water at a temperature of +70 °C. Of course, to achieve such "records" a long and constant training is necessary.

In addition to bath attendants and workers in the so-called hot shops, cosmonauts can also encounter very high temperatures in various emergency situations, for example, when a spacecraft “abnormally” enters the dense layers of the atmosphere or the thermoregulation system fails. Therefore, the cosmonauts are tested in a special thermal chamber, called by Andrian Nikolaev the "devil's stove."

When selecting the first cosmonauts in the United States for flights under the Mercury program, they were required to have impeccable tolerance to thermal stress: a two-hour stay in a chamber with an air temperature of +50 °C.

And here is how O. Kudenko describes the tolerance of heat load by the first cosmonaut of the planet Yuri Gagarin in the book “The Orbit of Life” (1971): “At first, warm air is pleasant, but after ten minutes perspiration appears on the face. Yuri wipes sweat with a towel. But wet salt covers the face again and again. The temperature is rising. Heat is replaced by heat. The ears are the first to feel it. Hot dry air all around. He comes from everywhere. There is no escape from him. The mucous membrane of the nose and mouth dries. Every ten minutes, Yuri is given a thermometer through a narrow window. It must be put under the tongue with lightning speed - otherwise it will burst from the heat. Blood is pounding in the temples. And the training continues. “No, don't wait, doctors, Gagarin won't give the all-clear signal! It will hold on for as long as it takes. He has willpower!"

The gaze involuntarily glides over the thermometer. The column of mercury continues to crawl upwards barely noticeably. But here he froze at the number "70". Yuri looks at his watch: it seems like an eternity has passed since he was in the cell. Meanwhile, only a hundredth minute ends ...

Heavy dopey drowsiness gradually envelops consciousness. But the hand firmly holds the handrails of the chair, and half-closed eyes stare intently at the thermometer. He read somewhere that a person can withstand a temperature of 150-160 ° C with short-term heating. But there is a limit to everything! And it seems to Yuri that there is no limit to this test. He tries to relax. Drives away the thought of unbearable heat. He thinks about the North, about the cold sea, about the winter cold. He remembers the familiar granite fiords, waterfalls bubbling over the stones, dousing with cool transparent dust ... And it seems to him that it becomes easier to breathe.

Another look at the thermometer. The mercury is frozen. “So I won’t get married!” - Yuri smiles, and then another thought: “Great bathhouse! All the microbes must have died, but I’m fine, alive and well!” His consciousness woke up again, his brain started to work. "Adjusted!" - happily thinks Yuri. The body already seems to weigh nothing: everything has evaporated from it. Easy and hard at the same time. It is difficult to move, because the slightest movement causes torment; hot clothes touch the skin, and for some reason the skin is very sensitive ... Yuri does not know how much longer he needs to sit here, he is not very sure that this torture is necessary at all, this torture with heat ... But he, clenching his teeth, sits and silently looks at thermometer. It seems that mercury cannot master the next division in any way, crawl over it. So it is. stuck on the number "80". "And that's good." The heat eats the eyes. It has long been dry in the mouth, the tongue does not move, the skin on the face burns from the salt that has come out. The sweat is all gone - and the towel is no longer needed ...

The doctors stop the experiment. Gagarin comes out of the heat chamber. His face is burgundy red, and his eyes are shining. Wearily, he sits down in a chair and begins to fan himself with a towel. Pours and greedily drinks salted soda. Some of his comrades lost up to 4 kilograms of weight in a heat chamber. He lost 1380 grams."

Studies in a heat chamber conducted in the United States have shown that a person's body temperature during such a test can rise to 40.3 ° C, while the body is dehydrated by 10%. The body temperature of the dogs was brought even up to 42 °C. A further increase in the body temperature of animals (up to 42.8 ° C) was already fatal for them ...

However, in infectious diseases accompanied by fever, some people are able to tolerate even higher body temperature. For example, an American student from Brooklyn, Sophia Sapola, had a body temperature exceeding 43 ° C during brucellosis.

This is about heat. In the next chapter, we will travel to a qualitatively different world - the world of cold. Considering various interesting facts about the extraordinary resistance of man to cold, each of us will be able to at least mentally test our bodily and spiritual reserves in the cold. And some, perhaps, will remember their own unprogrammed freezing or voluntary contractions with the cold in the ice hole. He will remember and once again say to himself: “No, man is not weak!”

ALONE WITH THE COLD

From ancient times, a parable has come down to us about a pampered Roman, accustomed to a warm climate, who came to visit a half-naked and barefoot Scythian. "Why don't you freeze?" - asked the Roman, wrapped from head to toe in a warm toga and yet shivering from the cold. "Does your face get cold?" - asked the Scythian in turn. Having received a negative answer from the Roman, he said: "I am all like your face."

Already from the above example, it can be seen that resistance to cold largely depends on whether a person regularly engages in cold hardening. This is also confirmed by the results of observations by forensic experts who studied the causes and consequences of shipwrecks that occurred in the icy waters of the seas and oceans. Unhardened passengers, even in the presence of life-saving equipment, died from hypothermia in icy water in the first half hour. At the same time, cases were recorded when individual people struggled for life with the piercing cold of icy waters for several hours.

So, during the Great Patriotic War, Soviet sergeant Pyotr Golubev swam 20 km in icy water in 9 hours and successfully completed a combat mission.

In 1985, an English fisherman demonstrated an amazing ability to survive in icy water. All his comrades died of hypothermia 10 minutes after the shipwreck. He swam in the icy water for more than 5 hours, and when he reached the ground, he walked barefoot along the frozen lifeless shore for about 3 hours.

A person can swim in icy water even in very severe frost. At one of the winter swimming holidays in Moscow, the hero of the Soviet Union, Lieutenant-General G. E. Alpaidze, who hosted the parade of its participants, “walruses”, said: “I have been experiencing the healing power of cold water for 18 years now. That's how much I swim in the winter. During his service in the North, he did this even at an air temperature of -43 ° C. I am sure that swimming in frosty weather is the highest level of hardening of the body. One cannot but agree with Suvorov, who said that "ice water is good for the body and mind."

In 1986, Nedelya reported on Boris Iosifovich Soskin, a 95-year-old walrus from Evpatoria. Radiculitis pushed him into the hole at the age of 70. After all, properly selected doses of cold are able to mobilize the reserve capabilities of a person. And it is no coincidence that in Japan and Germany, for the treatment of certain forms of rheumatism, the "anti-sauna" invented by the Japanese professor T. Yamauchi is used. The procedure takes a little time: a few minutes in the "dressing room" at -26 ° C, and then exactly 3 minutes in the "bath" at -120 ° C. Patients have masks on their faces, thick gloves on their hands, but the skin in the area of ​​diseased joints is completely exposed. After one cold session, joint pain disappears for 3-4 hours, and after a three-month course of cold treatment for rheumatoid arthritis, there seems to be no trace left ...

More recently, it was believed that if a drowned person is not pulled out of the water within 5-6 minutes, he will inevitably die as a result of irreversible pathological changes in the neurons of the cerebral cortex associated with acute oxygen deficiency. However, in cold water this time can be much longer. So, for example, in the state of Michigan, a case was recorded when 18-year-old student Brian Cunningham fell through the ice of a frozen lake and was removed from there only after 38 minutes. He was brought back to life by artificial respiration with pure oxygen. Earlier, a similar case was registered in Norway. Five-year-old boy Vegard Slettemoen from the city of Lillestrom fell through the ice of the river. After 40 minutes, the lifeless body was pulled ashore, they began to do artificial respiration and heart massage. Soon there were signs of life. Two days later, consciousness returned to the boy, and he asked: “Where are my glasses?”

Such incidents with children are not such a rarity. In 1984, four-year-old Jimmy Tontlevitz fell through the ice of Lake Michigan. For 20 minutes of being in ice water, his body cooled to 27 °. However, after 1.5 hours of resuscitation, the boy was brought back to life. Three years later, seven-year-old Vita Bludnitsky from the Grodno region had to stay under the ice for half an hour. After a thirty-minute heart massage and artificial respiration, the first breath was recorded. Another case. In January 1987, a two-year-old boy and a four-month-old girl, having fallen into a Norwegian fiord to a depth of 10 m in a car, were also brought back to life after a quarter of an hour of being under water.

In April 1975, 60-year-old American biologist Warren Churchill was counting fish on a lake covered with floating ice. His boat capsized, and he was forced to stay in cold water at a temperature of +5 ° C for 1.5 hours. By the time the doctors arrived, Churchill was no longer breathing, he was all blue. His heart was barely audible, and the temperature of the internal organs dropped to 16 ° C. However, this man survived.

An important discovery was made in our country by Professor AS Konikova. In experiments on rabbits, she found that if the body of an animal is quickly cooled no later than 10 minutes after the onset of death, then after an hour it can be successfully revived. Probably, this is precisely what can explain the amazing cases of reviving people after a long stay in cold water.

In the literature, there are often sensational reports of human survival after a long stay under a block of ice or snow. It is hard to believe in this, but a person is still able to endure a short-term hypothermia.

A good example of this is the case that happened to the famous Soviet traveler G. L. Travin, who in 1928-1931. traveled alone on a bicycle along the borders of the Soviet Union (including the ice of the Arctic Ocean). In the early spring of 1930, he settled down for the night as usual, right on the ice, using ordinary snow instead of a sleeping bag. At night, a crack formed in the ice near his lodging for the night, and the snow that covered the brave traveler turned into an ice shell. Leaving part of the clothes frozen to him in the ice, G. L. Travin, with frozen hair and an “ice hump” on his back, reached the nearest Nenets tent. A few days later he continued his bicycle journey through the ice of the Arctic Ocean.

It has been repeatedly noted that a freezing person can fall into oblivion, during which it seems to him that he found himself in a very heated room, in a hot desert, etc. In a semi-conscious state, he can throw off his felt boots, outerwear and even underwear. There was a case when a criminal case of robbery and murder was initiated regarding a frozen person who was found naked. But the investigator found that the victim undressed himself.

But what an extraordinary story happened in Japan with the driver of the refrigerated car Masaru Saito. On a hot day, he decided to rest in the back of his refrigerator. In the same body were blocks of "dry ice", which are frozen carbon dioxide. The door of the van slammed shut, and the driver was left alone with the cold (-10 ° C) and the CO 2 concentration rapidly rising as a result of the evaporation of "dry ice". It was not possible to establish the exact time during which the driver was in these conditions. In the wreath case, when he was pulled out of the body, he was already frozen, nevertheless, after a few hours, the victim was revived at the nearest hospital.

It must be said that very high concentrations of carbon dioxide are necessary to obtain such an effect. We had to observe two volunteers who were at zero air temperature in the same swimming trunks for about an hour and all this time they breathed a gas mixture containing 8% oxygen and 16% carbon dioxide. One of them did not feel cold at the same time, did not shiver, and cooled down on average every 5 minutes by 0.1°. However, the other person continued to shiver from the cold all this time, thereby increasing the formation of heat in the body. As a result, his body temperature barely changed.

At the time of clinical death of a person from hypothermia, the temperature of his internal organs usually drops to 26–24 ° C. But there are known exceptions to this rule.

In February 1951, a 23-year-old black woman was brought to the hospital in the American city of Chicago, who, in very light clothes, lay for 11 hours in the snow with air temperature fluctuating from -18 to -26 ° C. The temperature of her internal organs at the time of admission to the hospital was 18 °C. Cooling a person to such a low temperature is very rarely decided even by surgeons during complex operations, because it is considered the limit below which irreversible changes in the cerebral cortex can occur.

First of all, doctors were surprised by the fact that with such a pronounced cooling of the body, the woman was still breathing, although rarely (3-5 breaths per 1 minute). Her pulse was also very rare (12-20 beats per minute), irregular (pauses between heartbeats reached 8 s). The victim managed to save her life. True, her frostbitten feet and fingers were amputated.

Somewhat later, a similar case was registered in our country. On a frosty March morning in 1960, a frozen man was brought to one of the hospitals in the Aktobe region, found by workers at a construction site on the outskirts of the village. During the first medical examination of the victim, the protocol recorded: “A numb body in icy clothes, without a headdress and shoes. The limbs are bent at the joints and it is not possible to straighten them. When tapped on the body, a dull sound, as from blows on wood. Body surface temperature below 0 °C. The eyes are wide open, the eyelids are covered with an ice edge, the pupils are dilated, cloudy, there is an ice crust on the sclera and iris. Signs of life - heartbeat and respiration - are not determined. The diagnosis was made: general freezing, clinical death.

It is difficult to say what motivated the doctor P.S. Abrahamyan, whether professional intuition, or professional unwillingness to come to terms with death, but he nevertheless placed the victim in a hot bath. When the body was freed from the ice cover, a special complex of resuscitation measures began. After 1.5 hours, weak breathing and a barely perceptible pulse appeared. By the evening of the same day the patient regained consciousness.

The questioning helped to establish that V. I. Kharin, born in 1931, lay in the snow without boots and headgear for 3-4 hours. The result of his freezing was bilateral lobar pneumonia and pleurisy, as well as frostbite of the fingers, which had to be amputated. In addition, for four years after freezing, V. I. Kharin retained functional disorders of the nervous system. Nevertheless, the "frozen" remained alive.

If Kharin had been brought in our time to the specialized city clinical hospital No. 81 in Moscow, then, probably, even without amputation of the fingers. Frozen people are saved there not by immersion in a hot bath, but by injecting drugs into the central vessels of the icy parts of the body that thin the blood and prevent its cells from sticking together. Warm streams slowly but surely make their way through the vessels in all directions. Cell after cell wakes up from a deadly sleep and immediately receive saving “sips” of oxygen and nutrients.

Let's take another interesting example. In 1987, in Mongolia, the child of M. Munkhzai lay for 12 hours in a field in 34-degree frost. His body was stiff. However, after half an hour of resuscitation, a barely distinguishable pulse appeared (2 beats per 1 minute). A day later he moved his hands, after two he woke up, and a week later he was discharged with the conclusion: "There are no pathological changes."

At the heart of such an amazing phenomenon lies the ability of the body to respond to cooling without triggering the mechanism of muscle trembling. The fact is that the inclusion of this mechanism, designed to maintain a constant body temperature under cooling conditions at any cost, leads to the "burning" of the main energy materials - fats and carbohydrates. Obviously, it is more beneficial for the body not to fight for a few degrees, but to slow down and synchronize the processes of life, to make a temporary retreat to the 30-degree mark - thus, strength is preserved in the subsequent struggle for life.

There are cases when people with a body temperature of 32–28 ° C were able to walk and talk. The preservation of consciousness in chilled people at a body temperature of 30–26 °C and meaningful speech even at 24 °C has been registered.

Is it possible to increase the body's resistance to cold? Yes, you can with the help of hardening. Hardening is necessary primarily to increase the resistance of the human body to factors that cause colds. After all, 40% of patients with temporary disability lose it precisely because of a cold. Colds, according to the calculations of the State Planning Committee of the USSR, cost the country more than all other diseases combined (up to 6 billion rubles a year!). And the fight against them must begin from early childhood.

Many parents believe that in urban conditions, colds in children are inevitable. But is it? More than twenty years of experience of a large family of teachers Nikitins showed that children can live without getting sick, provided they have the right physical education. Nikitin's baton was picked up by many families. Let's take a look at one of them - the Moscow family of Vladimir Nikolaevich and Elena Vasilievna Kozitsky. Elena Vasilievna - teacher, mother of 8 children. In the "Donikitin era" they all often suffered from colds, and one child even had bronchial asthma. But here in one, and then in another room of a three-room apartment, children's sports complexes appeared. Shorts became the usual clothes for children at home. Regular hardening was supplemented by dousing with cold water and walking barefoot, even in the snow. Each child was given the opportunity to sleep on the balcony at any time of the year. The food has also changed.

From food, the children were given everything they wanted, and gradually all of them, except for the oldest child, who was already 11 years old, lost their taste for meat food. Fresh vegetable and dairy products became the basis of children's nutrition.

As a result of this complex of health-improving measures, the morbidity of children has sharply decreased. Now only occasionally did one of them catch a mild cold, losing their appetite. Parents knew that loss of appetite during a cold is a natural defensive reaction of the body, and in such cases they did not force-feed their children. Appetite returned to them, as a rule, in one or two days, along with normal health.

The example of the Kozitsky family proved to be contagious. Neighbors and acquaintances began to bring their children to them “for re-education”. A kind of home health-improving kindergarten was formed. And this case is not isolated. In Moscow, there is a special parent club of the so-called non-standard parenting. More recently, the same club was created in Leningrad. The members of these clubs are parents who strive to master the art of being healthy and to teach this art to their children.

Interestingly, in the GDR there are children's winter swimming sections for boys and girls aged 10–12. Preliminary preparation for winter swimming in these sections is carried out for 7 weeks:

1st week - wiping with cool water, gymnastics with open windows or in the fresh air;

2nd week - cold shower;

3rd week - rubbing with snow;

4-6th weeks - entry into ice water up to the hips;

7th week - full immersion in ice water.

In our country, in the Moscow club "Healthy Family" and the Leningrad club "Nevsky Walruses" children are bathed in ice water even in infancy: they usually do no more than three dipping of the baby with his head under water for up to 4 seconds. Such "walrus" do not get sick. One of us (A. Yu. Katkov) was convinced of this by the example of his own sons.

A person can endure martial arts with a 50-degree frost, almost without resorting to warm clothes. It was this possibility that was demonstrated in 1983 by a group of climbers after climbing to the top of Elbrus. Wearing only swimming trunks, socks, mittens and masks, they spent half an hour in a thermal vacuum chamber - in a severe cold and rarefied atmosphere, corresponding to the height of the peak of Communism. The first 1–2 minutes of 50-degree frost was quite bearable. Then a strong shiver began to beat from the cold. There was a feeling that the body was covered with an ice shell. In half an hour it cooled almost a degree.

“Our fortifying frost is good for Russian health…” A. S. Pushkin once wrote. Today, the healing power of frost is recognized far beyond the borders of our country.

So, in 100 cities of the Soviet Union not so long ago there were about 50 thousand winter swimming enthusiasts, or “walruses”. Approximately the same number of "walruses" turned out to be in the German Democratic Republic.

Physiologist Yu. N. Chusov studied the reaction to the cold of the Leningrad “walruses” during their winter swimming in the Neva. The conducted research allowed us to conclude that winter swimming causes an increase in oxygen consumption by the body by 6 times. This increase is due to both involuntary muscle activity (cold muscle tone and trembling) and voluntary (warm-up before swimming, swimming). After winter bathing, in almost all cases there is visible shivering. The time of its occurrence and intensity depend on the duration of the winter swimming. Body temperature when staying in ice water begins to decrease after about 1 minute of bathing. For long bathing "walruses" it drops to 34 °C. Temperature recovery to the initial normal level usually occurs within 30 minutes after the end of combat with ice water.

A study of the heart rate in "walruses" showed that after 30 seconds of being in ice water without active muscle movements, it decreases on average from 71 to 60 beats per 1 min.

Under the influence of cold hardening in walruses, the heat production of the body increases. And not only increases, but also becomes more economical due to the predominance of free oxidation processes in the body. With free oxidation, the released energy is not stored in the form of reserves of adenosine triphosphoric acid (ATP), but is immediately converted into heat. A hardened organism allows itself even such a luxury as the expansion of peripheral vessels adjacent directly to the skin. This, of course, leads to an increase in heat loss, but additional heat loss is successfully compensated by increased heat generation in the body due to free oxidation. But due to the rush to the surface tissues of the body through the arterial vessels of oxygen-rich "hot" blood, the likelihood of frostbite decreases.

It is interesting that when the fingers are cooled, due to the narrowing of the capillaries, the thermal insulating properties of the skin can be increased by 6 times. But the capillaries of the skin of the head (with the exception of the front part) do not have the ability to narrow under the influence of cold. Therefore, at -4 °C, about half of the heat generated by the body at rest is lost through the cooled head if it is not covered. But immersing the head in ice water for more than 10 seconds in untrained people can cause a spasm of blood vessels that feed the brain.

All the more surprising is the incident that occurred in the winter of 1980 in the village of Novaya Tura (Tatar ASSR). In 29-degree frost, 11-year-old Vladimir Pavlov without hesitation dived into the wormwood of the lake. He did this in order to save a four-year-old boy who had gone under the ice. And he saved him, although for this he had to dive under the ice three times to a depth of 2 m.

Swimming in ice-cold water can also be used for medicinal purposes at the right dosage. For example, in the 1st city hospital of Kaluga, neuropathologist Ya. A. Petkov recommends winter bathing in the Oka to eliminate headaches and heart pains of neurotic origin, as well as attacks of bronchial asthma. Probably, the basis of this method of treatment is, as I. P. Pavlov said, “shaking the nerve cells”, that is, the positive effect of excessively cold water on the central nervous system.

On the southern coast of Crimea in the Yalta sanatorium. S. M. Kirov, for a number of years, sea bathing in winter has been used to treat patients with functional disorders of the central nervous system. Before plunging into the cold sea waves (the water temperature is usually not lower than 6 ° C), patients undergo a special hardening complex during the first week: air baths in the ward, night sleep on the verandas, daily washing of feet at night with cold water, walking, morning exercises in the fresh air, close tourism. Then they gradually begin to take sea baths lasting up to 3-4 minutes. Thus, neurasthenia and stage I hypertension are well cured.

Hardening of the body has no absolute contraindications. When used correctly, it can help the body "get out" of very serious ailments. A good example is the personal experience of Yuri Vlasov. Here is how he writes about this in his book “A Confluence of Difficult Circumstances”: “The first walks ... eight to twelve minutes of trampling near the entrance. There was not enough strength for more. I got wet and started to get sick. These first weeks I was accompanied by my wife and daughter. They carried spare things with them in case I was chilled or engulfed in the wind. Yes, yes, I was pathetic and ridiculous. I was like that, but not my determination...

I stubbornly stomped along the winter paths and repeated spells against colds. Gradually I pulled myself into a rather fast pace without breathlessness or sweat. This gave me confidence, and since February I have given up the coat. Since that time, I have only worn jackets, and every year in lighter ones…

I have done away with, so to speak, the power of the plaid and woolen shirt. Let the night fevers torment me - I will get up and change the sheets, but just do not pamper myself with a rug! Because of the microclimate under the woolen shirt, I found myself susceptible to any cooling. If before there was a need for such underwear, now I will outlive it. From clothes there is nothing more pampered and therefore dangerous. I forever abandoned sweaters with blind collars on a good part of the neck and scarves. Here in the city and our climate there are no conditions that would justify such clothing. Softness makes us susceptible to colds. I generally revised and thoroughly facilitated the wardrobe. Turning unnecessarily to excessively warm clothes, we train our defenses, make ourselves vulnerable to colds, and, consequently, more serious illnesses.

The later years of Yuri Vlasov's life are also convincing of the fidelity of these words: today he is practically healthy and creatively active.

It has now been established that, when used correctly under medical supervision, winter swimming can be a good helper in normalizing the following health conditions:

cardiovascular diseases without circulatory disorders - stage I hypertension, atherosclerotic cardiosclerosis and myocardial dystrophy without compensation disorders, arterial hypotension without severe weakness, neurocirculatory dystonia;

Lung diseases - inactive forms of tuberculosis in the phase of compaction and stable compensation, focal pneumosclerosis in the remission phase;

Diseases of the central nervous system - moderately expressed forms of neurasthenia;

Diseases of the peripheral nervous system - radiculitis, plexitis (without violation of compensation), with the exception of the period of exacerbation;

Diseases of the gastrointestinal tract: chronic gastritis, enteritis and colitis in a satisfactory general condition and the absence of pronounced spastic phenomena;

Some metabolic disorders.

In recent years, speed swimming competitions in ice water have become increasingly popular. In our country, such competitions are held in two age groups at distances of 25 and 50 m. For example, 37-year-old Muscovite Evgeny Oreshkin became the winner of one of the recent competitions of this type, who swam a 25-meter distance in 12.2 s in icy water. In Czechoslovakia winter swimming competitions are held at distances of 100, 250 and 500 m.

In addition to winter swimming, there is such a harsh method of hardening as running in shorts in frosty weather. The Kyiv engineer Mikhail Ivanovich Olievsky, whom we know, ran a distance of 20 km in just such a form in a 20-degree frost. In 1987, one of us (A.Yu. Katkov) joined Olievsky in such a race at a frost of 26 ° for half an hour. Fortunately, there were no frostbite due to regular hardening by other methods (swimming in an ice hole, light clothing in winter).

"Walruses", of course, are hardened people. But their resistance to cold is far from the limit of human capabilities. The aborigines of the central part of Australia and Tierra del Fuego (South America), as well as the Bushmen of the Kalahari Desert (South Africa) have even greater immunity to cold.

The high resistance to cold of the indigenous inhabitants of Tierra del Fuego was observed by Charles Darwin during his journey on the Beagle ship. He was surprised that completely naked women and children did not pay any attention to the thickly falling snow that melted on their bodies.

In 1958–1959 American physiologists studied the resistance to cold of the natives of the central part of Australia. It turned out that they sleep quite calmly at an air temperature of 5-0 ° C naked on the bare ground between fires, sleep without the slightest sign of trembling and increased gas exchange. At the same time, the body temperature of the Australians remains normal, but the skin temperature drops to 15 ° C on the trunk, and even up to 10 ° C on the limbs. With such a pronounced decrease in skin temperature, ordinary people would experience almost unbearable pain, and Australians sleep peacefully and feel neither pain nor cold.

How can one explain that acclimatization to the cold among the listed nationalities proceeds in such a peculiar way?

It seems that the whole point here is forced malnutrition and intermittent fasting. The body of a European responds to cooling by increasing heat production by increasing the level of metabolism and, accordingly, increasing the oxygen consumption of the body. Such a way of adaptation to cold is possible only, firstly, with short-term cooling, and secondly, with normal nutrition.

The peoples we are talking about are forced to stay in cold conditions without clothes for a long time and inevitably experience an almost constant lack of food. In such a situation, there is practically only one way to adapt to cold - limiting the heat transfer of the body due to the narrowing of peripheral vessels and, accordingly, lowering the skin temperature. At the same time, the Australians and many other natives in the process of evolution developed an increased resistance of the tissues of the surface of the body to oxygen starvation, which occurs due to the narrowing of the blood vessels that feed them.

In favor of this hypothesis is the fact of increased resistance to cold after many days of dosed starvation. This feature is noted by many “hungerers”. And it is explained simply: during fasting, both heat production and heat transfer of the body decrease. After fasting, heat production increases as a result of an increase in the intensity of oxidative processes in the body, and heat transfer can remain the same: after all, the tissues of the body surface, being less important for the body, get used to a lack of oxygen during prolonged fasting and as a result become more resistant to cold.

In our country, an interesting system of cold hardening was promoted by P. K. Ivanov. He was engaged in hardening for more than 50 years (starting it after 30) and achieved amazing results. In any frost, he walked barefoot in the snow in only shorts, and not for minutes, but for hours, and did not feel any cold. P.K. Ivanov combined cold hardening with dosed starvation and autosuggestion of insensitivity to cold. He lived for about 90 years, and even the last years were not overshadowed by ill health.

We know that the young geologist V. G. Trifonov resorts to the same methods of increasing the body's resistance to cold. In Kamchatka, he was shocked by the news of the death from freezing of two of his comrades - practically healthy men. They could not stand the combat with the cold, although the deer accompanying them remained alive and safely reached the dwelling. V. G. Trifonov performed a number of cold experiments on himself. The results allowed him to draw the same conclusion that the brave "Robinsons" of the Atlantic had come to before him - the Frenchman A. Bombard and the German X. Lindeman: most often a person dies not from the cold, but from fear of it.

There is a report in the literature about the American Bullison who lived at the beginning of our century, who for 30 years ate exclusively raw plant foods, periodically starved for 7 weeks and walked in one “bathing raincoat” all year round in any weather.

On March 26, 1985, the Trud newspaper reported on 62-year-old A. Maslennikov, who spent 1.5 hours in the snow barefoot, without clothes and without a hat. Thanks to 35 years of experience in hardening, including winter swimming, this man did not even catch a cold.

Another example of the heroic combat of man with the cold. In February 1977, Komsomolskaya Pravda wrote about the extraordinary willpower of the young Air Force pilot Yuri Kozlovsky. An emergency situation arose in flight during the testing of the aircraft. He catapulted over the Siberian taiga from a dying plane. When landing on sharp stones, he received open fractures of both legs. The frost was 25–30 ° C, but the ground was bare, without a snowflake. Overcoming terrible pain, cold, thirst, hunger and fatigue, the pilot crawled for three and a half days until he was picked up by a helicopter. At the time of delivery to the hospital, the temperature of his internal organs was 33.2 ° C, he lost 2.5 liters of blood. The legs were frostbitten.

And yet, Yuri Kozlovsky survived. He survived because he had a goal and a duty: to tell about the plane that he tested, so that the accident would not happen again with those who should fly after him.

The case with Yuri Kozlovsky involuntarily brings us back to the years of the Great Patriotic War, when Alexei Maresyev, who later became a Hero of the Soviet Union, found himself in a similar situation. Yuri also had both legs amputated, and he was operated on twice due to severe gangrene. In the hospital, he developed a perforated duodenal ulcer, kidney failure set in, and his hands were inactive. The doctors saved his life. And he disposed of it with dignity: he lives full-blooded and actively. In particular, having shown extraordinary willpower, he learned to walk on prostheses the way he walked before misfortune on his own legs.

Doctor L.I. Krasov lives in Moscow. This man received a severe injury - a fracture of the spine with damage to the spinal cord in the lumbar region. As a result, atrophy of the gluteal muscles, paralysis of both legs. His surgeon friends treated him as best they could, but they did not hope that he would survive. And he “in spite of all deaths” restored the damaged spinal cord. The main role, he believes, was played by the combination of cold hardening with dosed starvation. Of course, all this would hardly have helped if this man had not had extraordinary willpower.

What is willpower? In fact, this is not always conscious, but very strong self-hypnosis.

Self-hypnosis also plays an important role in the cold hardening of one of the nationalities living in the mountainous regions of Nepal and Tibet. In 1963, a case of extreme resistance to cold was described by a 35-year-old mountaineer named Man Bahadur, who spent 4 days on a high-mountain glacier (5–5.3 thousand m) at an air temperature of minus 13–15 ° C barefoot, in a bad clothes, no food. Almost no significant impairments were found in him. Studies have shown that with the help of auto-suggestion, he could increase his energy metabolism in the cold by 33–50% through “non-contractile” thermogenesis, that is, without any manifestations of “cold tone” and muscle tremors. This ability saved him from hypothermia and frostbite.

But perhaps the most surprising is the observation of the famous Tibetan researcher Alexandra Da-vid-Nel. In her book "Magicians and Mystics of Tibet", she described the competition, which is held at the holes cut in the ice of an alpine lake, bare-chested yogis-respas. Frost is below 30°, but steam is pouring from respawns. And no wonder - they compete, how many sheets pulled out of the icy water, each will dry on his own back. To do this, they cause a state in their body when almost all the energy of vital activity is spent on generating heat. Respawns have certain criteria for assessing the degree of control of the thermal energy of their body. The student sits in the “lotus” position in the snow, slows down his breathing (as a result of the accumulation of carbon dioxide in the blood, the superficial blood vessels expand and the body’s heat transfer increases) and imagines that a flame is flaring up along his spine. At this time, the amount of snow that has melted under the seated person and the radius of melting around him are determined.

How can one explain such a physiological phenomenon, which seems downright incredible? The answer to this question is given by the results of the research of Alma-Ata scientist A.S.Romen. In his experiments, volunteers voluntarily increased their body temperature by 1–1.5 °C in just 1.5 minutes. And they achieved this again with the help of active self-hypnosis, imagining themselves somewhere in the steam room on the topmost shelf. Approximately the same technique is resorted to by yogis-respians, bringing the ability of an arbitrary increase in body temperature to amazing perfection.

Cold can promote longevity. It is no coincidence that the third place in the percentage of centenarians in the USSR (after Dagestan and Abkhazia) is occupied by the center of longevity in Siberia - the Oymyakonsky region of Yakutia, where frosts sometimes reach 60-70 ° C. Residents of another center of longevity - the Hunza Valley in Pakistan bathe in icy water even in winter at 15-degree frost. They are very frost-resistant and only heat their stoves in order to cook food. The rejuvenating effect of cold against the background of rational nutrition is reflected there primarily on women. At the age of 40, they are considered quite young, almost like our girls, at 50–60 years old they retain their slim and graceful figure, at 65 they can give birth to children.

Some nationalities have traditions to accustom the body to the cold from infancy. “The Yakuts,” wrote Russian academician I.R. Tarkhanov at the end of the last century in his book “On the Hardening of the Human Body,” “rub their newborns with snow, and the Ostyaks, like the Tungus, immerse babies in the snow, douse them with ice water and then wrap them in deer skins."

Of course, a modern city dweller should not resort to such risky methods of hardening children. But many people like such a simple and effective way of hardening as walking barefoot.

To begin with, this technique was the only way of walking on the earth of our ancestors. Even in the last century, children from Russian villages had one pair of boots per family, thus they had to harden their feet from early spring to late autumn.

Walking barefoot as a method of local hardening was one of the first to be proposed at the end of the 19th century. German scientist Sebastian Kneipp. He put forward hygienic slogans that were bold for that time: “The best shoes are the absence of shoes”, “Every barefoot step is an extra minute of life”, etc. Kneipp’s views are shared by many doctors in our time. For example, in some sanatoriums of the GDR, Germany, Austria, Finland, walking barefoot along the so-called contrast paths is widely used, the various sections of which are heated in different ways - from cold to hot.

It must be said that the foot is a special part of our body; there is a rich field of nerve endings-receptors here. According to the ancient Greek legend, it was through the feet that Antaeus received an influx of new forces from mother earth to fight Hercules. And there is probably some truth in this. After all, the rubber sole isolates us from the negatively charged earth, and the positively charged atmosphere steals some of the negative ions from a person. When walking barefoot, we, like Antaeus, receive the negative ions that we lack, and with them electrical energy. However, this assumption needs experimental verification.

Academician I. R. Tarkhanov believed that we “by artificial pampering of the legs have brought matters to the point that the parts that are naturally the least sensitive to temperature fluctuations turn out to be the most sensitive to colds. This feature is so universally recognized that polar explorers, when recruiting people, are guided, among other things, by the endurance of their soles to cold, and for this purpose they are forced to put their bare soles on the ice in order to see how long they can endure it.

In the United States, a similar technique was used in the selection of astronauts for the Mercury program. To test willpower and endurance, the astronaut candidate was asked to keep both feet in ice water for 7 minutes.

An interesting annual plan of measures for local hardening of the legs was recently developed by Voronezh specialists V. V. Krylov, Z. E. Krylova and V. E. Aparin. It begins in April by walking around the room barefoot. The daily duration of such a walk by the end of May should be 2 hours. At the end of May, you should also start walking or running barefoot on the ground and grass, increasing the daily duration of this procedure to 1 hour during the summer season. In autumn, along with the continuation of one hour of daily walking barefoot on the ground, it is useful do contrasting cold-hot foot baths. Finally, as soon as the first snow falls, one must begin to walk on it, gradually increasing the duration to 10 minutes. The authors of this complex claim that anyone who has mastered it is insured against colds. This is explained by a direct reflex connection between the state of the upper respiratory tract and the degree of cooling of the feet, which is especially pronounced in the winter-spring period.

In 1919, the Komsomol members of Petrograd, at the call of the hygienist Professor V.V. Gorinevsky, who argued that walking barefoot was healthier in the rear, donated their shoes to the Red Army and really walked barefoot all summer.

Interesting results were obtained during the examination of the health group of the Voronezh central stadium "Trud", where in the second year of hardening, barefoot running on ice and snow was practiced for 15 minutes, regardless of the weather. When a leg was immersed in ice water, the veterans of the group experienced an increase in skin temperature on the other leg by 1–2°, and the temperature was maintained at this level for the entire 5 min of cooling. In beginners, the skin temperature on the control leg, after a short-term increase of half a degree, dropped sharply below the initial level.

What perfection and endurance can be achieved with local cold hardening of the legs is evidenced by observations during one of the last American-New Zealand expeditions in the Himalayas. Some of the Sherpa guides made a many-kilometer journey along rocky mountain paths, through the zone of eternal snow ... barefoot. And this is in 20-degree frost!

And with mountain tourism, there are already many difficulties. Although, of course, not only difficulties. About the mountain climate, its importance for health promotion and,

Of course, we will talk about the reserves of the human body in single combat with hard-to-reach snow-white giants in the next chapter.

DRAG YOUR FRIEND TO THE MOUNTAINS…

During the celebration of the 60th anniversary of Max Planck in May 1918, A. Einstein, who delivered a speech, characterized the inner motives that lead people to the temple of science. Some seek in science the satisfaction of their ambition, others seek immediate practical results. But there are people who came to science or art in an effort to escape from everyday life. This motive, according to Einstein, can be compared with a passionate longing, irresistibly pulling a city dweller from his usual noisy and stupid environment into the peaceful regions of high mountains.

In the science fiction novel “Out of the Earth”, K. E. Tsiolkovsky spoke about a group of scientists of different nationalities who, preparing for a space flight, settled not just anywhere, but in the spurs of the Himalayas: “The proximity of city noise and people would irritate their wounds. The grandeur of the surrounding mountainous area, the ever-shining snow-white mountain giants, the ideally clean and transparent air, the abundance of the sun, on the contrary, calmed and strengthened them.

The desire of people to settle in mountainous areas can be traced from ancient times. In the Peruvian Andes, at relatively high altitudes, the ruins of villages were found, the age of which is determined at 10,000 years. In Tibet, at an altitude of 5000 m, there are abandoned mines (Tog-Jalung), in which gold was mined in the past.

In Peru, there are settlements located above 5000 m above sea level, and the Lima - Oroya railway crosses the mountain range at an altitude of 4800 m.

The highest mountain settlement is located in the Chilean Andes at an altitude of more than 5300 m, the mining village of Aukankilcha. Its inhabitants are miners. To get into the mine, they have to climb daily to a height of 5800 m.

It is interesting that back in the 30s. an alpine hut was built on the saddle of Elbrus (height 5300 m), where extensive research work was carried out for several years. In 1966, on the initiative of Academician N. N. Sirotinin, a medical-biological laboratory was installed by helicopter on the eastern peak of Elbrus (height 5621 m). True, these structures, unfortunately, could not stand the combat with the harsh winter Elbrus winds. Later, the staff of N. N. Sirotinin built a foam house on the southern slope of Elbrus in the area of ​​​​Pastukhov Stones, located at an altitude of 4700 m. But after a few years, he was completely dominated by ice. In the summer of 1974, during the Elbrus expedition, in which the authors of these lines took part, the house was freed from ice and repaired. In it, we conducted interesting studies on the effect of hypoventilatory training in high altitude conditions.

Since we are talking about the Pastukhov Stones, it is not superfluous to tell about their history, which clearly demonstrates the reserves of the human body in overcoming mountain sickness. On July 31, 1890, military topographer Andrey Vasilyevich Pastukhov went out with the Cossacks to the eastern peak of Elbrus. Above the very stones that now bear his name, Pastukhov was prevented by severe attacks of mountain sickness (general weakness, inability to move independently, nausea). Four times the Cossacks on cloaks carried him unconscious to these stones, however, having come to his senses and taking a break, Pastukhov again went to storm the heights! And again an attack of mountain sickness knocked him down, and again the Cossacks dragged him down ... Finally, on the sixth day of the assault, Pastukhov got to the eastern peak of Elbrus and worked there for 3.5 hours, making a topographic survey.

Speaking about the adaptation of the human body to a high-mountain climate, one cannot fail to pay tribute to the enormous 50-year work in this area done by N. N. Sirotinin. We have the right to consider him the "father" of Soviet alpine physiology and medicine. He was the first to put forward, experimentally substantiate and develop the principle of the so-called stepwise acclimatization, i.e. gradual adaptation to the mountain climate at ever-increasing altitudes, he proposed acid prevention of mountain sickness, which occurs due to a lack of oxygen and carbon dioxide is washed out of the body during shortness of breath . N. N. Sirotinin developed methods for treating bronchial asthma, anemia, and some mental illnesses in the mountain climate. The logic of N. N. Sirotinin’s research on high-altitude adaptation led to the formulation and solution of new problems: to use the body’s compensatory-adaptive reactions developed during training to overcome oxygen starvation to increase its resistance to the action of various extreme factors.

Studies by N. A. Agadzhanyan and M. M. Mirrakhimov showed that after three to four weeks of high-mountain adaptation at altitudes of 3000–4000 m, the body’s resistance to acute oxygen starvation (in a pressure chamber at an “altitude” of 7500 m), accelerations (when rotating at centrifuge), improve physical performance and tolerance to high temperatures.

And in our latest studies, it was found that with special training in a pressure chamber at an “altitude” of 7500 m, a person can stay at this “altitude” for as long on the third day as after a much longer stay in high altitude conditions.

What explains the expansion of the reserve possibilities of adaptation of the human body to the listed extreme factors with the help of the mountain climate? First of all, the fact that in the mountains, due to the significantly lower barometric pressure compared to sea level, the so-called partial pressure of oxygen in the atmospheric air also decreases. This is despite the fact that the percentage of oxygen in the atmosphere remains constant. Both at sea level and at the top of Everest, the air contains 20.9% oxygen. The decrease in the partial pressure of oxygen in the inhaled air that occurs in the mountains leads to oxygen starvation of the body, but at altitudes of 2000-4000 m it is quite moderate, and as a rule, a healthy person does not get mountain sickness if the principle of stepwise mountain adaptation is observed. At the same time, acute oxygen starvation underlies such tests as “lifting” in a pressure chamber and spinning in a centrifuge. It occurs during very hard physical work and overheating of the body. That is why mountain adaptation helps to improve the tolerance of all these extreme factors and is widely used in the training system of athletes, pilots and astronauts.

The inhabitants of the mountains have the greatest resistance to oxygen starvation. For example, Indians, natives of Moroccocha (altitude 5000 m), can be in a pressure chamber at "heights" 11500 - 12000 m for 1.5 minutes, while maintaining consciousness. If a healthy, but untrained person is lifted to such “heights” with an oxygen mask, and then removed, he will lose consciousness in the first half a minute. This will happen because with such a large rarefaction of the atmosphere, the oxygen tension in the arterial blood will be less than in the venous. A paradox will arise: despite increased breathing, oxygen, instead of entering the body, on the contrary, will begin to leave it. That is why pilots in the event of a sudden depressurization of the aircraft cabin at high altitudes are first of all recommended to take one deep breath and hold the air. Thus, they will win precious seconds, during which they will have time to put on and tightly fit a rescue oxygen mask to their face. But it is no longer easy to breathe pure oxygen at an altitude of 12,000 m, you have to supply it to the body under high pressure.

And in such conditions, the Indians from the village of Morokocha demonstrate miracles of super-resistance to oxygen starvation. What are the mechanisms of this superstability? Apparently, the natives of the mountains develop a special, so-called tissue, type of adaptation to hypoxia. Its essence lies in the fact that the tissues of the body, including the nerve cells of the cerebral cortex that are most sensitive to a lack of oxygen, reduce their need for it, switching partly to an oxygen-free (anaerobic) way of obtaining energy.

Alpinists also have great resistance to high-mountain hypoxia. As life shows, if you wish, you can remain a climber even after passing 100 years. In 1968, at the age of 116, the oldest climber of our country, Ts. A. Zalikhanov, died, whose whole life was spent at the foot of Elbrus. Before the revolution, he climbed the top of Elbrus together with S. M. Kirov, and T. A. Zalikhanov dedicated his last ascent to one of the peaks of this snow-white giant to his own 110th birthday.

In the spring of 1985, American Richard Bass broke the record for the age limit at which a person is able to conquer the highest peak in the world. He climbed to the top of Everest at the age of 56!

The history of mountaineering has its own milestones and events that mark the beginning or end of such and such a stage or period of its development. And if 1786, when the highest peak of the Alps-Mont-Blanc (4807 m) was climbed, is considered the year of the birth of world mountaineering, then the 20th century became the "golden age" of high-altitude mountaineering. Its beginning was the conquest of Trisul peak in the Himalayas (7123 m) by English climbers. In the following decades, several more seven-thousanders were conquered. Attempts to storm peaks over 8000 m did not bring success for a long time, although the “high-altitude Rubicon” (8000 m) was crossed in 1922. A new qualitative leap occurred in 1950, when French climbers mastered the first eight-thousander - Annapurna (8078 m).

This expedition to Annapurna is called "climbing on one will." In a hurry to reach the cherished peak before the onset of the monsoon, the climbers went on the assault without restoring strength at lower altitudes, without the necessary energy reserves. The descent from the summit was extremely difficult, but the courageous climbers emerged victorious from the fight with the mountains. Here is how the leader of this expedition, Maurice Herzog, describes one of the tragic moments of the descent from Annapurna after a cold night and falling into a snow avalanche: “A difficult test! My feet, hard as wood, scratch the ice wall. Numb hands cannot hold a thin rope. I try to wrap it around the brushes, but they are swollen, the skin is cracked in several places. Huge patches of skin detach and stick to the rope. The meat is exposed...

Every centimeter causes severe pain, but I firmly decided not to reckon with this. The sight of my hands makes me sick. The naked meat is bright red, the rope is covered in blood. I try not to completely tear off the shreds of skin: previous accidents have taught me that these tatters should be carefully preserved, as in this case the wound heals faster ... My hands are in a terrible state. I feel like all the meat has been torn off. Finally, the leg gropes for some kind of obstacle - this is a crevice. Still got it!"

Interestingly, if the North Pole was first reached on a dog sled by the American Robert Peary in 1909, and the South Pole by the Norwegian Roald Amundsen two years later, then a person stepped on the third, "high-altitude" pole of the planet only in 1953. Since that time following the New Zealand climber Edmund Killary and his partner Sherpa Norgay. With Tenzing, more than a hundred climbers managed to defeat the "Lord of the Sky", as the Nepalese call Everest. Soviet climbers reached its summit in 1982 along a route that was previously considered insurmountable.

Muscovite Eduard Myslovsky was in the first bunch, which went to the cherished goal by the most difficult route and hoisted the flag of our Motherland on the top of Everest. His climbing experience is an example not only of perseverance and courage, but also of subordinating to his will the capabilities of his own body. Along with glaciers, cracks, and rocks, the path to the top of Myslovsky was also blocked by various restrictions from medical commissions. And yet, the will hardened in the mountains helped to overcome barriers, to mobilize the body's reserves.

Eduard demonstrated these reserves to us a year before his triumphant Himalayan ascent, during an examination in a pressure chamber, where the main factor of the mountain climate, oxygen starvation, was simulated. The first examination revealed that he had an average tolerance for oxygen deficiency for a climber. His “altitude ceiling” (the limiting rarefaction of air in the pressure chamber, at which he could no longer correctly add single-digit numbers due to oxygen starvation of the brain) corresponded to staying at an altitude of 9 thousand meters for only 48 s. But after a short winter training camp in the Tien Shan mountains, he managed to overcome a 10-minute mark in the pressure chamber at the same “altitude”, and then (and also without an oxygen mask) spent almost 9 minutes on a 10-kilometer “top”.

Myslovsky's teammate Vladimir Balyberdin reached the 10-kilometer mark in the pressure chamber even before the training camp in the mountains. The record is held by the participants in the storming of Alma-Ata residents Yu. Golodov, V. Khrushchaty and S. Chepchev, who tolerated this “height” well without an oxygen mask for more than 10 minutes. It's understandable: they live near the Northern Tien Shan and can rest every week at an altitude of up to 3–4 km. Getting used to the mountain climate increases resistance to oxygen starvation.

And yet, the possibilities of a person at the current level of medical science are not unlimited. A good example is the observation of Yu. Golodov, a participant in the assault. He felt good with a 10-minute stay at an "altitude" of 10 km. They began to rarefy the air in the pressure chamber even more, and after 50 seconds the climber reached the 11-kilometer mark. And after another 10 seconds, I had to give him an oxygen mask ... The course of this examination was filmed and the film “Himalayan Gatherings” was turned on. Academician O. G. Gazenko supervised the research, who himself has repeatedly been in the mountains and knows many subtleties of high-altitude physiology.

During the preparation for the storming of Everest in Moscow, a member of the climbers' team proposed another functional test: rapid rarefaction of air in a pressure chamber at rest and in combination with physical work on a bicycle ergometer. And again, E. Myslovsky demonstrated the high reserve capabilities of his body. Before the training camp in the mountains, his results were very modest: at rest, the “high-altitude ceiling” was 8600, and during physical exertion - 7600 m. But after the training camp, these figures increased to 10500 and 8600 m, respectively. after returning from Everest, another participant in the ascent is Valery Khomutov. With a rapid rarefaction of the atmosphere in the pressure chamber, he managed to "rise" up to 11,000 m at rest and up to 9,600 m while working on a bicycle ergometer.

Climbing is associated not only with great physical, but also with neuropsychic stress. Therefore, the candidates for the storming of Everest were tested for the ability to control their psyche, primarily with the help of muscle relaxation. For most, it turned out to be quite good. Yes, in high-altitude mountaineering it is impossible without it. After all, muscle relaxation reduces oxygen consumption. Extensive experience in high-altitude ascents has developed in many climbers a very important ability to relax as much as possible muscle groups that are currently not loaded.

Four Soviet climbers for the first time in the world climbed the summit of Everest at night. The difficulty of such an ascent is not only in poor visibility. At this time, physical and mental performance decreases. Once again, it was proved that a trained strong-willed person is able to perfectly control his body, its biorhythms, and demonstrate great endurance at any time of the day.

The medical specialists who took part in the preparation of the Himalayan team made their contribution to the success of the national mountaineering. Conquering the summit of Everest along a previously considered inaccessible route, and even at night, is not only a sporting feat. It is also an important contribution to the science of expanding the reserve capacity of the human body.

In the spring of 1934, the former captain of the British Army, Wilson, set out to land on an airplane on the slopes of Everest as high as possible and from there walk to its summit. When he was refused this, he penetrated into Tibet, dressed in the clothes of a local resident and, hiring three porters and a horse, hastily moved to the mountain. Seeing the folly of such an undertaking, the Tibetans refused to accompany him on his ascent. Wilson tried in vain to reach the North Col (7007 m) alone and eventually died from cold and exhaustion. His body and diaries were found the following year in a torn tent at an altitude of 6400 m.

In 1947, a similar attempt was made by the Canadian Denman, who was accompanied by two Sherpas, including the future Everest conqueror Tenzing. However, he was unable to reach the North Col. In the spring of 1951, the Dane Becker-Larsen, accompanied by four Sherpas, passed the Nangpala pass. (5500 m) from Nepal to Tibet and made a lightning attack on Everest from the north, but was also stopped below the North Col. In 1953, the Austrian climber Herman Buhl was the first to single-handedly conquer the most treacherous eight-thousander Nanga-Par-bat - the "mountain of horrors". He began his assault early in the morning from the camp at an altitude of 6789 m with a partner. However, the latter lagged behind and turned back, barely overcoming a height of 7500 m. Buhl, left without food supplies, nevertheless reached the summit in the evening, and on the way back he had to spend the night without a tent at an altitude of about 8000 m. Unfortunately, repeat his success on Everest in 1957. Buhl failed. He suffered a tragic death.

For the first time, the Japanese climber Yasno Kato managed to climb the summit of Everest alone in May 1980. He became the first person to conquer Everest from the south and from the north. True, 38 people helped him before going on the assault, and he overcame only the last 600 m of height on his own. For this ascent, the brave climber paid with the amputation of frostbitten fingers. Nevertheless, in 1982, at the age of 33, he repeated his solo ascent to the summit of Everest, but already in the dead of winter - with strong wind and frost. The first winter ascent to the summit of Everest was made in February 1980 by Polish climbers Tsishe and Wielicki. The assault on the summit with the subsequent descent to the camp took them 14.5 hours. On the descent, they found the body of the climber Schmatz (Germany) - the fourth woman in the world who conquered Everest in 1979. She died of hypothermia and exhaustion after a cold night at an altitude of 8200 m. The first woman to summit Everest in 1975 is the Japanese Junko Tabei.

Velitsky also owns another record: in 22 hours he climbed the Broad Peak in the Himalayas (8047 m), gaining 3140 m in height, and returned without spending the night. To perform such intense work at high altitude, you need to have not only great physical performance, but also have excellent resistance to oxygen starvation.

Also interesting are the reserves of human tolerance for cold overnight stays (without a tent) in high altitude conditions. Here one cannot fail to note the endurance and courage of the English climbers Gaston and Scott, who, after climbing to the top of Everest in 1975, ran out of oxygen. The climbers tried to continue moving in the ensuing darkness, but got lost. Lack of visibility, cold and wind forced them to return to a small cave, which they dug on the ridge in the afternoon. Here they managed to warm some water on a stove, but soon the fuel ran out. All night the climbers struggled with the cold in conditions of oxygen deficiency at an altitude of 8750 m. In total, they did not eat and did not sleep for 30 hours in a row, but still found the strength to return to the camp at an altitude of 8325 m in the morning.

The triumphal single combat of a man with Everest can rightfully be called a single ascent to its summit by the conqueror of all 14 eight-thousanders, 35-year-old native of South Tyrol Rengold Messner, which he made in August 1980 without using an oxygen mask (for the first time in the monsoon period). By the way, it was Messner who, in 1978, made the first oxygen-free ascent to the summit of Everest, which, together with the descent, took 8.5 hours.

The beginning of the solo assault on the summit of Everest Messner began from a height of 6500 m, to which he climbed together with his girlfriend. Having left with a 15-kilogram backpack, he reached a height of 7800 m on the first day, and 8220 m on the second. On the third day, Messner went for a "walk" to the top of Everest without a backpack at all. Fortunately, his extremely risky ascent ended quite well.

Having made "the main ascent of his life", Messner did not feel like a hero at all. Here are his words from an interview given after the ascent: “August 18, I got up at 5 o'clock in the morning and moved up. Suddenly, a snow bridge collapsed, and I fell into a crack to a depth of 10 meters. Never before have I experienced such fear. I wanted to scream, call for help, but I knew that no one would lend a hand to me. Only a few hours later I got out of the crack. The second time I did not survive such torture. I did everything I could. I spent not only physical, but also all moral forces. The mountains appeared before me in a completely different light. I felt like I was in the enemy's camp. Gorges hostilely followed my every step, waited for mistakes and were ready to kill me ... I survived by accident.

However, those who know the mountains firsthand pay tribute to Messner's endurance and endurance.

It should be noted that, covering the success of Messner, not all the press was up to par. Appeals appeared in a number of newspapers: “If you are a man, test yourself on Everest”, “A million francs to the one who climbs Nanga Parbat alone during the insidious monsoons and uses a movie camera instead of an oxygen mask.” And after Messner, dozens of singles rushed to Kathmandu and Lhasa - the gates of international mountaineering.

However, only a few managed to achieve the goal. Others managed to turn back in time, and some disappeared without a trace in avalanche drifts, cracks, gorges and on glaciers.

And yet, the Himalayan giants, and especially Everest, continue, like a magnet, to attract the eyes of climbers from all continents.

Nowadays, the highest mountain peaks are conquered not only by climbers, but also by skiers. So, in the summer of 1979, 37-year-old Japanese skier Yuhiro Miura skied down Everest. Under a slope of 45 °, he developed a descent speed of more than 170 km / h. His brake parachute did not open, and the brave skier left the assigned route. Miura was saved only by a fall, which occurred a few meters from a giant glacial crack. Despite the fact that the fall occurred at a very high speed, the man remained alive and regained consciousness on his own.

In our country, in the summer of 1978, Olga Agranovskaya skied down Lenin Peak, which is over 7,000 meters high.

An obstacle to the settlement of high-mountainous regions is the temporary loss of the ability to bear children. For example, the first Spaniard was born only 53 years after the Spanish conquerors moved to the capital of Peru, Potosi, located in the Andes at an altitude of 3900 m. But the mountain climate contributes to longevity. It is among the inhabitants of the mountains that most often there are super-long-livers who have crossed the line of 150 years.

In the Azerbaijani village of Pirassura, located in the mountains at an altitude of 2200 m, Mahmud Eyvazov lived for 152 years (from 1808 to 1960). He exceeded the local record of longevity, which had previously belonged to his mother Agabane, by two years. Mahmud Eyvazov believed that the secret of his longevity lies in five conditions: a hardened body, healthy nerves and good character, proper nutrition, climate, daily work.

“My years are my allies in disputes about the “secrets” of longevity,” said Eyvazov. - I saw people bathing in a golden stream. They had a lot of bread, a lot of meat, a lot of rice... Their main concern in life was... to eat. The stomach swelled and grew fat, and the body was dying from lack of air, from selfishness and greed ... I saw and still see people who give all their strength and energy to our common cause, often working day and night. These are golden people, but they ruin themselves by lack of sleep, neglect of the daily routine, often forgetting to have lunch. We punish a person for violating the rules of our society, but we do not punish him for not hardening his body, for starting his illnesses ... in general, for violating the five conditions of longevity. But the strictest judge is life. And life is on the side of those who love it and cherish it!”

For comparison, it is interesting to cite other “five secrets of youth and longevity”, which are used by 83-year-old professor K. F. Nikitin from Sochi. Here they are: regular jogging (crosses up to 10 km) and athletic gymnastics, moderate nutrition, giving up bad habits, regular all-round hardening of the body, the predominance of an optimistic mood. As you can see, the "secrets" of Eyvazov and Nikitin have a lot in common.

There are reports that hermit yogis living in the Himalayas achieve long life spans. In principle, there is nothing surprising in this. After all, they comply with all five conditions of longevity. Moreover, the fifth condition they have has its own peculiarity: the daily work of these people is aimed primarily at the transformation of their own nature. And the results of such a transformation will not be slow to tell. For example, in 1955, at the age of 186, a hermit yogi named Tapasviji died. In 1819, he voluntarily resigned from the post of rajah in one of the Indian cities, and retired from the worldly sphere to the Himalayan mountains.

The philologist P. A. Afanasyev, now living in Taganrog, being a member of the UN commission, lived and worked in India for a long time, studied at one of the yoga schools and communicated with many of them. Some yogis living in the Himalayas, according to him, occasionally live even to 200-250 years.

Acclimatization to the high mountain climate is one of the effective ways to prevent premature aging. Science has numerous facts confirming this.

The Hunza Valley is located at an altitude of 2500 m in the Karakoram mountain range in Pakistan, far from the cities. The 32 thousandth population of this region does not know diseases. The average life expectancy of the Hunza at that time was 120 years! Mountain air, hardening, proper organization of work and rest, healthy food, mountain water and the absence of stimulants - this, according to Belvefer, is the secret of the health and longevity of the Hunza.

The French journalist Noel Barber, who visited the valley, described his meeting with 118-year-old Haider Beg, who had previously descended from the mountains, having traveled 10 kilometers. He could not have looked more than 70.

Hunza are vegetarians. In summer they eat raw fruits and vegetables, in winter - sun-dried apricots and sprouted grains, sheep cheese. The daily calorie content of the hunza diet averages 1933 kcal and includes 50 g of protein, 36 g of fat and 365 g of carbohydrates.

The Scottish physician Mac Carrison lived in the vicinity of the Hunza Valley for 14 years. He came to the conclusion that it is the diet that is the main factor in the longevity of this people. If a person eats improperly, then the mountain climate will not save him from diseases. Therefore, it is not surprising that the neighbors of the Hunza, living in the same climatic conditions, suffer from a wide variety of diseases. Their life expectancy is much less.

Mac Carrison, returning to England, set up interesting experiments on a large number of animals. Some of them ate the usual products of a London working family (white bread, herring, refined sugar, canned and boiled vegetables). As a result, a wide variety of “human” diseases began to appear in this group. Other animals were on a hunza diet and remained completely healthy throughout the experiment.

It is curious that the Hunza, unlike neighboring peoples, outwardly are very similar to Europeans. According to historians, the founders of the first Hunza communities were merchants and warriors from the army of Alexander the Great during his campaign through the mountain valleys of the Indus River.

There are only three regions on the globe characterized by a significant increase in the number of centenarians, and all three regions are mountainous. We have already talked about two of them. This is the Caucasus and the Hunza Valley in the mountains of Pakistan. The third region of longevity - the high-altitude valley of Vilcabamba - is located in the Andes (Ecuador).

When determining the longevity index (the ratio of the number of people aged 90 years and over to the total population over 65 years old), it was found that in countries with a predominance of mountains and mountain plateaus, this index is higher than in the plains.

Not only in the Caucasus, but also in the republics of Central Asia (Kazakhstan, Kyrgyzstan), there were 1.5–2 times more centenarians in the zone of the middle mountains than in the plains. Centenarians living at altitudes of 1600–2200 m (Issyk-Kul and Naryn regions) showed better health indicators and a higher degree of mobility than those living in the foothills (Chui Valley). True, it is important to take into account the nutritional factor. For example, a survey of centenarians in the mountainous regions of Georgia, conducted in 1984, revealed that 86.6% of their diet consists of longevity-promoting dairy and vegetable products. In the daily diet of centenarians with a calorie content of 1300-1800 kcal, the protein content was 50-61 g - almost like that of the Hunza.

Interestingly, the caloric content of the daily diet of the inhabitants of the Vilcabamba Valley is even less than that of the Hunza - 1200 kcal. They consume 35–39 g of protein per day, 12–19 g of fat and 200–260 g of carbohydrates.

Under the influence of adaptation to oxygen starvation in high altitude conditions, the body at rest develops the ability for more complete muscle relaxation, especially if hypoxia is combined with low air temperature (hypothermia). In acclimatized people at rest in the mountains, as a rule, there is a decrease in heart rate and a kind of “relaxation” of the central nervous system.

Of course, if an undertrained person puts himself under too much stress, the consequences can sometimes be sad.

The French scientist of the last century, Paul Ber, who experimented on himself and for the first time established that oxygen starvation is the basis of the effect on the body of a rarefied atmosphere, noted that in a pressure chamber, when the atmosphere is rarefied to a “height” corresponding to the top of the highest mountain in the Alps -

Mont Blanc (4800 m), he had a feeling of "mental relaxation". And here is how one of the participants in the 1972 international alpiniade described a similar state in the Pamir Mountains at an altitude of 5200 m: “Thoughts slid like a snow plateau under their feet. And in their place came emptiness. Huge, endless, ringing nothing... It turns out that if a person cannot think, this is tantamount to death. Downstairs, I guess it's called insanity. And in the mountains - oxygen starvation of brain cells.

Academician N. N. Sirotinin found that under the influence of hypoxia at high altitudes, "hypnoid phases" can occur in the cerebral cortex. In this regard, it can be assumed that hypnosis sessions in the mountains or with a rarefaction of the atmosphere in a pressure chamber will proceed more successfully than with normal oxygen supply to the body. But for self-hypnosis, hypoxia is probably not the best option. It is now firmly established that oxygen starvation impedes the process of thinking.

One of the founders of the Soviet school of aerospace medicine, V. V. Streltsov, wrote back in 1939: “The brain is the most sensitive organ to a lack of oxygen. Even with a very slight decrease in oxygen in the inhaled air, disturbances in the activity of the brain begin to appear, and then deepen. The thought becomes less clear. Decisions are made very late. The number of erroneous actions is increasing. Movements are not precise, not coordinated. The critical assessment of reality gradually decreases. At the same time, the subjective state, the state of health seems to be very good. V. V. Streltsov compared the effect of oxygen starvation with alcohol intoxication: both of them are first of all “applied” to the cerebral cortex.

It has been established that the intake of alcoholic beverages in the mountains quickly causes a state of intoxication. This is explained, on the one hand, by a violation of the oxidation of alcohol in oxygen deficiency, and on the other hand, by its faster absorption in the gastrointestinal tract.

At high altitudes (usually starting from 5000 m), mountain insomnia often bothers people. It is connected with an increase in blood flow to the head: by this the body, compensating for the lack of oxygen, provides normal nutrition to the brain. You can get rid of such insomnia by a simple method proposed by the Russian traveler N. M. Przhevalsky - to sleep with a very high headboard.

At rest, under the influence of adaptation to the mountain climate, there is a tendency to economization of physiological processes. This rule, however, does not obey the function of external respiration. The value of pulmonary ventilation, even with a long stay in the mountains, remains elevated compared to ground conditions. True, this shortcoming can be eliminated by systematic hypoventilatory training, as, for example, Tibetan lamas do.

Our studies have established that a person, having learned to breathe in flat conditions for 20 minutes at a rhythm of one breath per minute, can retain this ability even at an altitude of 4000 m. At this altitude, we also studied voluntary hypoventilation against the background of a 5-day food starvation . It turned out that the increase in ketone bodies in the urine during fasting in highlands is slower than in the plains. This is probably due to the fact that, as a result of hyperventilation caused by mountain hypoxia, a greater than usual part of the ketone bodies is excreted not through the kidneys with urine, but through the lungs with exhaled air. Physical performance for this period of food deprivation does not change significantly, and mental even increases.

The results of our experiment with 10-day fasting of people during the transition through the mountains of the Northern Tien Shan from Alma-Ata to Lake Issyk-Kul (about 100 km) are interesting. Three volunteers aged 30 to 47 all this time “feed” only water from mountain streams, although they carried backpacks weighing up to 28 kg (tent, medical equipment), and overcame two mountain passes 3600 and 3900 m high. Lake Issyk-Kul, they lost an average of 14% of their weight - 1.5 times more than during a 10-day fast in Moscow.

It is also interesting that throughout the route, the pulse, which was determined immediately after a night's sleep, was noticeably lower among the “starving” than among the tourists who accompanied them regularly. But before the start of the campaign, both the "hungry people" and their feeding companions had approximately the same pulse in the early morning hours. This means that the heart during fasting in the mountains works more economically than in the case of food intake.

And how long can a person do hard physical work in the mountains, eating almost only honey?

To answer this question, we set up an experiment on a group of six people aged 31 to 53 (including ourselves). The group consisted of four men and two women, and half of the participants in the experiment had no mountain hiking experience. And everyone had to go with backpacks weighing up to 25 kg (again, a tent and medical equipment) through the mountains of the Central Tien Shan for about a hundred kilometers, overcoming two passes with a height of 3650 and 3700 m. The daily food of the participants in this unusual trip consisted of only 5 glasses "compote", each of which included 1 teaspoon of fresh honey and 1-2 teaspoons of freshly prepared cherry or lemon juice, dissolved in melted water.

Only on the tenth day of this experiment, two of its male participants said that their physical capabilities had reached the limit. All the rest felt good. During their mountain trip, the participants of the experiment lost an average of 11% of their body weight, but quickly regained it on healthy food (berries, fruits, fresh milk, koumiss, low-fat cottage cheese). And not just restored body weight, but updated, improved the structure of body tissues, that is, as if rejuvenated.

If we talk about camping food for tourists, then, in our opinion, it is best for them to stick to the golden mean, that is, instead of canned food, refined sugar and salt, take nuts, dried fruits, honey, buckwheat, oatmeal and vegetable oil with them. On such a diet, we had to climb the northern deserted slopes of Elbrus and even climb the virgin snow to its eastern peak, carrying a triple tent.

In 1980, a group of mountain tourists from the city of Zelenograd near Moscow, being on a predominantly vegetarian diet, made a difficult 25-day hike through the mountains of the Central Pamir. The participants had to overcome four passes with a height of 5200–5600 m, two passes with a height of 6100–6150 m and climb the Fikkir peak with a height of 6700 m. During this trip, the tourists showed high sports results. And no wonder, because their backpacks weighed much lighter than with a standard diet.

In the winter of 1981, six vegetarian food enthusiasts went up to the Shelter of the Eleven hotel located on the slopes of Elbrus at an altitude of 4200 m. The daily diet of each of them consisted of 250 g of unpeeled nuts (walnuts, hazelnuts, pine nuts, almonds), 250 g of dried fruits (in the form of compote), 150 g of fresh carrots, 150 g of lemons and 80 g of honey. This set of products was sometimes supplemented with rosehip infusion and herbal tea from birch buds or string. This diet contained 26 g of protein, 67 g of fat and 250 g of carbohydrates - a total of 1500 kcal.

For four days, the climbers made training ascents from the "Shelter of Eleven" to Pastukhov's Stones, spending no more than 2 hours on it. And on the fifth day, the vegetarians challenged their fellow meat-eaters who were there.

Elbrus has become an arena of competition between representatives of two directions in the diet. The participants of this unusual competition had to climb the eastern peak of the two-headed giant. The team of vegetarians put up two of their best representatives, and the team of meat-eaters - six. The result of the competition was triumphant for the vegetarian athletes. Both of them were the first to climb the coveted peak.

In August 1982, another campaign of representatives of various Moscow health clubs took place in the Pamir-Alai mountains. Its main feature is the wide involvement of the elderly in mountain tourism. Six of the eleven participants were over 50, and the oldest (A.L. Kudlatova) was 68 years old. The eighteen-day hike, during which about 150 km were covered, included overcoming very high passes, one of which had to be stormed in the heat under the scorching sun, having only a flask of water for the whole day of the journey. It was also possible to cross the turbulent mountain rivers waist-deep in icy water. The reward for the participants of the campaign was a five-day rest in a picturesque corner of the mountains located at a three-kilometer altitude above sea level, where rare (due to the inaccessibility of the area) visitors have a whole gallery of natural hot mineral baths,

It is also curious that people who suffered from very serious ailments in the past took part in this campaign, which required great physical endurance and endurance. So, for example, 54-year-old doctor I.S. Pavlova was diagnosed in her youth with combined mitral heart disease with a predominance of stenosis. And only a healthy lifestyle over the past ten years with regular jogging, swimming, static gymnastics, hardening, proper nutrition has allowed her to achieve such a stable compensation for heart disease that she does not feel its consequences even when doing hard physical work in high altitude conditions.

Another participant in the campaign, 58-year-old teacher P.F. Silkin, in 1981 even dared to take part in the “hungry” transition of 11 people along the Valdai Upland, carried out under the supervision of doctors. In two weeks he walked 406 km without food.

And in the mountains, this man was in no way inferior to youth in physical endurance. Silkin connects the secret of his youth, health and creative activity (he is the author of the textbook) primarily with many years of experience in mountain tourism and eating mostly fresh plant products.

Unfortunately, not all participants of the campaign managed to complete the mountain route. Three left him in the first days. Moreover, they all preferred to eat mainly meat food. The diet of the rest of the tourists consisted of such vegetable sources of high-grade proteins as buckwheat, oatmeal, nut flour, green seasonings. To them was added a small amount of vegetable oil, crackers from whole-ground bread (Barvikha, doctor's, health), dried fruits, and honey. At times, the succulent fruits of wild apricot trees encountered along the way were a natural supplement to this diet.

And yet, rational nutrition alone is not enough to strengthen your body and spirit. For example, among the participants of a mountain hike, the representatives of the health club of acting gymnastics of harmonic perfection demonstrated the greatest endurance. And in this club, the focus is not so much on nutrition, but on developing the ability to form and maintain an optimally harmonious state in any life situations, acquiring the ability to use the reserves of positive emotions to the fullest.

V. Mamonov, a 55-year-old Muscovite, took part in one of our vegetarian hikes in the Caucasus Mountains, overcoming four high mountain passes and climbing to a height of 3700 m. Just five years before that, he suffered from cerebrovascular accident, sciatica, and was hospitalized with a cerebral stroke. The transition to a healthy lifestyle, which, in addition to a vegetarian diet, was based on an active and comprehensive regimen of physical activity, allowed him not only to successfully cope with all the difficulties of the campaign, but also for the first time in his life to run a marathon distance.

Even more surprising is the example of Muscovite A. Kudlatova, who at the age of 69 took the risk of taking part in a medical experiment: under medical supervision, make a difficult 15-day trek in the Pami-ro-Alai mountains, and even completely without food. The first five days of the hungry mountain hike were relatively easy. On the sixth day, Kudlatova's health deteriorated sharply. Too many unoxidized products of fat metabolism have accumulated in the body. It was not only hunger and constant physical exertion, but also a sharp shortage of drinking water. Kudlatova's companions had to lift her in a sleeping bag on ropes over sheer cliffs, and then lower her down a steep slope. Bile vomiting began. It was terrible to look at the haggard face of this woman, but she categorically refused the offer to start restorative nutrition. “I will start to recover only when I reach the apricot orchards,” Kudlatova said. And they were still very far away. Around - alpine meadows, and in front - a glacial pass almost 4 km high.

The next day, Kudlatova was already moving, although with outside help, then she walked again on her own, but without a backpack. Having spent the night on the 13th day of her journey in a tent on the pass, she deftly jumped over glacial cracks. Two days later, Kudlatova reached her goal and tasted apples and apricots, which the Kyrgyz shepherds treated her to.

In 1982, following our example, a “hungry” hike in the Caucasus Mountains was made by a group of tourists led by instructor N.N. Kalinin. Of the four "starving" three (two men and one woman), completely without food, made a 14-day transition of the second category of difficulty through five passes up to 3500 m high and with a total length of about 140 km. Only one "starvation" was forced to stop fasting on the eighth day of the campaign. The only indulgence for these tourists were light backpacks. In all other respects, they were not inferior in endurance to ten others who had been on a regular standard diet throughout the entire campaign. The first food that the brave trio took after her two weeks of deprivation was watermelons on the Black Sea coast.

In 1984, Muscovite E. Katkova traveled on a vegetarian menu in the Pamir-Alai mountains with her son Vasya, who was not even a year and a half old. She had to lift the child along mountain paths to a height of 2700 m on herself in a children's backpack. And a year later, in May, the control and rescue service, ascending from the south to the Kyrtyk-Aush pass in the Caucasus, was surprised to see E. Katkova descending towards them with her five-year-old son Alyosha. Before that, there had been heavy snowfall for almost two days. In order not to get stuck in snowdrifts and not fall into an avalanche, unusual travelers had to walk knee-deep in snow a little higher than the pass. And in total, on the route of 60 km, the mother and child overcame four passes.

Interestingly, the high-mountain porters of the Himalayan expeditions - Sherpas, who are known to have very high physical endurance, usually prefer to eat not high-calorie rations of mountaineering expeditions, but their national meager vegetarian food. Their typical menu is toasted barley products, lentils, etc.

It must be said that for climbers, even a diet of 5000 kcal/day usually does not cover energy expenditure when performing hard physical work in the mountains. This is partly due to the fact that in high altitude conditions, as a result of hypoxia, the work of the digestive glands is disrupted, and, consequently, the absorption of food is difficult. Thus, a decrease in the secretion of the salivary glands is already observed at an altitude of 3500-4000 m, the glands of the body and fundus of the stomach - at 4500 m, and its pyloric section - at an altitude of 6000 m. The intestinal glands are most resistant to oxygen deficiency. Their secretion is inhibited only at altitudes of 7000–8000 m. At the same time, as a result of increased ventilation, the loss of moisture through the lungs increases sharply. Against the backdrop of hard physical work, all this can lead to serious exhaustion. For example, one of the members of the Everest expedition in 1933, after a long stay at high altitudes, during which he climbed to 8743 m, without using additional oxygen nutrition, lost so much weight that he could clasp his thigh with the fingers of one hand.

In contrast to the state of rest, physical activity in the mountains, even in acclimatized individuals, causes a much more pronounced stimulation of the cardiovascular system and the respiratory apparatus compared to the conditions of the plain. Here is how, for example, the well-known Soviet climber E. Abalakov describes the effect of physical activity in the mountains on the human body: “As we climb, weakness seizes us. Every fifteen steps, the trained, hardy climber must rest and regain his breath. Shortness of breath torments even after the most easy work. It is enough to bend over and lace up your boot, put on a backpack, hammer in a hook - and again you need to accumulate strength for the next movement.

If short-term explosive efforts of maximum power at high altitudes in the mountains are still possible, then long-term high-intensity work is extremely difficult, and recovery processes after physical activity take longer there than at sea level. This is explained by the fact that oxygen deficiency does not affect the speed of energy release during the breakdown of the “accumulator” - adenosine triphosphoric acid (ATP). However, it slows down the “recharging” of this “accumulator”, i.e., slows down the process of ATP recovery from adenosine diphosphoric acid (ADP).

But even in the mountains, physical activity remains an important means of improving human health, a powerful catalyst for the process of mountain adaptation. The famous Sherpa, the “tiger of snows” N. Tenzing, who climbed the summit of Everest for the first time in 1953, said: “Continuously move, maintain blood circulation, fighting altitude sickness. I think this is one of the reasons why I never had a headache and vomiting.

Academician of the Academy of Medical Sciences of the USSR, laureate of the Lenin and State Prizes A. A. Letavet adheres to the same opinion. He is the only one in the galaxy of academicians who was awarded the title of Honored Master of Sports of the USSR. At the same time, it is worth noting that the most difficult journeys and difficult ascents were made by A. A. Letavet when he was over 40.

A 90 km run by a group of enthusiasts in the Himalayas, registered in 1985, testifies to the great reserve capabilities of a person. The path of the runners lay on average at an altitude of 4500 m. The average running speed was 8 km / h. It is noteworthy that only one of those who came to the finish line at an altitude of 5100 m climbed into the mountains higher than 5 km earlier.

In 1987, two English climbers managed to climb the five-thousander in Peru even on bicycles.

It is promising in terms of accelerating the process of adaptation to a high-mountain climate, a combination of physical exercises with an artificial limitation of the volume of pulmonary ventilation. Our studies have shown that in the mountains at an altitude of 4000 m, even under the influence of a six-day training in performing intense physical activity with limitation with the help of special vests, excursions of the abdomen and chest (decrease in lung capacity by 1 liter), exercise tolerance improves significantly.

But back to the mountain climate. Perhaps its main attraction is the crystal clear air, which is disinfected due to the abundance of life-giving sunlight and also has its own radiation. And yet in the mountains you can catch a cold and get sick. True, in mid-mountain conditions, colds can occur in a relatively mild form. This is explained by the fact that during hypoxia, white blood cells are activated - neutrophils, which "devour" the invading viruses. But the formation of antibodies - the main weapon against viruses and microbes - is disturbed in the mountains. And the higher we climb the mountains, the more difficult the infectious disease will be there.

This situation, however, is not hopeless. Studies conducted in the United States showed that in 56 out of 156 cases, with the help of a special training of the psyche - the so-called transcendental meditation - as a result of streamlining oxidative processes in the body, it was possible to normalize its immunobiological reactivity in infectious and allergic diseases. Perhaps this is used by Tibetan lamas, who are fluent in transcendental meditation. (The essence of transcendental meditation comes down to going beyond the limits of speculative interaction with the outside world, accompanied by the experience of identification with it against the background of the disconnection of the senses.)

Mountain air is dry, which increases the release of water through the body through the lungs and skin. This return increases even more under the influence of mountain winds. As a result, a kind of drying of the body occurs. Therefore, it is not surprising that, for example, during one of the ascents of Everest at an altitude of 8200 m, none of its participants had an urge to urinate during the day. And this is despite the fact that hypoxia under normal conditions increases the excitability of the nerve center of water metabolism.

To prevent dehydration at high altitudes in the mountains, it is recommended to increase fluid intake. The climbing team R. Messner-P. Habeler, during a successful oxygen-free ascent of Everest in 1978, daily consumed 5-6 liters of liquid, mainly in the form of tea, even in those cases when they were not thirsty.

Mountain air has one more feature - under the influence of ultraviolet radiation, air oxygen is ionized. But only negative oxygen ions, as the experiments of the remarkable Soviet scientist A. L. Chizhevsky showed, are able to maintain the normal functioning of the body.

Skillful use of mountain climate factors can undoubtedly contribute to health, prolongation of youth and human life. Once K. E. Tsiolkovsky dreamed that mankind would create an artificial mountain climate on board aircraft, and people would be able to “live in the mountains”, being anywhere in the universe. The latest research shows how reasonable this idea is.

Along with attempts to reach mountain peaks, the desire of people to descend into the water depths has long been known.

INTO THE DEPTHS UNDERWATER AND EARTH

Once, only the literary heroes of Jules Verne were able to travel to the depths of the sea, but in 1960 it was no longer the fantastic Nautilus, but a completely real bathyscaphe with two scientists on board (J. Picard and D. Walsh) reached the bottom one of the deepest trenches in the Pacific Ocean - 10,919 m.

Even in their wildest dreams, mankind could hardly count on such a success. Paying tribute to the audacity of researchers, one cannot but admit that such an achievement has become possible only in our days - thanks to the development of modern technology.

The depth of diving without scuba gear is limited primarily by the reserves of oxygen available in the body (about 2.5 liters). The diver is also helped by the fact that the pressure of the water, squeezing the blood from the limbs, increases its saturation in the lungs. So, for example, the Frenchman Jacques Maillol managed to reach a depth of 105 m without scuba gear. He plunged into the water along a cable at a speed of 10 m / s and then rose up at the same speed. One of the secrets of this phenomenon is that Maillol, by the time he set his new world record, had 10 years of experience in training according to the yoga system. He learned to perfectly relax his muscles and hold his breath for up to 4 minutes, increased his lung capacity to 7.4 liters. Thanks to such a long breath holding, the human body in the underwater depths, as it were, is likened to a bathyscaphe, i.e., as a result of turning off gas exchange, there is no problem of decompression disorders for the body, which we will tell the reader about later. It is also interesting that up to a depth of 50 m, Mayol dives with a nose clip, which prevents water from entering the nasopharynx. With further immersion, he removes the nose clip, and then, due to the penetration of water into the nasopharynx, the barometric pressure is equalized on the outer and inner sides of the eardrums. This eliminates the unpleasant sensation in the ears associated with the one-sided pressure of water on the eardrums. Maillol's eyes in the underwater depths are protected by contact lenses.

Among women, the young Italian diver Angela Bandini achieved brilliant success in 1986.

Near the island of Elba, she dived without scuba gear to a record depth for women - 52.5 m. The whole operation took 2.5 minutes. And five years earlier, Bandini had dived 20 meters into the icy waters of a lake lying at a five-kilometer height in Pery.

Speaking of underwater records, one cannot but recall the heroism of Shavarsh Karapetyan, a multiple world record holder in diving. When in 1982 a trolleybus with 20 passengers fell and sank in the cold waters of the Yerevan reservoir at a depth of 8–9 m, Karapetyan dived to the bottom in a row for more than 20 minutes and saved the lives of all the victims. After that, he also helped pull out the trolleybus itself. It was both a civilian feat and an unofficial sports record.

But the record for the penetration of scuba divers into the depths of the sea is 565 m. It was set in 1972 by two Frenchmen.

In 1986, the American Jay Smith managed to stay under water with scuba gear for 124 hours 30 minutes, and his compatriot Fay Henry - more than 72 hours. At the same time, they used an air bell to rest and eat.

The book by M. V. Vasiliev “Matter” (1977) describes how four volunteers managed to withstand the barometric pressure corresponding to a depth of 1520 m in a pressure chamber! They spent 4 hours at such a “depth” without any harm to themselves, and this at a barometric pressure 152 times higher than the pressure on Earth. If, at normal atmospheric pressure, a person is offered to breathe with a mixture containing 99.86% helium and 0.14% oxygen, then he will lose consciousness due to oxygen deficiency in 1–2 minutes. But at a barometric pressure corresponding to a sea depth of 1.5 km, a person will be able to freely breathe this mixture in the same way as he breathes atmospheric air under normal conditions. Conversely, breathing atmospheric air at a pressure of several tens of atmospheres is deadly. Under these conditions, the body will be poisoned by nitrogen and ... oxygen. Yes, yes, with the same oxygen that saves lives in other cases. Excessive oxygen saturation leads to serious, sometimes irreversible changes in the body.

In our country in 1985, four volunteers lived for more than a month in a pressure chamber at a “depth” of 450 m. At the same time, Arctic divers began to carry out underwater technical work on the seabed, being at a depth of 300 m continuously for 1.5 hours.

With a significantly increased barometric pressure, not only the oxygen of atmospheric air becomes life-threatening, but also the nitrogen contained in it. This gas dissolves perfectly in the nervous tissue, causing first a narcotic and then a toxic effect. Nitrogen anesthesia, or "deep intoxication", usually occurs if a person breathes atmospheric air at a depth of 30-100 m. In this state, he loses control of himself. There are cases when scuba divers in a state of "deep intoxication" took out a mouthpiece with a hose from their mouths, through which air was supplied from the cylinders, and died. Therefore, when a diver dives to a great depth, he is given a gas mixture, where nitrogen is replaced by helium, which dissolves much worse in the nervous tissue and in the blood.

Replacing nitrogen with helium helps the diver avoid the so-called decompression sickness when ascending to the surface of the water. It arises mainly due to the fact that during a rapid rise, an additional amount of nitrogen dissolved in the blood, tissue fluid and tissues does not have time to be released from the body. Gas bubbles appear in the blood, which can lead to blockage of vital vessels.

A great contribution to overcoming this physiological barrier was made in the 50s. young Swiss scientist Hans Keller. The essence of his idea is the successive change of different gas mixtures during ascent. At a depth of 300 to 90 m, he suggests breathing a mixture of helium and oxygen, from 90 to 60 m - a mixture of nitrogen and oxygen, from 60 to 15 m - an argon-oxygen mixture, and from 15 m to the surface of the water - pure oxygen. Having set up an experiment on himself, Keller rose from a depth of 222 m in just 53 minutes. But it took 12 hours to reach it from a depth of 180 m!

Decompression sickness can occur not only when ascending from the depth to the surface of the water, but also when the atmosphere in the pressure chamber is rapidly rarefied. In our practice, there was a case when a person breathed oxygen through a mask in a pressure chamber at an atmospheric rarefaction in it, corresponding to an altitude of 11000 m, and at the same time performed work on a bicycle ergometer up to 1000 kgm/min. On the 26th minute of work, he developed decompression pains in his left knee. Not attaching importance to them, the volunteer continued to work. After another 5 minutes, gas bubbles began to clog the large vessels of the lungs. As a result, despite breathing oxygen, there was a feeling of sharp suffocation, the person even lost consciousness. In just 3 minutes, the barometric pressure was normalized in the pressure chamber, and then the victim was even “immersed” in the hyperbaric chamber to a “depth” of 15 m, where he stayed for 1 hour. However, the state of health continued to deteriorate, and blood pressure dropped to 50/0 mm Hg. Art. Only after resuscitation and two weeks of inpatient treatment, all the consequences of decompression sickness were completely eliminated.

By the way, in order to reduce the likelihood of divers getting decompression sickness when they quickly rise to the surface of the water, one could recommend ... to engage in high-altitude mountaineering. In our observations of eight volunteers who performed hard physical work on a bicycle ergometer while breathing oxygen in a pressure chamber “at an altitude” of 11,000 m, all without exception developed decompression joint pains at 13-35 minutes of work. After a real ascent of Elbrus, one of the same volunteers developed decompression pains not on the 18th, but on the 39th minute of work. For the rest, they did not appear, despite continuous work for 1 hour.

In general, in order to more easily overcome various kinds of barriers that a person encounters in the water, it is advisable to start underwater training of the body from infancy. Newborns have a fairly high resistance to oxygen starvation. And this is not surprising, given that in the mother's body the fetus receives an amount of oxygen approximately the same as at the height of Everest.

Under our supervision there was a cat, which, two days before the birth of kittens, was “raised” in the pressure chamber to an “altitude” of 12,000 m and stayed on it until complete cessation of breathing (18 min). Despite such a pronounced hypoxia, the cat had six full-fledged kittens. In another experiment, it was found that a newborn rat lives in an anoxic gaseous environment (in pure nitrogen) for 50 minutes. If, artificially, with the help of the introduction of iodoacetate, glycolysis is inhibited, then its lifetime is reduced to 3 minutes.

Observations on children carried out in recent years have shown that newborns with whom scuba diving lessons are taught much faster to not breathe underwater for a long time than older children and adults. This is explained by the fact that newborns have a greater ability to obtain oxygen-free energy than an adult.

An employee of the Institute of General Pedagogy and Psychology I. B. Charkovsky set up an interesting experiment on his 7-month-old premature daughter. The girl weighed only 1600 g. In order to somehow facilitate her premature transition from the conditions of immersion in the mother's womb to the conditions of Earth's gravity, to which it is rather difficult for a premature organism to adapt, Charkovsky periodically placed his daughter in an aquarium and kept her there for several hours. The girl, to everyone's surprise, felt like a real ichthyander in the water element, swam and dived freely, and at the age of 4 months she already had a normal weight.

Australian swimming coaches, the Timmermans, began teaching their son how to swim from the end of the first week after birth. By six months, the child could stay on the water for up to 15-20 minutes, and swim several hundred meters.

It has now been established that the reflex of blocking the breath when immersed in water is much stronger in a newborn than in an adult. It has also been proven that infants have not yet lost the ability to navigate in the aquatic environment with the help of the most ancient analyzer - taste. "To taste" a child under water can even distinguish people close to him from strangers.

The Soviet academician S. I. Volfkovich, already an elderly man, once during a sea storm in Gagra, risking his life, saved a drowning man. In response to the gratitude of the saved, he replied: “What are you thanking me for? You owe your life not to me, not to me ... But to the fact that I had wonderful parents who taught me to swim at the age of two.

In 1982, the city of Tutukaka (New Zealand) hosted the first scientific conference dedicated to the birth of children in water. To date, hundreds of children have been successfully born under water in the USSR. As of January 1982, 52 such births were registered in France, and 15 in the USA. Of course, such births are taken by experienced doctors. The water bath is thoroughly disinfected, the temperature of the water is the same as the temperature of the mother's womb (approximately 38.5 ° C); 0.5% salt is added to the water, i.e. the same amount as it is in the blood plasma. So the child is born in a familiar aquatic environment. The cool air does not touch the skin of the child, which would prompt him to start breathing. At the same time, the woman in labor, as a rule, experiences not very strong pain sensations, and the child does not receive a birth injury.

Interestingly, thousands of years ago in ancient Egypt, when a woman was threatened with difficult childbirth, she was lowered into the water. Perhaps it was precisely such cases that made it possible to notice that children born in water were ahead of their peers in physical and mental development. And then those who were to become priests began to be born in the aquatic environment.

An interesting story happened in our country in July 1986 with the Bagryansky spouses from the city of Vladimir. They rested in the Crimea in the Sudak region, waiting for the replenishment of their family. A normal birth occurred during a morning dip in crystal clear sea water. Born in such exotic conditions, the girl was given the exotic name Eya.

Sondra Ray's The Perfect Birth (1985) describes a similar incident that happened in 1966 with Neville von Schleffenberg. His 23-year-old mother was swimming in the ocean when she went into labor Baby was post-birth in water 4-5 minutes.

There are projects (and they are planned to be implemented in the not too distant future) for the construction of underwater cities. And separate underwater laboratory houses already exist in many countries of the world. Back in 1969, the maximum diving depth was reached by the American underwater laboratory "Aegir" - 158.5 m. Six aquanauts were in it for 5 days.

The atmosphere of the underwater house "Aegir" contained only 1.8% oxygen, but the barometric pressure was much higher than on the earth's surface.

If, for example, at such a low oxygen content, the barometric pressure is increased to 10–11 atm, then the body will not feel any oxygen deficiency. It is the increased barometric pressure of the air that distinguishes underwater houses from submersibles. After all, their inhabitants - aquanauts - periodically have to go out in their spacesuits into the underwater world, that is, into conditions where the barometric pressure reaches even higher values. If in underwater houses the barometric pressure was maintained the same as on the earth's surface (and in the bathyscaphe), then aquanauts would have to wait too long in the “hallway” of their dwelling after each underwater walk in order to avoid decompression sickness.

At the II International Conference on the study of human activity under water, French researcher Jacques Yves Cousteau suggested that the underwater cities of the future could be inhabited by people with artificial gills that extract oxygen directly from the water. In accordance with this idea of ​​Cousteau, in order to counteract pressure at depth, the lungs should be removed from a person, and a special cartridge should be introduced into his circulatory system, which would chemically release oxygen into the blood and remove carbon dioxide from it. Further, according to Cousteau, the fight against decompression sickness and free movement along the seabed will be facilitated by filling the body cavity with an inert liquid. All this will characterize a new kind of man - "homo aquaticus". Cousteau did not rule out that the first man of this species would appear by 2000.

In principle, homo aquaticus could do without gills, but for this he would have to live at a depth of 500–700 m. voltage, will be enough to breathe ... water. One dog was able to return to earthly life again.

In our opinion, humanity will explore the underwater depths not quite the way Cousteau suggests. This would be a step back. Indeed, the secondary return of mammals to the aquatic environment, which led to the appearance of modern seals, walruses and whales, is not associated with the appearance of gills in them. But these animals have an amazing ability to economically consume oxygen. A person also develops the same ability through special training. With the help of special training and technical devices, a person will increase the resistance of his body to decompression and cooling associated with increased heat transfer in the water, learn to dive and swim like dolphins. But man will never turn into a special, exceptional species of "homo aquaticus". He will develop harmoniously and feel equally free in the water element, on land and in space.

In our time, a person successfully storms not only underwater, but also underground depths. First of all, this applies to cave explorers - speleologists.

The famous French speleologist Michel Sifre, at the age of 17, dived into caves with a depth of 320 to 450 m for 81 hours. spent two whole months alone in the underground glacier, in darkness (by the light of a very weak electric bulb), at an air temperature of about 0 ° C, 100% humidity, in conditions of constant landslides. This is how he described his feelings in the cave: “My ears were constantly saturated with music or the fantastic roar of landslides. However, my visual perceptions were severely limited by the darkness. Pretty soon my eyes began to tire from the lack of natural light and weak electric lighting, and I felt that I was losing my idea of ​​colors. I began, for example, to confuse green with blue. It was difficult for me to determine the distances to objects ... Sometimes I had visual hallucinations.

In 1972, Sifre lived in a cave in Texas even longer - about 7 months. Interestingly, in the caves, his “day”, measured by the time intervals between two awakenings, was 24.5 hours, and his body temperature did not exceed 36 ° C.

Such auto-experiments can only be compared with the Antarctic loneliness of American Admiral Richard Byrd. In 1934, during the polar night, he found himself cut off from people for many months, in conditions of terrible cold (at the Antarctic base near 80 ° south latitude). Nevertheless, courage did not leave Byrd, and in single combat with darkness and cold, he emerged victorious.

Underwater floods are among the serious dangers that await a person in caves. Here is how one of them is described in Norbert Castere's book My Life Underground. In 1951, Dr. Merey found himself with 6 comrades in one of the caves of the Jura, when an underground flood suddenly began. Panic arose in the detachment, and everyone rushed to run, trying to overtake the rise of water and get to the exit from the cave, but six of the seven members of the detachment were overtaken by water and drowned.

Dr. Merey tried to keep his cool and decided to stay in place, where the vault was higher and, moreover, formed a kind of recess. His calculations could not be justified, since the water reached his shoulders and, moreover, he constantly had to fight with a turbulent current. The water receded only after 27 hours. Merey was completely exhausted from cold and fatigue, but continued to struggle with water and resisted.

Interestingly, some caves can be successfully used for medicinal purposes. For example, in the Solotvino salt mines of Transcarpathia, since 1968, patients with bronchial asthma have been treated with overnight stays in caves. Medical statistics show that 84% of adults and 96% of children get rid of bronchial asthma in this way. The healing effect of these caves is explained by the purity of the air and its pronounced negative ionization.

The deepest of the caves studied to date is the Jean-Bernard cave in France - 1445 m. It is believed that the Snezhnaya cave in the Caucasus has a depth of 1600 m. South Africa. At such great depths, people mine gold.

So, we have seen that a person has a huge supply of hidden reserves. You just need to learn how to use them. A mature young organism has a particularly rich reserve capacity. But youth is not only a concept of age. We will now move on to talking about how individuals manage to overcome age barriers.

Compared to other mammals, we mature very slowly. According to medical criteria puberty in humans, it begins at the age of 12-13, the teenage period lasts until 17-18 years. After that, girls usually no longer add in height, and boys can grow up to about 26 years. That is, a significant part of life is allotted to us for growth and development.

Small animals grow faster, large ones slower. But even if we compare us not with rapidly growing and breeding mice, but with mammals of a more solid size, the difference is obvious. Cats and dogs live 15-20 years, but on average they reach the size of an adult animal in a year, and puberty occurs even earlier. The horse lives up to 25-30 years, and reaches full development in 4-5 years. In an elephant, which is comparable in life expectancy to a person (60-70 years), puberty occurs at 8-12 years. Finally, our closest relatives, chimpanzees, reach sexual maturity at 6-8 years old.

And in terms of the rate of growth in childhood, a person, as the authors of the article note, is more similar not to mammals, but to reptiles that grow all their lives, but very slowly. Boys and girls begin to rapidly stretch at puberty (from 12-13 years old), and before that, the increase in growth is much less noticeable.

Anthropologists from Northwestern University tried to solve the riddle of slow human growth, and they wrote in Proceedings of the National Academy of Sciences .

It turned out that with slow growth, a person pays for his large brain, which devours the lion's share of energy.

For the first time, scientists have studied in detail the development of a person from birth to adulthood, using different methods of brain scanning - PET (positron emission tomography) and MRI (magnetic resonance imaging). With these methods, they measured brain volume and glucose consumption, that is, energy expenditure. And then they compared these indicators of the brain with the growth of the body.

Until now, it was believed that the brain absorbs the most energy in a newborn baby, since the ratio of brain size to body at this moment is maximum. But researchers have now calculated that

The brain absorbs the maximum amount of glucose at the age of 4-5 years. During this period, the energy expenditure of the brain is 66% of metabolic energy at rest.

This is much more than our closest relatives, the great apes, spend on brain development.

And it turned out that during this period the growth of the body slows down greatly. It turns out that the brain simply "eats" the rest of the body, there is not enough energy for growth.

“After a certain age, it becomes difficult to determine the age of a child by his height,” notes Christopher Kuzava, the first author of the study. - We can rather judge the age by his speech and behavior. Our work has shown why this is so. When the brain develops most rapidly, the growth of the body almost stops, because the brain takes all the resources.

As the researchers explain,

at the peak of energy expenditure in the brain, the number of synapses, contacts between nerve cells, increases to the maximum.

Such a network of contacts enables a child at this age to learn a lot of things that he will need in the future.

A large brain is generally expensive for a person, and the first inconvenience that he experiences is a difficult birth, since the newborn has a large head. And in order to acquire the most complex system of contacts between neurons, the human brain needs a lot of energy (caloric food) and a long period of development. During a long childhood, a child learns a lot of different things that make a person a person, first of all, of course, he masters speech. Long childhood also dictates the peculiarities of human family relations: parents take care of the child for a long time and at the same time not only raise him, but also educate and teach.

Another detail of the life of man and great apes attracted the attention of scientists and gave rise to a hypothesis. Unlike the vast majority of mammals, women and females of higher primates live quite a long time after the end of the reproductive period, that is, after the onset of menopause. From the point of view of biology, life after reproduction is useless, as resources are spent, and reproduction does not occur.

To explain this phenomenon in humans and other higher primates.

Females who are past reproductive age begin to "work as grandmothers" and help their daughters raise their children. In doing so, they increase the survival rate of these children, increasing the chances of preserving and passing on their genes.

And children with parental and grandmotherly care can remain small and helpless for quite a long time, which gives them the opportunity to grow a big brain and develop intelligence. The circle is closed, you can read again.