LECTURE II CANDLE. BRIGHTNESS OF THE FLAME. AIR IS REQUIRED FOR COMBUSTION. FORMATION OF WATER In the last lecture, we looked at the general properties and location of the liquid part of the candle, as well as how this liquid gets to where the combustion takes place. Did you make sure that when the candle

Locally produced air Since the inner planets - Mercury, Venus, Earth and Mars - are located close to the Sun (Fig. 5.2), it is quite reasonable to assume that they are composed of the same raw materials. And there is. Rice. 5.2. Orbits of planets in the solar systemView to scale

How much air do you inhale? It is also interesting to calculate how much the air that we inhale and exhale during one day weighs. With each breath, a person introduces about half a liter of air into their lungs. We do in a minute, on average, 18 breaths. So for one

How much does all the air on Earth weigh? The experiments now described show that a column of water 10 meters high weighs as much as a column of air from the Earth to the upper boundary of the atmosphere - that's why they balance each other. It is easy to calculate, therefore, how much

Iron vapor and solid air Isn't it a strange combination of words? However, this is not nonsense at all: both iron vapor and solid air exist in nature, but not under ordinary conditions. What conditions are we talking about? The state of matter is determined by two

THE FIRST ATTEMPT TO GET A SELF-ACTIVE ENGINE - A MECHANICAL OSCILLATOR - WORKING BY DEWAR AND LINDE - LIQUID AIR Realizing this truth, I began to look for ways to implement my idea, and after much deliberation, I finally came up with an apparatus that could receive

51 Tamed lightning right in the room - and safe! For the experience we need: two balloons. Everyone saw lightning. A terrible electric discharge strikes directly from the cloud, burning everything it hits. The sight is both scary and attractive. Lightning is dangerous, it kills all living things.

HOW MANY? Even before she began studying uranium rays, Maria had already decided that prints on photographic films were an inaccurate method of analysis, and she wanted to measure the intensity of the rays and compare the amount of radiation emitted by various substances. She knew: Becquerel

When we lift a bucket filled with water, we immediately feel its great weight. Lifting a bucket without water, we feel only the weight of the vessel itself. But this bucket is not empty, it is filled with air; so the air itself has no weight? Maybe the air in the bucket weighs nothing because it escapes from the open bucket. Let's take a wineskin or a bull's bladder, fill it with air, tie it up and try to weigh it, and then squeeze the air out of it and weigh it again. It turns out that the readings of the scales will be the same both times, maybe, really, the air weighs nothing and can this be considered proven? At the same time, if we agree with the absence of the weight of air, then many phenomena will seem incomprehensible.

Why, for example, medical cups retract human skin. Why, if we fill a glass with well-polished edges exactly to these edges with water and cover it with a piece of paper, and then quickly turn the glass over, will the water not pour out of the glass? Why does a pump that pumps water from the bottom up work?

All these phenomena seemed inexplicable for a long time, but the pump also made it possible to discover the truth.

In search of an explanation, they turned to the famous scientist Galileo, then an 80-year-old elder. Two variants of further events have come down to us. According to the first of them, Galileo seemed to be embarrassed and did not know what to answer. According to the second version, Galileo weighed the "empty" bottle, then warmed it up strongly, closed it with a cork and, having cooled, weighed it again. It turned out that this time the bottle weighed less. Information has been preserved that in the 17th century a pump was built in the garden of the Duke of Tuscany in Florence to pump water for a fountain to a height of more than 10 meters, but this did not work out. The pump was made as well as all the others, which worked perfectly, and therefore the failure with it seemed completely incomprehensible.

Galileo correctly explained the decrease in the weight of the bottle by pointing out that when heated, the air expanded and was forced out of the bottle into the atmosphere. Consequently, there was less of it in the bottle, and therefore the weight of the bottle became smaller for the second time. Thus, Galileo established that air has weight, but it weighs less than water, and the new pump, larger than the previous ones, did not work only because the weight of the outside air did not balance the too high column of water.

Undoubtedly, the second version of the story that has come down to us is more correct, since it is known that Galileo had already made similar calculations before. He explained the force that balances the pressure of the air with the "power of emptiness". In those days, there was an opinion that nature was "afraid of emptiness", and as soon as a void forms somewhere, nature immediately fills it. But at the same time, it remained inexplicable that this “fear of emptiness” stopped above 10 meters. Consequently, the mystery has never been fully resolved.

A student of Galileo, Torricelli continued to study the issue and made a series of experiments that allowed him to reliably prove that air has weight, and led him in 1643 to the invention of an instrument now known to us under the name barometer . Torricelli filled a glass tube 100 centimeters long closed at one end with mercury and immersed its open end in a vessel with mercury. At the same time, the mercury did not completely pour out of the tube, but, having lowered a little, stopped at a level of about 76 centimeters; Torricelli correctly concluded that mercury is supported in the tube by the weight of the outside air.

The air pressure on the surface of the mercury in the cup is balanced by the pressure of the mercury column.

For several years, Torricelli's conclusions were not confirmed. Finally, in 1647, the French scientist Pascal decided to finally clarify this issue. He turned to his relative Perrier, who lived in the city of Clermont, at the foot of the Pew de Dome mountain, with a request to make the necessary observations. Pascal's request was fulfilled on September 19, 1648, and from that date the fact that air has weight ceased to be in doubt.

Perrier did just that. He prepared two identical Torricelli tubes and, having measured the height of the mercury column in the tubes at the foot of the mountain, left one of them in place, and climbed to the top with the other. At an altitude of 975 meters, he again measured the height of the mercury in the tube. It turned out that at the top it was 8 millimeters lower than at the foot of the mountain.

Amazed by the result, Perrier checked his measurements many times and, only finally convinced of their correctness, went downstairs. In the tube below, the mercury remained at the same level. At the same level, she stopped in the tube brought from above.

Thus, it was finally proved that air has weight and therefore it presses with more force in the lower layers than at the top, where a smaller amount of it remains above the observer's head. Air presses on the surface of the Earth with the same force that would press a layer of water 10.3 meters thick. That is why the pump of the Duke of Tuscany, raised above the water level above 10 meters, did not work. Mercury is 13.6 times heavier than water. Therefore, it was installed in the Torricelli tube at a height of about 76 centimeters (76x13.6 = 1033.6 centimeters). Air pressure also explains the action of a medical jar, as well as the fact that water does not pour out of an inverted glass, but closed with a piece of paper.

We do not notice this large air weight, since the human body has adapted to it and feels fine in these conditions. All the internal organs of a person are filled with air, which has the same pressure as the pressure of the atmosphere at the surface of the Earth outside our body; this internal pressure balances the external one. Climbing high in the mountains or on an airplane, a person strongly feels a decrease in air pressure with height (Fig. 2) and endures the decrease that occurs at the same time only to a certain limit, after which a feeling of suffocation or even death occurs.

Fish living in the ocean at great depths have adapted to even greater pressure, which is made up of the weight of the atmosphere and the weight of a huge mass of water. Caught at great depths and raised to the surface of the sea, fish die: they are torn apart by internal pressure that is not balanced by external pressure.

Why don't we feel the weight of air when we lift a bucket full of air? Yes, because we weigh it in the very same air. Similarly, when we lower a bucket into a well and fill it with water, we do not feel the weight of the water in the bucket. But it is enough to lift the bucket from the water into the air, as soon as its heaviness is felt.

One cubic meter of air weighs 1.3 kilograms, and the entire atmosphere surrounding the globe weighs 5,300,000,000,000,000 tons. As you can see, air weighs a lot, a lot. The weight of 1 cubic meter of air, equal to 1.3 kilograms, we get when we weigh the air at sea level and at a temperature of 0 °. The higher from the Earth's surface, the less air density becomes and the weight of 1 cubic meter decreases. So, at an altitude of 12 kilometers, 1 cubic meter of air weighs 319 grams, that is, four times less than below; at an altitude of 25 kilometers - 43 grams, and at an altitude of 40 kilometers - only 4 grams (Fig. 3). The increase in air density downwards and its rarefaction at the top are determined by gravity. But no matter how rarefied the air, like a gas, it fills all the space provided to it and, consequently, spreads far upwards from the surface of the Earth.

To what heights does the earth's atmosphere extend? And is it possible to establish its boundary at all, or is the air density gradually fading away?

The second assumption is correct, but nevertheless, theoretically, we can establish the boundaries of the air ocean. This is not difficult to do, since we know the weight of all the atmosphere above our head, and we can calculate the weight of a cubic meter of air at any height.

If the air at all altitudes had the same density as at the surface of the Earth, then the average height of the air envelope surrounding the globe would be close to 8 kilometers. But the density of air decreases rapidly with height, and therefore the height of the atmosphere must be many hundreds of times greater.

Even M. V. Lomonosov analyzed the question of the height of the earth's atmosphere. He reasoned like this. Air is made up of countless tiny particles called molecules. Gas molecules are in continuous motion, rushing up, down, to the sides. Below, where the air is dense and the number of molecules is enormous, they constantly collide with each other and, as it were, "push" in place. The higher, the fewer molecules in the same volume of air, and the path they fly from one collision with a neighboring molecule to another is longer. At the same time, air molecules located at high altitudes often fly down to the Earth; they fall under the influence of gravity, like all other bodies. The fall continues until it collides with molecules located below, in denser layers. Repulsed from them, the falling molecule flies upward again. Such a movement - up and down - all the molecules do countless times. But the molecule moves upward only up to a certain level. This level is determined by the force of gravity, due to which all bodies fall to the Earth, move along its surface and are not carried away from it into the world space. Only those molecules jump out of this level and leave the atmosphere which, at a high altitude, received a push of such a force from a collision with a neighboring molecule that exceeds the force of gravity at this altitude.

Later studies confirmed the correctness of M. V. Lomonosov's reasoning and showed that such a theoretical boundary of the earth's atmosphere lies above the pole at an altitude of 28 thousand kilometers, above the equator at an altitude of 42 thousand kilometers, that is, more than four and seven times the earth's radius.

We, the inhabitants of the earth, are primarily interested in the height of those layers of the atmosphere that still have a measurable density and where those meteorological and physical phenomena take place that we have the opportunity to observe and with which we must reckon.

From this point of view, the height of the earth's atmosphere will be determined by a layer 800-1000 kilometers thick.

Perrier measured the pressure of the atmosphere by the height of a column of mercury in a Torricelli tube, determining its length in millimeters. This method of measurement has been preserved to this day. Modern mercury barometers, in principle, are no different from the Torricelli tube. They are only more technically perfect, which allows you to make readings very accurately, capturing the smallest (up to 1/10 of a millimeter) changes in the height of the mercury column.

As we already know, at sea level, atmospheric pressure on average corresponds to the pressure of a mercury column 760 millimeters high. But this value does not remain constant. In different places at different times of the year and with different weather, it varies widely. The extreme pressure values ​​\u200b\u200bnoted so far are 680 and 802 millimeters.

Changes in air pressure play a significant role in weather phenomena. But this role is still not decisive. Therefore, it is impossible to predict the “weather using the measurement of only one pressure. Therefore, one should not attach much importance to the inscriptions on some metal aneroid barometers: “storm”, “rain” or “dry”. We can easily agree with this if we recall Perrier's experiment described above: the barometer changes its readings not only from the state of the weather, but also from the height at which it is currently located. This property is widely used in aviation, where, according to the readings of the same aneroid barometer ( altimeter ) determine the height of the aircraft.

To facilitate readings, the altimeter scale shows not the pressure value, but the corresponding height.

For a number of theoretical calculations, it is much more convenient to express the value of air pressure not by the length of the mercury column, therefore, not in millimeters, but in units of pressure. The bar is taken as such a unit, equal to the pressure of a million din 2 per 1 square centimeter, which corresponds to the pressure of a mercury column 750.1 millimeters long. In practice, one thousandth of a bar is used - a millibar. The pressure of a mercury column 1 millimeter long is 1.333 millibars. Accordingly, 1 millibar is approximately equal to 0.75 millimeters of mercury. At present, millibars are almost universally used in meteorology, but since the scales of most barometers are made in millimeters, the reading of the pressure value using special tables is then converted to millibars.

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Air is an intangible quantity, it is impossible to feel it, smell it, it is everywhere, but for a person it is invisible, it is not easy to find out how much air weighs, but it is possible. If the surface of the Earth, as in a children's game, is drawn into small squares, 1x1 cm in size, then the weight of each of them will be 1 kg, that is, 1 cm 2 of the atmosphere contains 1 kg of air.

Can it be proven? Quite. If you build a scale from an ordinary pencil and two balloons, fixing the structure on a thread, the pencil will be in balance, since the weight of the two inflated balloons is the same. It is worth piercing one of the balls, the advantage will be in the direction of the inflated ball, because the air from the damaged ball has come out. Accordingly, simple physical experience proves that air has a certain weight. But, if we weigh the air on a flat surface and in the mountains, then its mass will be different - the mountain air is much lighter than the one we breathe near the sea. There are several reasons for different weights:

The weight of 1 m 3 of air is 1.29 kg.

• the higher the air rises, the more rarefied it becomes, that is, high in the mountains, the air pressure will not be 1 kg per cm 2, but half as much, but the content of oxygen necessary for breathing also decreases exactly by half, which can cause dizziness, nausea and ear pain;
• water content in the air.

The composition of the air mixture includes:

1. Nitrogen - 75.5%;

2. Oxygen - 23.15%;

3. Argon - 1.292%;

4. Carbon dioxide - 0.046%;

5. Neon - 0.0014%;

6. Methane - 0.000084%;

7. Helium - 0.000073%;

8. Krypton - 0.003%;

9. Hydrogen - 0.00008%;

10. Xenon - 0.00004%.

The number of ingredients in the composition of air can change and, accordingly, the mass of air also undergoes changes in the direction of increase or decrease.

• Air always contains water vapor. The physical pattern is that the higher the air temperature, the more water it contains. This indicator is called air humidity and affects its weight.

How is the weight of air measured? There are several indicators that determine its mass.

How much does a cube of air weigh?

At a temperature equal to 0 ° Celsius, the weight of 1 m 3 of air is 1.29 kg. That is, if you mentally allocate space in a room with a height, width and length equal to 1 m, then this air cube will contain exactly this amount of air.

If air has weight and weight that is palpable enough, why doesn't a person feel heaviness? Such a physical phenomenon as atmospheric pressure implies that an air column weighing 250 kg presses on each inhabitant of the planet. The area of ​​the palm of an adult, on average, is 77 cm 2. That is, in accordance with physical laws, each of us holds 77 kg of air in the palm of our hand! This is equivalent to the fact that we constantly carry 5 pound weights in each hand. In real life, even a weightlifter cannot do this, however, each of us can easily cope with such a load, because atmospheric pressure presses from both sides, both outside the human body and from the inside, that is, the difference is ultimately equal to zero.

The properties of air are such that it affects the human body in different ways. High in the mountains, due to lack of oxygen, visual hallucinations occur in people, and at great depths, the combination of oxygen and nitrogen into a special mixture - “laughing gas” can create a feeling of euphoria and a feeling of weightlessness.

Knowing these physical quantities, it is possible to calculate the mass of the Earth's atmosphere - the amount of air that is held in near-Earth space by gravity. The upper boundary of the atmosphere ends at a height of 118 km, that is, knowing the weight of m 3 of air, you can divide the entire borrowed surface into air columns, with a base of 1x1m, and add up the resulting mass of such columns. Ultimately, it will be equal to 5.3 * 10 to the fifteenth degree of tons. The weight of the planet's air armor is quite large, but even it is only one millionth of the total mass of the globe. The Earth's atmosphere serves as a kind of buffer that keeps the Earth from unpleasant cosmic surprises. From solar storms alone that reach the surface of the planet, the atmosphere loses up to 100 thousand tons of its mass per year! Such an invisible and reliable shield is air.

How much does a liter of air weigh?

A person does not notice that he is constantly surrounded by transparent and almost invisible air. Is it possible to see this intangible element of the atmosphere? Clearly, the movement of air masses is broadcast daily on a television screen - a warm or cold front brings long-awaited warming or heavy snowfall.

What else do we know about air? Probably, the fact that it is vital for all living beings living on the planet. Every day a person inhales and exhales about 20 kg of air, a quarter of which is consumed by the brain.

The weight of air can be measured in different physical quantities, including liters. The weight of one liter of air will be equal to 1.2930 grams, at a pressure of 760 mm Hg. column and a temperature of 0°C. In addition to the usual gaseous state, air can also occur in liquid form. For the transition of a substance into this state of aggregation, the impact of enormous pressure and very low temperatures will be required. Astronomers suggest that there are planets whose surface is completely covered with liquid air.

The sources of oxygen necessary for human existence are the Amazonian forests, which produce up to 20% of this important element on the entire planet.

Forests are truly the “green” lungs of the planet, without which human existence is simply impossible. Therefore, living indoor plants in an apartment are not just an interior item, they purify the air in the room, the pollution of which is ten times higher than on the street.

Clean air has long become a shortage in megacities, the pollution of the atmosphere is so great that people are ready to buy clean air. For the first time, “air sellers” appeared in Japan. They produced and sold clean air in cans, and any Tokyo resident could open a can of clean air for dinner and enjoy its freshest aroma.

Air purity has a significant impact not only on human health, but also on animals. In polluted areas of equatorial waters, near populated areas, dozens of dolphins are dying. The reason for the death of mammals is a polluted atmosphere; in the autopsy of animals, the lungs of dolphins resemble the lungs of miners clogged with coal dust. The inhabitants of Antarctica are also very sensitive to air pollution - penguins, if the air contains a large amount of harmful impurities, they begin to breathe heavily and intermittently.

For a person, air cleanliness is also very important, so after working in the office, doctors recommend taking daily one-hour walks in the park, forest, and outside the city. After such "air" therapy, the body's vitality is restored and well-being improves significantly. The recipe for this free and effective medicine has been known since ancient times; many scientists and rulers considered daily walks in the fresh air to be a mandatory ritual.

For a modern urban dweller, air treatment is very relevant: a small portion of life-giving air, the weight of which is 1-2 kg, is a panacea for many modern ailments!

Anna Oreshkina
Summary of the lesson "Does air have weight"

Target: the formation of a holistic perception of the world, the development of interest in the research and cognitive activities of children.

Tasks:

Contribute to the enrichment and consolidation of children's knowledge about the properties air, expanding children's understanding of the significance air in human life, animals, plants; to develop in children the ability to establish causal relationships on the basis of an elementary experiment and draw conclusions; develop interest in research activities.

Lesson progress:

caregiver: Let's say hello to everyone.

(Communication game)

Let's stand next to each other

Say "Hello!" each other.

We are not too lazy to say hello:

Everyone "Hey!" And "Good afternoon!"

If everyone smiles -

Good morning will begin.

GOOD MORNING!

caregiver: Guys, tell me what surrounds us? Children: Houses, trees, birds, animals.

caregiver: Correctly!

caregiver: Guys, today we will learn something very interesting. We have a new assignment, it's in this beautiful box. Do you want to know what's inside her? (opens the box, it's empty)

Children: The box is empty, there is nothing in it.

caregiver: I do not agree with you, it is not empty, there is something in it, but what, you will know if you guess riddle:

Passes through the nose to the chest

And the reverse is on its way.

He's invisible, but still

We cannot live without it.

We need it to breathe

To inflate the balloon.

With us every hour

But he is invisible to us!

Children: Air!

caregiver: That's right, it's air!

air man: Oh, help, save, I'm flying!

caregiver: Who is that screaming?

(Flies into the room Air man - made of blue balloons).

caregiver: Hello, air man! How did you get to us?

air man: Hello guys! I was walking, but suddenly the wind picked me up and carried me, carried me and brought me to your kindergarten. How interesting are you here! What are you doing here? May I stay?

caregiver: Of course, stay. Today we are talking with the guys about air. air man: ABOUT air? What is air? I heard something about him, and never met him. Maybe it doesn't exist at all?

caregiver: Wait a minute, air man, I know that the air around us.

air man: I don't see anything. Where is he? Where did he hide?

caregiver: He didn't hide anywhere. Guys, let's prove To the air man that there really is air. Stay with us, air man and you will understand everything!

air man: Okay guys! I will stay!

caregiver: Guys, today we will talk about air like real scientists. Scientists work in a room with a lot of instruments for experiments, but what is the name of this room?

Children: Laboratory.

caregiver: Certain rules must be observed in the laboratory. Which? Children: Observe silence, do not interrupt each other, do not interfere with each other, work quietly, carefully, carefully.

caregiver: Let's go to our laboratory, conduct experiments (walk in a circle, then go to the tables).

To become a friend of nature

Know all her secrets

Unravel all mysteries

Learn to observe

Let's develop together

Quality is care

And it will help you to know

Our observation.

caregiver: So we found ourselves in a scientific laboratory. And for greater mystery, I hid all the devices in boxes.

We start experiments

It's interesting here

Try to understand everything

Much to know here

caregiver: Guys, do you know that a person can live without food - 30 days, without water - 15 days, and without air can't live even 5 minutes. Let's check.

Experiment "DELAY AIR»

caregiver: Let's take a deep breath air, hold your nose with your hand and "let's dive", and as soon as the air will run out, then "surface" (checks with an hourglass)

Conclusion: man cannot live without air.

Experiment "THE WEIGHT AIR»

(On the table laid out items: rubber toy, piece of rubber). caregiver: Let's put a piece of rubber and a rubber toy on the scale. What

heavier? That's right, a rubber toy. caregiver: Take a piece of rubber and put it in water. What happened to him? (he drowned). Now let's put a rubber toy into the water. What happened to her? (She doesn't drown). Why? Is the toy heavier than a piece of rubber? What's inside the toy? (Air)

Conclusion: air has weight but it is lighter than water.

Experiment « Does air have weight?»

caregiver: Guys, all objects around us have weight. How do you think, does air have weight? (answers)

We will check this now.

caregiver: For the next experiment, take two identical air balls and put them on the scales.

What do we see? (pans of scales are motionless)

Now put an inflated balloon on one bowl. What did you notice? Why? (answers)

Conclusion: Air has weight.

caregiver: So, we did a lot of experiments today. Tell me, did you like experimenting? (children's answers). What experience did you find most interesting? (children's answers). What did you learn new today? (children's answers).

caregiver: Oh, guys, hear, it's calling us air man?

air man: Guys, tell me, did I understand everything correctly or not?

caregiver A: We'll check it out now. I suggest you take 2 circles from the table. One red and one green. Instead of answering statements air little man you will show mugs. If you agree, raise the green circle, if you disagree, raise the red one. Let's try. Be careful!

Air surrounds us on all sides.

The air can be heard.

The air is transparent so we don't see it.

Clean the air is odorless, but can convey the smell of objects.

A person can live without air.

Wind is movement air. Air is heavier than water.

air man: Well done boys! I want to give you an item as a gift air. This balloon!

Children: Thanks!

Appendix

poem about air

He is a transparent invisible

Light and colorless gas.

He envelops us with a weightless scarf.

He is thick, fragrant in the forest,

Like a healing potion.

It smells of resinous freshness,

Smells like oak and pine.

In summer it is warm

It blows cold in winter.

When the frost lay on the glass

Lush white fringe.

We don't notice it

We don't talk about him.

We just breathe it in

We do need him.

MESSAGE ABOUT AIR

Air is an amazing shell around our Earth. If it wasn't air, all living things died in the scorching rays of the Sun during the day, and at night from the cold. Wind is movement air. He distills the cold air to the south, warm to the north, disperses clouds or collects them into rain clouds. Without air The earth would be a dead desert. Not in space air, so astronauts stock up air from earth. Air necessary for all creatures on Earth in order to breathe and live. We inhale the air is clean, and exhale - bad. And plants, on the contrary, inhale the bad leaves, and exhale the good. They cleanse air. The wind helps plants: blows dust from leaves, spreads seeds of plants throughout the Earth. Air- this is inanimate nature, but it is closely related to living nature.

Literature:

1. Tugusheva G.P., Experimental activity of children of middle and senior preschool age.

2. Dybina O. V. Unexplored nearby: Entertaining experiences and experiments for preschoolers. - M.: TC Sphere, 2005.

3. Dybina O. V. The child and the world around. Program and methodical recommendations. - M.: Mosaic-Synthesis, 2006

4. Zenina T. Ecological actions in work with preschoolers. // Preschool education. - 2002. - No. 7. - p. eighteen.

Municipal Autonomous Preschool Educational Institution

General developmental type kindergarten No. 12

municipality

Novorossiysk

Abstract in the preparatory group

On the topic: « Does air have weight»

Prepared and conducted:

A. V. Oreshkina

Novorossiysk 2017