Does air have mass? How much does air weigh. Determining the weight of air under given conditions
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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Does air have weight? Do not rush to say "yes" or "no", think.
Let's do this experiment.
Let's take a scale, such as shown in Figure 42. Put a children's balloon on the left scale pan, and pour sand in small portions on the right until balance is reached. Let's fill the balloon with air. We tie it up so that the air does not come out, and put it on the scales. The balance was disturbed - a cup with an inflated ball outweighed. So air has weight.
Rice. 42. This experience proves that air has weight
Air weight
By weighing the air, scientists found that it is very light. Its 1 cubic meter (abbreviated as 1 m 3: 1 m wide, 1 m long and 1 m high) weighs 1290 g. It should be remembered that air has such a weight only at the surface of the Earth. If air is weighed at different distances from the earth, then the weight of 1 m3 of air will decrease with height. The farther from the surface of the Earth, the more rarefied the air, less dense, and therefore weighs less.
Air pressure
Since the thickness of the atmosphere is more than 1000 km, the air exerts significant pressure on the earth's surface: it presses on 1 cm 2 of the Earth's surface with a force of 1 kg. Let us calculate what air pressure a person experiences (the surface of his body is on average 1.5 m 2, or 15 thousand cm 2).
It turns out that 15 tons of air presses on a person! Such a huge pressure, it would seem, he will not withstand. However, the person does not feel it. This is explained by the fact that blood, other liquids and gases in the body are compressed to the same pressure and, acting from the inside, balance the external pressure.
Air exerts pressure on all objects on the surface of the Earth.
To verify this, let's do an experiment.
We put a thin rail on the surface of the table so that half of it protrudes beyond the edge of the table. We cover the rail with a sheet of paper the size of a newspaper (you can use the newspaper itself). The paper should lie flat on the table surface. With a sharp blow of the hand on the rail, we will try to throw the paper off the table. However, the rail broke - the paper remained lying on the table. This is due to the fact that air presses on the paper from almost one side, since it fits snugly against the surface of the table.
Rice. 43. Experience proving that air exerts pressure on all objects on Earth. Even a strong blow to the ruler could not lift the newspaper
Air presses on all surrounding objects from all sides.
Back in 1654, the mayor of Magdeburg, Otto von Guericke, decided to show the townspeople the power of air pressure. For the experiment, two metal hemispheres were made (they were later called "Magdeburg"). Tightly adjacent to each other, they formed a hollow ball. In one of the hemispheres there was a hole for pumping out air, which was then tightly closed so that air could not enter the ball. In the experiment, two eights of horses harnessed to teams were used. Each harness was connected to the hemisphere through a strong hook. After the air was pumped out of the ball, collected from the hemispheres, the horses, on command, pulled the hemispheres in different directions in order to tear them apart. But the ball only swayed and remained unharmed. When air was let inside the ball, the hemispheres disintegrated themselves (Fig. 44).
Rice. 44. Experience with the Magdeburg hemispheres
Experience 7. Air is lighter than water.
Experience 6. The more air in the ball, the higher it jumps.
Experience 5. Air pushes objects.
Experience 4. We lock the air into a balloon.
Experience 3. Storm in a glass.
Children are invited to dip a straw into a glass of water and blow into it. What happens? (It turns out a storm in a teacup).
Children are invited to think, where can you find a lot of air at once? (In balloons). How do we inflate balloons? (Air) The teacher invites the children to inflate the balloons and explains: we seem to catch air and lock it in a balloon. If the balloon is inflated too much, it may burst. Why? All the air won't fit. So the main thing is not to overdo it. (invites children to play with balls).
After the game, you can invite the children to release the air from one balloon. Does it have sound? It is suggested that children put their palm under a stream of air. What do they feel? It draws the attention of children: if the air comes out of the balloon very quickly, it seems to push the balloon, and it moves forward. If you release such a ball, it will move until all the air comes out of it.
The teacher is interested in the children in which toy they are familiar with has a lot of air. This toy is round, can jump, roll, throw. But if a hole appears in it, even a very small one, then the air will come out of it and it will not be able to jump. (Children's answers are heard, balls are distributed). Children are invited to knock on the floor first with a deflated ball, then with a regular one. Is there a difference? What is the reason that one ball bounces off the floor easily, while the other barely bounces?
Conclusion: the more air in the ball, the better it jumps.
Children are encouraged to "drown" toys filled with air, including lifebuoys. Why don't they drown?
Conclusion: Air is lighter than water.
Let's try to weigh the air. Take a stick about 60 cm long. In its middle, fasten a rope, to both ends of which tie two identical balloons. Hang the stick on the string. The stick hangs in a horizontal position. Invite the children to think about what would happen if you pierced one of the balloons with a sharp object. Poke a needle into one of the inflated balloons. Air will come out of the balloon, and the end of the stick to which it is tied will rise up. Why? The balloon without air became lighter. What happens when we pierce the second ball too? Check it out in practice. You will regain your balance. Balloons without air weigh the same as inflated ones.
Experience 9. Warm air at the top, cold at the bottom.
For its implementation, two candles are needed. It is best to conduct research in cool or cold weather. Open the door to the street. Light the candles. Hold one candle at the bottom and the other at the top of the gap. Let the children determine where the flame of the candles leans (the flame of the lower one will be directed into the room, the upper flame will be directed outward). Why is this happening? We have warm air in the room. He travels easily, loves to fly. In a room, such air rises and escapes through a crack at the top. He wants to get out as soon as possible and walk free.
And the cold air is creeping in from the street. He is cold and wants to warm up. Cold air is heavy, clumsy (it's frozen!), so it prefers to stay close to the ground. From where will he enter our room - from above or below? This means that at the top of the door gap the flame of the candle is "bent" by warm air (after all, it runs away from the room, flies into the street), and at the bottom it is cold (it crawls towards us).
Conclusion: It turns out that one air, warm, moves above, and towards it, below, creeps "another", cold. Where warm and cold air move and meet, wind appears. Wind is the movement of air.
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: O 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. What 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 is 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 near: 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
Svetlana Chebysheva
Experience number 1. "Where is the air hiding?"
Equipment: cellophane bags, toothpicks.
Tell me, can you see the air around us? (no, we don't see)
So what is air? (invisible).
Let's catch some air.
Take plastic bags from the table and try to catch air.
Roll up the packages.
What happened to the packages? (they puffed up, took shape)
Try squeezing the package. Why doesn't it work? (there is air inside)
Where can this property of air be used? (inflatable mattress, life buoy).
Let's conclude: Air has no form, it takes the form of the object into which it enters.
Now look at your hand through the bag. Do you see a hand? (we see).
So what is air? (it is transparent, colorless, invisible).
Let's check, is there really air inside?
Take a sharp stick and carefully pierce the bag. Bring it to your face and press it with your hands.
What do you feel? (hiss).
This is how air comes out. We don't see it, but we feel it.
What can be concluded now? Air cannot be seen, but it can be felt.
Conclusion: Air is transparent, invisible, colorless, without form.
Experience number 2. "How to see the air?"
Equipment: straws for a cocktail, glasses with water.
Blow through the tube onto your palm.
What did the palm feel? (air movement - breeze).
We breathe air through the mouth or through the nose, and then we exhale it.
Can we see the air we breathe?
Let's try. Immerse the tube in a glass of water and blow.
Bubbles appeared on the water.
Where did the bubbles come from? (This is the air we exhaled).
Where do the bubbles float - rise up or sink to the bottom?
(Air bubbles rise up).
Because air is light, it is lighter than water. When all the air is out, there will be no bubbles.
Conclusion: Air is lighter than water.
Experience number 3. "Air is invisible"
Equipment: a large transparent container with water, a glass, a napkin.
At the bottom of the glass, you need to fix a paper napkin. Turn the glass upside down and slowly lower it into a container of water.
To draw the children's attention to the fact that the glass must be held very evenly. They took the glass out of the water and touched the napkin, it was dry.
What happens? Does water get into the glass? Why not?
This proves that there was air in the glass, which kept the water out of the glass. And since there is no water, it means that she cannot wet the napkin.
The children are invited to lower the glass into the jar of water again, but now it is proposed to hold the glass not straight, but slightly tilted.
What appears in the water? (visible air bubbles).
Where did they come from? Air leaves the glass and water takes its place.
Conclusion: The air is transparent, invisible.
Experience number 4. "Air Movement"
Equipment: Fans made from colored paper in advance.
Guys, can we feel the movement of air? What about seeing?
When walking, we often observe the movement of air. (trees sway, clouds run, turntable spins, steam from mouth).
Can we feel the movement of air in the room? How? (fan).
We cannot see the air, but we can feel it.
Take the fans and wave them in the face.
What do you feel? (Feel the air moving).
Conclusion: The air is moving.
Experience number 5. "Does air have weight?"
Equipment: two equally inflated balloons, a toothpick, scales ( can be replaced with a stick about 60 cm long. Fasten a rope in the middle, and balloons at the ends).
Invite the children to think about what would happen if you pierced one of the balloons with a sharp object.
Poke one of the inflated balloons with a toothpick.
Air will come out of the balloon, and the end to which it is tied will rise up. Why? (The balloon without air has become lighter).
What happens when we pierce the second ball too?
Poke a second ball with a toothpick.
You will regain your balance. Balloons without air weigh the same as inflated ones.
Conclusion: Air has weight.
