WHAT CAN AIR
Test 1
He can, for example, flip a coin! Place a small coin on the table and throw it into your hand with a push of air. To do this, holding your hand behind the coin with a shield, blow sharply on the table. Only not in the place where the coin lies, but at a distance of 4-5 cm in front of it.
The air compressed by your breath will penetrate under the coin and throw it straight into your handful.
A few tests - and you will learn how to take a coin from the table without touching it with your hand!
Test 2
If you have a narrow tapered glass, you can make another fun coin experience. Put a penny on the bottom of the glass, and a penny on top. It will lie horizontally like a lid, although it does not reach the edge of the glass.
Now blow sharply on the edge of the nickel.
It will stand on its edge, and a penny will be thrown out with compressed air. After that, the penny will fall into place. So the invisible person helped you to get a penny from the bottom of the glass, without touching either it or the penny lying on top.
Test 3
A similar experience can be done with egg cups. Put two such glasses side by side and in the one closest to you, put an egg.
In case of failure, take a tough egg. And now blow hard and sharply into the place indicated by the arrow in the figure, just to the very edge of the glass.
The egg will jump and "change" into an empty glass!
The invisible air slipped between the edge of the glass and the egg, burst into the glass, so much so that the egg jumped up!
For some, this experience does not work out - "lacks the spirit." But if, instead of a tough egg, you take an empty, blown shell, it will work out for sure!
HEAVY AIR
Take a wide wooden ruler (which you do not mind). Balance it at the edge of the table so that the ruler falls down with the slightest pressure on the free end. Now spread the newspaper on the table on top of the ruler. Spread it out carefully, smooth it out with your hands, smooth out all the folds.
Previously, the ruler could be knocked over with your finger. Now the newspaper has been added, but does it weigh much? Come on, bolder: stand on the side of the ruler and hit the end with your fist!
Even his fist is sick, and the ruler lies as if nailed in by nails. Well, now we'll show her how to resist! Take a stick and hit it with full swing. Bang! The ruler is in half, and the newspaper lies to itself as if nothing had happened.
Why was the newspaper so heavy?
Yes, because the air presses on her from above. 1 kg for every square centimeter. And oh, how many square centimeters the newspaper has! Well, count what area it is? Approximately 60 x 42 \u003d 2520 cm2. This means that the air presses on her with a force of two and a half thousand kilograms, two and a half tons!
Lift the newspaper slowly - the air will penetrate under it and press from below with the same exact force. But try to tear it off the table at once, and you've already seen what happens. The air does not have time to get under the newspaper - and the ruler breaks in half!
SCHOOL RUBBER SUCKER
Of the three items named in the title, the octopus is the least experimental. Firstly, it is difficult to get it, and secondly, jokes with the octopus are bad. How it grabs with its terrible tentacles, how it sucks with suckers - you can't tear it off!
Zoologists say that the octopus has a cup-shaped suction cup with a ring muscle. The octopus strains the muscle - the cup contracts, becomes narrower. And then, when this cup is pressed against the prey, the muscle relaxes.
Look how interesting: in order to hold on to its prey, the octopus does not strain its muscles, but relaxes them! And all the same, the suckers stick. Like a radish on a plate!
Experience
You and I had to give up experiments with a live octopus. But we will still make one suction cup - an artificial suction cup, from a school rubber band.
Take a soft elastic band and gouge a groove in the middle of one side. This will be the suction cup. Well, we use your muscles. After all, they are only needed to squeeze the suction cup first, and then they still relax, so that the hand can be removed.
Squeeze the elastic to make the cup smaller and press it against the plate. Just wet it first: the gum is not a radish, it has no juice of its own. By the way, the octopus also "works" with wet suckers.
Did you press the rubber band?
Now let go, she sucked securely.
There are also soap dishes with rubber suction cups. They stick to the tiled bathroom wall. They, too, must first be moistened, and then pressed against the wall and released. Hold on!
Well, now about the fly!
Tell me, have you ever thought about how she walks on the wall and even on the ceiling?
There is even such a riddle: "What's upside down above us?" Maybe a fly has a claw at the ends of its legs? Hooks with which it clings to the unevenness of the walls and ceiling? But she walks on the window pane completely freely, and on the mirror. There, too, the fly has nothing to catch. It turns out that the fly also has suckers on its legs.
So affirm after that that there is nothing in common between a fly and an octopus.
HOW TO EMPTY A GLASS?
The glass and bottle are filled with water. You need to empty the glass with the bottle without emptying it.
Poke two holes in the bottle cork and poke two straws through them, one equal in length to the height of the glass, the other twice as long. Then seal one end of the smaller straw with breadcrumb and plug the bottle so that the open ends of the straws enter the bottle.
Now, if you turn the bottle over, water will start flowing out of the large straw. Tip the bottle over a glass of water so that the small straw touches the bottom of the glass, and cut off the end sealed with bread crumb with scissors. Water flows out of the large straw until the glass is empty. Why?
This is explained as follows: the straws act as a siphon. The void in the bottle formed by the flowing out water is immediately filled with water from the glass, which is driven into the bottle by the air pressure on the surface of the water in the glass.
IntroductionWe hear about atmospheric pressure almost every day, for example, when we hear a weather forecast or a conversation between two grandmothers about pressure and headache... The atmosphere surrounds us everywhere and presses with its weight, but we do not feel this pressure in any way. How can you prove the existence of atmospheric pressure?
Hypothesis : if the atmosphere puts pressure on us and the bodies around us, then it can be detected empirically.purpose : experimentally prove the existence of atmospheric pressure.Tasks :1. Select and conduct experiments proving the existence of atmospheric pressure.
2. Show the practical application of atmospheric pressure in everyday life, technology, nature.
An object : Atmosphere pressure.Thing : experiments proving the existence of atmospheric pressure.Methods research: analysis of literature and materials on the Internet, observation, physical experiment, analysis and generalization of the results.Chapter 1 Understanding Atmospheric Pressure §1 From the history of the discovery of atmospheric pressureFor the first time atmospheric pressure was measured by the Italian scientist, mathematician and physicist Evangelisto Torricelli back in 1644. He took a glass tube 1 meter long, sealed at one end, filled it completely with mercury and turned it over, dipping the open end into a cup of mercury. To the surprise of others, only a small portion of the mercury spilled out of the tube. A 76 cm (760 mm) high column of mercury remained in the tube. Torricelli argued that the column of mercury is held back by atmospheric pressure. It was he who first came up with this idea. Torricelli called his device a mercury barometer and suggested measuring atmospheric pressure in millimeters of mercury (Fig. 1).
Figure: 1 Torricelli mercury barometer Fig. 2 Water barometer
Since then, the name of the barometer has appeared (from the Greek.
baros - severity,metreo - measuring).The experiments on measuring atmospheric pressure were carried out by the French scientist Blaise Pascal, after whom the unit of pressure is named. In 1646 he built a water barometer to measure atmospheric pressure. To measure atmospheric pressure of 760 mm Hg, the height of the water column in this barometer reached more than 10 meters, which, of course, is very inconvenient (Fig. 2).
Modern barometers are available to every man in the street. Figure 3 shows a modern barometer - aneroid (translated from Greek -
aneroid ). The barometer is so called because it does not contain mercury.
Fig. 3 Barometer - aneroid
Many scientists tried to prove the existence of atmospheric pressure, conducted experiments. A 7th grade physics textbook describes an experiment proving the existence of atmospheric pressure. In 1654 an experiment was carried out with the "Magdeburg hemispheres". The air was evacuated from the metal hemispheres tightly pressed to each other. Atmospheric pressure compressed them so strongly from the outside that even 16 (eight pairs) horses, pulling the hemispheres in different directions, could not separate the hemispheres again (Fig. 4). This experiment was carried out by the German physicist, burgomaster of the city of Magdeburg Otto von Guericke.
Now in Germany, monuments to the famous "Magdeburg hemispheres" can be found at every step (Fig. 5).
Fig.4 Experiment with hemispheres Fig.5 "Magdeburg hemispheres"
§2 Features of atmospheric pressureWhat is the mechanism of atmospheric pressure occurrence? We found the answer to this question in textbooks of natural history, physics, on the Internet.
The air shell surrounding the Earth is called the atmosphere (from the Greek
atmos - steam, air,sphere - ball) .The atmosphere extends to a height of several thousand kilometers and looks like a multi-storey building (Fig. 6). As a result of the attraction of the Earth, the upper layers of the atmosphere press their weight on the lower layers. The air layer adjacent directly to the Earth is compressed the most and, according to Pascal's law, transfers pressure in all directions to everything on and near the Earth.
Fig. 6 The structure of the Earth's atmosphere.
Observations of meteorologists show that atmospheric pressure in areas lying above sea level is on average 760 mm Hg, this pressure is called
normal atmospheric pressure ... Air density decreases with altitude, which leads to a decrease in pressure. At the top of the mountain, atmospheric pressure is less than at its foot. With small rises, on average, for every 10.5 m lift, the pressure decreases by 1 mm Hg or 1.33 hPa.The existence of atmospheric pressure can explain many of the phenomena that we encounter in life. For example, I learned from a 7th grade physics textbook that as a result of atmospheric pressure, a force equal to 10N acts on every square centimeter of our body and any object, but the body does not collapse under the influence of such pressure. This is due to the fact that it is filled with air inside, the pressure of which is equal to the pressure of the outside air. When we breathe in air, we increase the volume of the chest, while the air pressure inside the lungs decreases and the atmospheric pressure pushes in a portion of air there. When exhaling, the opposite happens.
How do we drink?
The inhalation of fluid into the mouth causes the chest to expand and the air in both the lungs and the mouth is reduced. The pressure inside the mouth decreases. The increased, in comparison with the internal external atmospheric pressure "drives" part of the liquid there. This is how the human body uses atmospheric pressure.The principles of operation of many devices are based on the phenomenon of atmospheric pressure. One of these is the piston fluid pump. The pump is shown schematically in Figure 7 It consists of a cylinder, inside which a piston tightly adjoining the walls goes up and down. When the piston moves up, water under the influence of atmospheric pressure rises up (into the void).
A medical syringe, which has found wide application in medicine, works on the same principle.It is curious that back in 1648, the French philosopher, mathematician and physicist Blaise Pascal, studying the characteristics of the behavior of a fluid under pressure, invented a syringe - a funny construction of a press and a needle. The real syringe appeared only in 1853. It is curious that two people who worked independently of each other designed the injection machine at once: the Scotsman Alexander Wood (Wood) and the Frenchman Charles Gabriel Pravaz (Pravaz). And the name "spritze", which means "to inject, to spray", was invented by the Germans.
Fig. 7 Pump Fig. 8 Hydraulic press and fountain
The action of atmospheric pressure explains the principle of operation of a hydraulic press, jack, hydraulic brake, fountain, air brake and many technical devices (Fig. 8).
Differences in atmospheric pressure affect the weather.
With a decrease in atmospheric pressure, air humidity rises, precipitation and an increase in air temperature are possible. When atmospheric pressure rises, the weather becomes clear and does not have sudden changes in humidity and temperatures.In order for a person to be comfortable, the atmospheric pressure should be 750 mm. rt. pillar.If the atmospheric pressure deviates, even by 10 mm, in one direction or another, the person does not feel comfortable and this can affect his health.
As a result of theoretical research, we have established that atmospheric pressure significantly affects human life.
Chapter 2 Experiments Confirming the Existence of Atmospheric Pressure Experience number 1 . The principle of operation of a medical syringe and pipette . Devices and materials : syringe, pipette, glass of tinted water.Experience progress : lower the syringe plunger down, then lower it into a glass of water and raise the plunger. The water will enter the syringe (Fig. 9). We press on the rubber band of the pipette, the liquid enters the glass tube.Explaining experience : When the plunger is lowered, air is released from the syringe and the air pressure in it decreases. Outside air, under the influence of atmospheric pressure, pushes liquid into the syringe. The pipette works according to the same principle (Fig. 10).
Fig. 9 Medical syringe Fig. 10 Pipette
Experience number 2. How to get a coin out of the water without getting your hands wet? Devices and materials : plate, candle on a stand, dry glass.Experience progress : put a coin on a plate, then pour some water, put a lighted candle. Cover the candle with a glass. The water ends up in the glass, and the plate is dry.Explaining experience : the candle burns and the air from under the glass is diluted, the air pressure there decreases. The atmospheric pressure outside drives the water under the glass.
Fig. 11 Coin experiment
Experience number 3. The glass is a sippy cup. Devices and materials : glass, water, sheet of paper.Experience progress : pour water into a glass and cover with paper on top. Turn the glass over. The sheet of paper does not fall, water does not spill from the glass.Explaining experience : the air presses from all sides and upwards too. Water acts on the leaf from above. The water pressure in the glass is equal to the outside air pressure.Experience number 4. How to put an egg in a bottle? Devices and materials : glass bottle with a wide neck, boiled egg, matches and candles for the cake.Experience progress : Peel the boiled egg from the shell, stick the candles into the egg and light them. We will bring the bottle from above and insert the egg into it like a cork. The egg will be sucked into the bottle.Explanation of experience: the fire displaces oxygen from the bottle, the air pressure inside the bottle has decreased. Outside, the air pressure remains the same and pushes the egg into the bottle (Fig. 12).
Figure: 12 Egg experiment Fig. 13 Bottle experiment
Experiment # 5. A flattened bottle. Devices and materials : kettle with hot water, empty plastic bottle.Experience progress : rinse the bottle with hot water. Drain the water and quickly close the bottle. The bottle will flatten.Explaining experience : hot water heated the air in the bottle, the air expanded. When the bottle was closed with a cork, the air cooled down. At the same time, the pressure decreased. Outside, atmospheric air squeezed the bottle (Fig. 13).Experience number 6. A glass of water and a sheet of paper.
Devices and materials : glass, water and a sheet of paper.
Experience progress : pour water into a glass (but incomplete), cover with a sheet of paper and turn over. The leaf will not fall off the glass.
Explaining experience : a sheet of paper holds atmospheric pressure, which from the outside acts with greater force than the weight of water in a glass. (Figure 14)
Figure: 14 glass experience
Experience number 7. Otto von Guericke at home.
Devices and materials : 2 glasses, a ring of a sheet of paper with a diameter of a glass soaked in water, a candle stub, matches.
Experience progress : put a lighted candle in one glass, put a paper ring moistened with water on top and cover with a second glass and press lightly. The candle goes out, raise the top glass and notice that the second glass is pressed against the top one.
Explaining experience : the air has expanded from heating and part of it has escaped. The less air remains inside, the more they are compressed from the outside by atmospheric pressure, which remains constant. Penetration of air, interferes with a paper ring moistened with water
Fig. 15 Magderburg hemispheres at home.
Chapter 3. Practical use of atmospheric pressure.
1.How do we drink? We put a glass or spoon with liquid to our mouth and "suck" their contents into ourselves. Why, in fact, does the liquid rush into our mouth? What fascinates her? The reason is this: when drinking, we expand the chest and thus thin the air in the mouth; under the pressure of the outside air, the liquid rushes towards us into the space where the pressure is less, and thus penetrates into our mouth.
So, strictly speaking, we drink not only with our mouth, but also with our lungs; because the expansion of the lungs is the reason that the liquid rushes into our mouth.
2. Atmospheric pressure in wildlife... Flies and tree frogs can stick to the window pane thanks to the tiny suction cups that create vacuum and atmospheric
the pressure keeps the suction cup on the glass. Sticky fish have a suction surface consisting of folds that form deep "pockets". 
When you try to tear off the suction cup from the surface to which it is adhered, the depth of the pockets increases, the pressure in them decreases, and then the external pressure presses the suction cup even more.
3.Automatic bird drinker consists of a bottle filled with water and tipped over in a trough so that the neck is slightly below the water level in the trough. Why isn't water pouring out of the bottle? Atmospheric pressure keeps the water in the bottle.
4. Piston liquid pump
water in the cylinder rises behind the piston under the influence of atmospheric pressure. This is the basis of the action of piston pumps. The pump is shown schematically in the figure. It consists of a cylinder, inside of which a piston 1, tightly fitting to the walls, moves up and down. In the lower part of the cylinder and in the piston itself, valves 2 are installed, opening only upward. When the piston moves up, water, under the influence of atmospheric pressure, enters the pipe, lifts the bottom valve and moves behind the piston. (see appendix Fig. 1). When the piston moves down, the water under the piston presses on the lower valve and it closes. At the same time, under the pressure of water, a valve inside the piston opens and water flows into the space under the piston. With the subsequent movement of the piston upwards, the water above it rises with it, which is poured into the pipe. At the same time, a new portion of water rises behind the piston, which, with the subsequent lowering of the piston, will be above it.
5.Liver it is a device for taking various liquids. Leaver is dipped into the liquid, then the upper hole is closed with a finger and removed from the liquid. When the top hole is opened, water begins to flow from the liver
6.
Aneroid barometer
Is an instrument for measuring atmospheric pressure based on a liquid-free design. The operation of the device is based on the measurement of elastic deformations caused by atmospheric pressure
a thin-walled metal vessel from which air is evacuated.
Props: a plastic bottle with a lid and a long glass tube with a diameter of 6-8 mm, open at both ends (it may well be replaced by a rubber or plastic tube).
Experience progress:
Make a hole in the bottle cap to fit the tube snugly.
In the bottle itself, closer to the bottom, make a small hole 1-2 mm.
Pour water into a bottle and screw on the cap and tube. The end of the tube must be above the level of the hole.
The jet from the hole flows out with constant speed, despite the decrease in the level of liquid in the vessel! The jet shape does not change! Only when the water drops to the lower level of the tube, the pressure does not start to decrease.
The water pressure can be changed by changing the immersion depth of the tube in the bottle.
Explanation:the pressure at the level of the hole is equal to the sum of atmospheric and hydrostatic pressures. It will remain so until the water level drops to the lower end of the tube.
Props: two plastic bottles with lids, a film case.
Experience progress:
Punch the same holes with a diameter of 6 - 8 mm in the bottle caps.
Cut the bottom off the film case.
Insert the threaded caps from both ends of the resulting cylinder.
Fill one bottle one-third with water.
Connect bottles with caps.
Place the bottles upright with the water bottle on top.
No water will flow out of the upper bottle!
This experiment repeats the experiment described in the literature with a funnel inserted into a bottle. Water is poured into the funnel from a glass, water does not flow out of it. The funnel experience is not always successful. requires a tight connection between the funnel and the bottle, as well as reducing the inner opening of the funnel. The proposed experience is reliable, it always turns out, the water does not pour out for months.
Explanation:on close observation, you will notice that a small portion of water has flowed out of the top bottle. Consequently, the air pressure in it became less than atmospheric, in the lower bottle - more than atmospheric. The increase in pressure in the lower bottle was sufficient to balance the hydrostatic pressure of the water in the upper bottle. The surface tension of water also plays a role.
Props:plastic bottle, hot water.
Experience progress:
Rinse the plastic bottle with hot tap water.
Close the bottle tightly.
Bytylka doubts. This is not shown in the film. We only see the result.
Explanation: the air in the bottle cools down to room temperature. The pressure inside the bottle drops and becomes less than atmospheric. The atmosphere squeezes the bottle from the sides. The plastic bottle is deformed. The air cools down so quickly that the entire experience takes about ten seconds.
The same effect can be obtained using a vacuum pump. Close the plastic bottle with a cap with a tube and connect it with a hose to a vacuum pump. After several strokes of pumping out, the bottle with a characteristic sound turns into a "cake". The shape of the bottle will be restored if it is pumped again with air.
Topic for research: a large number of plastic bottles of various sizes and shapes are produced. Examine if they deform equally. Explain the research result.
Props: rectangular cardboard of any size, newspaper, dynamometer (or rubber band), large paper clip, tape.
Experience progress:
In the center of the cardboard, use duct tape to vertically secure a large paper clip bent into a triangle.
Place the cardboard on the table, paperclip facing up, and on top of it, an unfolded newspaper. Rip through the newspaper where the paperclip is.
Attach a dynamometer to a paperclip and pull it sharply.
Use a dynamometer to measure the force that must be applied to tear the newspaper and cardboard off the table.
Measure the weight of the newspaper carton.
Compare the result.
The results are strikingly different. A sharp movement requires tens of times more strength!
Explanation:the force of atmospheric pressure acting on a newspaper is determined by the product of atmospheric pressure by the area of \u200b\u200bthe newspaper. This force is significantly greater than the weight of the cardboard along with the newspaper.
Municipal autonomous educational institution
"Average comprehensive school №16
syktyvkar city with in-depth study of individual subjects "
Proof of existence
atmospheric pressure
Toropov Ivan, 5 "v" class
Leader:
Toropova Irina Ivanovna,
Physics teacher
year 2013
- Introduction - page 2
- Material and method - page 3
3.3.1 Research results - page 4
3.2 Effect of atmospheric pressure - page 5
3.3 Experiments supporting existence
atmospheric pressure - page 6-8
3.4 Influence of atmospheric pressure on humans - page 8
3.5 The meaning of the atmosphere - page 9
- Conclusions - page 10
4.Literature-p. eleven
1. Introduction
The goal is to provide evidence of the existence of atmospheric pressure.
Tasks:
- Collect atmospheric pressure information
- Conduct experiments to confirm the existence of atmospheric pressure
- Determine the role of atmospheric pressure in human life.
- Analyze the results and information obtained.
2.Material and method
The research date is January - early March 2013.
Venue - school physics room
Description:
1.Find out what atmospheric pressure is
2 who first discovered the existence of atmospheric pressure
3.What experiments confirm the existence of atmospheric pressure
4. Find out the value of atmospheric pressure for everything living on Earth.
3.1 Research results
Atmosphere pressure - pressure of atmospheric air on objects in it and on the earth's surface
Atmospheric pressure is created by the gravitational attraction of air to the Earth
Evangelista Torricelli invented a device that consisted of a glass tube sealed on top and a vessel filled with mercury. Torricelli poured mercury into a glass tube, then turned it over. At first, some amount of mercury spilled out of the tube, but then the height of the column hardly changed.
He divided a glass tube 1 meter high into 1000 parts. What is 1 part? (1 mm). Therefore, atmospheric pressure is measured in millimeters of mercury. Since then, the normal pressure is considered to be 760 mm Hg.
3.2 EFFECT OF ATMOSPHERIC PRESSURE.
1.As a result of atmospheric pressure, a force equal to 10N acts on every square centimeter of our body and any object, but the body does not collapse under the influence of such pressure. This is due to the fact that it is filled with air inside, the pressure of which is equal to the pressure of the outside air.
When we inhale air, we increase the volume of the chest, while the air pressure inside the lungs decreases and the atmospheric pressure pushes in a portion of air there.
When exhaling, the opposite happens.
2. Many living organisms, for example worms, octopuses, fluke worms, leeches, houseflies, have suckers, with which they can stick, suck to any object. Leeches use suction cups to move along the bottom of the reservoir, octopuses - to grab prey. ... The suction cups increase in volume, so a rarefied space is formed inside them, and the external air pressure presses them against any object.
3. .. On earth surface atmospheric pressure varies from place to place and over time. Particularly important are the weather-defining non-periodic changes in atmospheric pressure associated with the emergence, development and destruction of slowly moving areas of high pressure (anticyclones) and relatively fast moving huge eddies (cyclones), in which reduced pressure prevails.
4. But fish feel fluctuations in atmospheric pressure much better
Fish, in order to reduce the effect of high pressure, should rise to higher layers of water. And vice versa - at low - to go deeper.
3.3 Experiences supporting
existence of atmospheric pressure
Experience number 1
(water in a syringe).
Devices and materials: syringe, glass with colored water ..
The course of the experiment: lower the syringe plunger down, then lower it into a glass of water and raise the plunger. The water will go into the syringe.
Explanation of the experience: when the piston is lowered, air comes out of the syringe and the air pressure in it decreases. Outside air pushes water into the syringe.
Experience number 2.
(dry plate)
Appliances and materials: plate, candle, dry glass.
The course of the experiment: pour some water into a plate, put a lighted candle. Cover the candle with a glass. The water ends up in the glass, and the plate is dry.
Explanation of the experiment: the fire pushes air out from under the glass, the air pressure decreases there. The atmospheric pressure outside drives the water under the glass.
Experience number 3.
(sippy glass).
Devices and materials: glass, water, sheet of paper.
The course of the experiment: pour water into a glass and cover it with paper on top. Turn the glass over. The sheet of paper does not fall.
Explanation of experience: the air presses from all sides and from the bottom up too. Water acts on the leaf from above. The water pressure in the glass is equal to the outside air pressure.
Experience number 4.
(egg in a bottle)
Appliances and materials: glass milk bottle, boiled egg, matches and candles for the cake.
The course of the experiment: insert candles into the egg and light them. Bring the bottle on top and insert the egg as a cork.
Explanation of the experience: the fire displaces oxygen from the bottle, the air pressure inside the bottle has decreased. outside the air pressure remains the same and pushes the egg into the bottle.
Experience number 5.
(flattened bottle)
Devices and materials:
Hot water kettle, empty plastic bottle.
Experience progress: rinse the bottle with hot water. Drain the water and quickly close the bottle. The bottle will flatten.
Explanation of the experiment: hot water heated the air in the bottle, the air expanded. When the bottle was closed with a cork, the air cooled down. At the same time, the pressure decreased. Outside, atmospheric air squeezed the bottle.
Experience number 6.
(mighty sucker).
Appliances and materials: soap dish with suction cup, blackboard, laptop.
The course of the experiment: press the soap dish with the suction cup to the board - the soap dish holds. Press the soap dish to the laptop - you can raise the device high enough. The suction cup holds.
Explanation of the experience: when we press the soap dish to the surface, air is squeezed out from under the suction cup, the pressure there decreases. The air outside continues to exert pressure. The suction cup holds on.
Experience number 7.
(medical bank)
Devices and materials: medical banks, alcohol
The course of the experiment: moisten cotton wool with alcohol and set it on fire. Warm up the jar from the inside and put it on the patient's back.
Explanation of the experiment: fire squeezes out oxygen from the can When the can is pressed against the back, the air pressure inside the can is small. Outside, normal air pressure. It pulls in the tissues of the back. The result is a bulge.
3. 4 Influence of atmospheric pressure on humans
Cardiovascular diseases:
,
- a sharp decrease or increase (by 8 degrees or more) in air temperature;
- sharp drops in atmospheric pressure (more than 6 mm Hg during the day);
-
(air temperature more than + 25 ° С) or strong (temperature below -20 ° C);
- air humidity above 80%;
- strong wind (8 m / s and more)
.
Respiratory diseases:
:
- the same drops in air temperature and pressure and strong wind;
- especially dangerous hot with high air humidity in summer and dank slush in winter.
3.5 Significance of the atmosphere
1. The atmosphere protects all life on Earth from the destructive effects of ultraviolet rays, from rapid heating by the sun's rays and cooling.
2. The atmosphere is a reliable protection of our planet from meteorites. If it were not for her, they would have rained down on the Earth. While meteorites fly through the atmosphere, they encounter air resistance, heat up and burn. This phenomenon can be observed in the night sky. It is called "star rain" or "shooting stars".
3. The atmosphere determines all life processes on Earth and has big influence on human life and economic activity.
4. A person uses the energy of moving air masses, for example, to obtain electrical energy, for this purpose wind power plants are built.
3.6 Conclusions.
- Collected information about atmospheric pressure.
- Experiments were carried out to confirm the existence of atmospheric pressure.
- Information has been found on the effect of atmospheric pressure on all bodies on Earth and on humans.
- Atmospheric pressure exists.
- It affects all objects on Earth and man.
Literature
1. Balashov M. M. About nature. M., Enlightenment, 1991
2. Physics evenings on Wed. school. Composition. Braverman E.M. M., Enlightenment, 1969
3. Vladimirov A. V. Stories about the atmosphere. M., Enlightenment, 1981
4. Halperstein L. Amusing Physics. M., Enlightenment, 1993
5. Gorev L.A. Entertaining experiments in physics. M., Enlightenment, 1985
7. Katz I. Biophysics in physics lessons. M., Enlightenment, 1988
9. Pokrovsky SF Observe and explore yourself. M., Education, 1966