The fact that the Earth is covered with an air shell called atmosphere, you learned in geography lessons, let's remember what you know about the atmosphere from the geography course? It is composed of gases. They completely fill the volume provided to them.
V the question arises: why air molecules in the atmosphere, moving continuously and randomly, do not fly away into space? What keeps them at the surface of the Earth? What is the power? Retains gravity! So the atmosphere has mass and weight?
Why doesn't the atmosphere “settle” on the Earth's surface? Because between the air molecules there are forces not only of attraction, but also of repulsion. In addition, to leave the Earth, they must have a speed of at least 11.2 km / s, this is the second cosmic speed. Most of the molecules have a speed of less than 11.2 km / s.
Experience 1. Take two rubber balls. One is inflated, the other is not. What's in an inflated balloon? We put both balls on the balance. An inflated ball on one bowl, deflated on the other. What do we see? (An inflated balloon is heavier).
We found out that the air, like any body on Earth, is affected by gravity, has mass, and, therefore, has weight.
Guys, stretch your arms out, palms up. What do you feel? Is it hard for you? But air presses on your palms, and the mass of this air is equal to the mass of a KAMAZ loaded with bricks. That is about 10 tons! Scientists have calculated that the air column presses on the area 1 cm 2 with such force as a weight in 1 kg 33 g.
Air mass in 1m³ of air: at sea level - 1 kg 293g; at an altitude of 12 km - 310 g; at an altitude of 40 km - 4g.
Why don't we feel this weight?
How is the pressure exerted on the lower air layer by the upper layer transmitted? Each layer of the atmosphere is under pressure from all the upper layers, and, therefore, the earth's surface and the bodies on it are under pressure from the entire thickness of the air, or, as they usually say, under atmospheric pressurenenie, and, according to Pascal's law, this pressure is transmitted equally in all directions.
What substance does the atmosphere consist of? Out of thin air? And what is he? Air - gas mixture: 78% - nitrogen, 21% - oxygen, 1% - other gases (carbon, water vapor, argon, hydrogen ...) ... We often forget that air has weight. Meanwhile, the air density at the Earth's surface at 0 ° C is 1.29 kg / m 3. That air does have weight was proved by Galileo. And Galileo's student Evangelista Torricelli suggested and was able to prove that air exerts pressure on all bodies on the surface of the Earth. This pressure is called atmospheric pressure.
Atmospheric pressure - the pressure exerted by the Earth's atmosphere on all objects on it.
This is modern theoretical knowledge, but how did you learn about atmospheric pressure in practice?
The assumptions about the existence of atmospheric pressure arose in the 17th century.
The experiments of the German physicist and burgomaster of Magdeburg, Otto von Guericke, were well known for its study. Somehow pumping air out of a thin-walled metal ball, Gericke suddenly saw this ball flatten. Reflecting on the cause of the accident, he realized that the flattening of the ball was caused by the pressure of the surrounding air.
To prove the existence of atmospheric pressure, he conceived and conducted such an experiment.
On May 8, 1654, in the German city of Regensburg, in a very solemn atmosphere, many nobility gathered, led by Emperor Ferdinand III. All of them witnessed an amazing spectacle: 16 horses struggled to separate 2 attached copper hemispheres, which had diameters of about a meter. What connected them? Nothing! - air. However, 8 horses pulling in one direction and 8 in the other could not separate the hemispheres. So the burgomaster of Magdeburg, Otto von Guericke, showed everyone that air is not nothing at all and that it presses with considerable force on all bodies. (2 assistants)
By the way, all people have "Magdeburg hemispheres" - these are the heads of the femurs, which are held in the pelvic joint by atmospheric pressure.
Now we will repeat the experiment with the Magdeburg Hemispheres and reveal its secret.
Experience 2. Let's take two glasses. We put a lit candle stub into one of the glasses. Cut a ring out of several layers of newsprint with a diameter slightly larger than the outer edge of the glass. After moistening the paper with water, place it on the top edge of the first glass. Carefully ( slowly) put an inverted second glass on this spacer and press it to the paper. The candle will soon go out. Now, grasping the top glass with our hand, raise it. We will see that the lower glass, as it were, stuck to the upper one and rose with it. Why did this happen? The fire heated the air contained in the lower glass, and, as we already know, the heated air expands and becomes lighter, so part of it came out of the glass. This means that when both glasses were tightly pressed against one another, there was less air in them than before the start of the experiment. The candle went out as soon as all the oxygen contained in the glasses was consumed. After the gases remaining inside the glass cooled down, a rarefied space arose there, and the atmospheric pressure outside remained unchanged, so it pressed the glasses tightly against one another, and when we lifted the upper one, the lower one rose with it. We see that the pressure of the atmosphere is great.
How to measure the pressure of the atmosphere?
It is impossible to calculate atmospheric pressure using the formula for calculating the pressure of a liquid column. Indeed, for this it is necessary to know the density and height of the liquid or gas column. But the atmosphere does not have a clear upper limit, and the density of atmospheric air decreases with increasing altitude. Therefore, Torricelli proposed a completely different way to find atmospheric pressure.
Torricelli took a glass tube about one meter long, sealed at one end, poured mercury into this tube and lowered the tube with its open end into a bowl of mercury. Some of the mercury poured into the bowl, but most of the mercury remained in the tube. From day to day, the level of mercury in the tube fluctuated slightly, sometimes dropping slightly, sometimes rising slightly.
The pressure of mercury at the level of its surface is created by the weight of the column of mercury in the tube, since there is no air in the upper part of the tube above the mercury (there is a vacuum, which is called the "Torricellian void"). Hence it follows that atmospheric pressure is equal to the pressure of the column of mercury in the tube. By measuring the height of the column of mercury, you can calculate the pressure that the mercury produces. It will be equal to atmospheric. If atmospheric pressure decreases, then the mercury column in the Torricelli tube decreases, and vice versa. Observing daily the change in the level of the column of mercury, Torricelli noticed that it could rise and fall. Torricelli also linked these changes to changes in the weather.
At present, the pressure of the atmosphere, equal to the pressure of a column of mercury with a height 760 mm at a temperature of 0 ° C, it is customary to call normal atmospheric pressure which corresponds to 101 325 Pa.
760 mmHg Art. =101 325 Pa 1 mm Hg. Art. =133.3 Pa
If you attach a vertical scale to the Torricelli tube, you get the simplest instrument for measuring atmospheric pressure - mercury barometer .
But using a mercury barometer is unsafe because mercury vapor is poisonous. Subsequently, other instruments for measuring atmospheric pressure were created, which you will become familiar with in the next lesson.
Atmospheric pressure close to normal is usually observed in areas at sea level. With increasing altitude (for example, in the mountains), the pressure decreases.
Torricelli's experiments interested many scientists - his contemporaries. When Pascal found out about them, he repeated them with different liquids (oil, wine and water).
Experience 3. If you make a hole in the cap of a water bottle, squeeze and release some of the water. What happens to the shape of the bottle? Why is it deformed? What needs to be done so that it straightens up and the water starts pouring out again intensively?( as a result of a puncture of the bottle, atmospheric air began to enter the bottle and press on the water, this is used in droppers when delivering medicines).
This method of changing the pressure in the bottle is used by housewives in cooking when separating the yolks from the whites. How?
Atmospheric pressure also explains the suction effect of the swamp or clay. When a person tries to pull a leg out of a swamp or clay, a vacuum is formed under it, and the atmospheric pressure does not change. The overweight of atmospheric pressure can reach 1000 N per leg of an adult.
Experience 4. How to get a coin with your hands from the bottom of a plate of water without getting it wet? It is necessary to put a piece of potato with matches stuck in it or a candle in a plate of water and light it. Cover with a glass on top. The combustion has stopped and the water has collected in the glass and the coin can be freely taken from the dry plate. What caused the water to collect under the glass?
We have observed interesting phenomena that are caused by the action of atmospheric pressure. Where have you seen such devices in life, the actions of which are based on the existence and change of atmospheric pressure?
Municipal budgetary educational institution "Uvarovskaya secondary school" of the Leninsky district of the Republic of Crimea
PLAN-CONSPECT
LESSONS IN PHYSICS
FOR 7 CLASS ON THE TOPIC:
"Atmosphere pressure"
Technologies: differentiated learning, health-preserving and information and communication, research.
Developed by: Shatilo Valentina Alexandrovna
Physics teacher
Lesson topic:"Atmosphere pressure".
Target: reveal the nature of atmospheric pressure, show by experiments and explain by examples of the existence of atmospheric pressure. Introduce Torricelli's experience. Expand causal relationships when explaining examples and experiments based on knowledge of atmospheric pressure. Pay attention to the fact that atmospheric pressure is a causal factor in the environment and predetermines the course of vital processes in living organisms. Continue to develop practical skills in solving problems. To contribute to the formation of such basic ideological ideas as the unity of nature and man. Develop logical thinking. To continue the formation of interest in the history of the development of the science of physics.
Lesson type: a lesson in the study of new educational material and primary consolidation.
Technology: interactive, research
Lesson structure
| 1. Organizational moment. | |
| 2. Actualization of students' knowledge. | |
| 3. Goal setting | |
| 4. Motivation for learning activities. | |
| 5. The stage of obtaining new knowledge. | |
| 6. Relaxation | |
| 7. Consolidation of educational material. | |
| 8. Summing up the lesson. | |
| 9. Reflection. | |
| 10. Homework. |
Demonstrations: 1. The existence of atmospheric pressure (glass of water, paper, medical syringe, pipette, liver, air balloon under vacuum).
2. Tables (Torricelli experiment, barometer).
3. Computer support for the lesson: presentation, video and virtual experiments.
During the classes
Epigraph:
"Physics is the science of understanding nature." Edward Rogers
Organizing time.
Checking the readiness of students for the lesson. Greetings.
Today we will give a lesson that will show all your knowledge and abilities. It will expand your horizons, teach you to apply the knowledge gained in life. You only need to be active and attentive during the lesson.
Teacher: Physics is the science of nature, I think you will agree with the statement of the English scientist Edward Rogers "Physics is the science of understanding nature." What does it mean? (With the help of the laws of physics, we explain the phenomena that occur in nature.)
During the lesson, each of you will receive grades for different types of activities, you will enter them in the assessment cards for the lesson.
| Assessment card for student work in the lesson students _____ class ___ Surname ___________________ First name ___________ | ||||||
| Blitz - poll (homework check) | "Virtual Experiments and Their Explanation" | For being active and giving correct answers while studying a new topic | To work in a group | Testing | Grade per lesson |
|
Updating basic knowledge.
Testing knowledge in the form of a frontal conversation and the game "Live Computer".
Blitz - poll
The bag should have wide straps, not narrow straps. Why?
If, when crossing the ice, a person fell through, then the rescuer should crawl towards him, and it is recommended to put boards or skis on the edge of the ice hole. Why
Why does fluid pressure build up?
(Because gravity is at work.)
What does the fluid pressure depend on?
(Depends on density and liquid column.)
How does the pressure of the liquid depend on the shape of the vessels?
(Does not depend on the shape of the vessels.)
In what units is pressure measured?
(in Pascals)
What is the formula for determining the pressure of the liquid on the bottom and walls of the vessels?
In what units are the quantities included in this formula measured?
(density ρ in kg / m, column height h in meters, g = 9.8 N / kg.)
Formulate Pascal's law.
(The pressure that acts on a liquid or gas is transmitted unchanged to every point of the liquid or gas.)
Testing
1. In what units is pressure measured?
A) N. B) Pa. B) m 2.
2. Than ……………. The support area, the ………… .. pressure.
A) more; smaller. B) more; more. B) less; smaller.
3. What statement is called Pascal's law?
A) The pressure exerted on a liquid or gas is transmitted to any point equally in all directions.
B) The modulus of elastic force during tension (or compression) of the body is directly proportional to the change in body length.
C) The forces of attraction between bodies depend on the mass of these bodies and the distance between them.
4. Express the pressure 10 kPa in Pa?
A) 10000Pa. B) 100Pa. B) 1000Pa.
5. A value equal to the ratio of the force acting perpendicular to the surface to the area of this surface is called ...
A) density. B) pressure. C) body weight.
6. A machine with a weight of 12,000 N has a support area of 2 m 2. Determine the pressure of the machine on the foundation?
A) 600 Pa. B) 24000 Pa. B) 6000 Pa.
7. How will the pressure of the book on the table change if you put it on its edge?
A) will not change. B) will decrease. C) will increase.
8. What is the formula for calculating body weight?
A) ρ = B) p = C) P = mg
Check answers. Swap sheets. Mutual verification
(For each correct answer, you get 1 point).
Learning new material.
Motivation: paper ball experiment
What surrounds us (air, atmosphere)
Guys, stretch your arms out, palms up. What do you feel? Is it hard for you? But air presses on your palms, and the mass of this air is equal to the mass of a KAMAZ loaded with bricks. That is about 10 tons!
Goal setting: So what presses on our hands - the atmosphere.
“The atmosphere brings the Earth to life. Oceans, seas, rivers, streams, forests, plants, animals, people - everything lives in the atmosphere and thanks to it. The earth floats in an airy ocean; its waves wash both the tops of the mountains and their foothills; and we live at the bottom of this ocean, covered by it from all sides, permeated through it ... Camille Flammarion (French astronomerXIX century)
What goals will we set for ourselves in this lesson?
What is atmosphere
Atmosphere properties
The role of the atmosphere in human life
So, let's begin:
What is atmosphere ? The air shell surrounding the Earth is called atmosphere(from the Greek. atmos- steam, air and sphere- ball).
The atmosphere, as shown by observations of the flight of artificial earth satellites, extends to an altitude of several thousand kilometers.
Due to the action of gravity, the upper layers of the air, like the water of the ocean, compress the lower layers. The air layer adjacent directly to the Earth is most compressed and, according to Pascal's law, transfers the pressure produced on it in all directions.
As a result of this, the earth's surface and the bodies on it, experience the pressure of the entire thickness of the air, or, as they usually say, experienceAtmosphere pressure.
Experiments with a glass of water, paper, medical syringe, pipette, balloon
Otto Guericke's Experience (Virtual Experience http://www.youtube.com/watch?v=j9MP4HZ83es)
Let us be convinced by experience. We take two metal hemispheres. We connect them together and use a pump to pump out the air. Atmospheric pressure will only act from the outside. As a result, the hemispheres will be firmly pressed one hemisphere to the other. If you disconnect the pump from them, you can hear the characteristic noise of the air. The hemispheres are separated by the weight of the load.
For the first time the atmospheric pressure was measured by the Italian physicist Evangelista Torricelli. (The Torricelli Experience)
Who is ready to explain the experience of Torricelli?
What do you know about the substance in the Torricell tube - mercury?
Student's answer: mercury is a rare metal, it is poisonous and unhealthy. Should be stored in a sealed container. Used in thermometers. Carefully work with these devices.
While conducting experiments, Torricelli noticed that the height of the column of mercury changed from time to time.
Output: atmospheric pressure does not remain constant, it changes. Especially changes before the weather changes.
The effect of atmospheric pressure on the human body is of great importance. ... For a normal life, a person, first of all, needs air. A person can live without food for up to five days, without air for no more than five minutes. On average, a person consumes about a kilogram of food per day, up to two and a half liters of water and oxygen from twenty kilograms of air. But the consumed air must meet certain requirements, otherwise it will cause chronic diseases. As a result of industrial emissions, the air in many cities is so polluted that the sun is almost invisible during the day. Industrial dust is one of the main types of air pollution. The damage caused by dust and ash is global. Dust clogs the mucous membranes of the respiratory organs and eyes, irritates the human skin, is a carrier of bacteria and viruses, reduces the illumination of streets, factory buildings, dwellings, causing excessive consumption of electricity. Atmospheric air is the source of respiration for humans, animals and vegetation, as well as the environment into which human, animal and plant waste is discharged. The atmosphere plays an important role in all natural processes. It serves as a reliable protection against harmful cosmic radiation, determines the climate of the area and the planet as a whole. The air of the atmosphere is one of the basic vital elements of the environment. To preserve it, to keep it clean means to preserve life on Earth.
Relaxation
Teacher: Are you tired? Let's do some breathing exercises. Correct breathing helps to improve the thought process. Place your hands on the diaphragm and take 3-4 deep breaths and exhalations.
Teacher: Have you ever wondered how we breathe?
When inhaling, the diaphragm increases the volume of the lungs. The air pressure in the lungs becomes less than atmospheric pressure. Atmospheric air enters the lungs.
When you exhale, the diaphragm compresses the lungs, and the volume of the lungs decreases. Therefore, the air pressure in the lungs becomes greater than atmospheric pressure. Air comes out.
Why can the human body withstand such loads?
This is achieved due to the fact that the pressure of the fluids that fill the vessels of the body balances the external atmospheric pressure.
IV. Securing the material.
Practical tasks (work in pairs):
1.) get a coin without getting your hands wet;
2) put the ball in the jar
3) pour water from a glass without touching it
- Introduction - page 2
- Material and method - page 3
- Conclusions - page 10
- 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.
- 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 things on Earth and man.
- Municipal budgetary educational institution
- "Secondary school number 3"
- Yemanzhelinsky municipal district
- How atmospheric pressure was discovered 4
- Torricelli 5
- The role of atmospheric pressure in the life of living organisms 6
- How was atmospheric pressure discovered?
- Torricelli
- The role of atmospheric pressure in the life of living organisms.
- Physics: Textbook. for 7 cl. general education. institutions / S. V. Gromov, N. A. Rodina. - M .: Education, 2001.
- Physics. 7th grade: textbook. for general education. institutions / A. V. Peryshkin. - 11th ed., Stereotype. - M .: Bustard, 2007.
- Zorin N.I., Elective course "Elements of biophysics" - M., "Vako", 2007.
- Syomke A.I., Entertaining materials for lessons - M., "Publishing house NTs ENAS", 2006.
- Volkov V.A., S.V. Gromova, Lesson development in physics, 7kl. - M. "Vako", 2005
- Sergeev IS, How to organize the project activities of students, M., "Arkti", 2006.
- From the Internet, CRC Handbook of Chemistry and Physics by David R. Lide, Editor-in-Chief 1997 Edition
Determine the height of the mountain if at the foot of 710, and at the top 720 mm Hg
Performed on the board.
3. The healing effect of medical glasses.
Many homes have medical cans - small, pot-bellied glass cups.
If, unfortunately, you catch a cold, the doctor will advise you to put cans. Mom will demonstrate their effect on you. And, imagining yourself as a martyr of science, you will generously agree, “sacrificing yourself, check their work and explain what happens in this case.
V. Lesson summary.
Assessment of pupils.
Reflection
1. Did you enjoy the lesson?
2. What new things have you learned?
3. What skills and abilities did you get?
4. What questions were the most interesting?
5. What were the difficulties?
Homework
What will be the result of Torricelli's experience on the moon?
1. The height of the column of mercury will be the same as on Earth: 760 mm.
2. The height of the column of mercury will be higher, because the force of gravity on the Moon is 6 times less.
3. The column of mercury will be less.
4. Mercury will pour out of the container.
Answer: 4. There is no atmosphere on the moon, so mercury cannot be retained.
Municipal autonomous educational institution
"Secondary school №16
Syktyvkar with in-depth study of individual subjects "
Proof of existence
atmospheric pressure
Toropov Ivan, 5 "v" class
Supervisor:
Toropova Irina Ivanovna,
Physics teacher
year 2013
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
4.Literature-p. eleven
1. Introduction
The goal is to provide evidence of the existence of atmospheric pressure.
Tasks:
2.Material and method
The date of the research 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- the pressure of atmospheric air on the 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, a certain amount of mercury spilled out of the tube, but then the height of the column remained almost unchanged.
He divided a glass tube 1 meter high into 1000 parts. What is 1 part equal to? (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 EFFECTS 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 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.
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 the earth's surface, atmospheric pressure varies from place to place and in time. Particularly important are the non-periodic changes in atmospheric pressure that determine the weather, associated with the emergence, development and destruction of slowly moving areas of high pressure (anticyclones) and relatively rapidly 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 confirming
existence of atmospheric pressure
Experience number 1
(water in a syringe).
Devices and materials: syringe, glass with tinted 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 experiment: 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. Outside atmospheric pressure drives 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 the 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: rinse the bottle with hot water. Drain the water and quickly close the bottle with a lid. 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: a soap dish with a suction cup, a blackboard, a 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 experiment: 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 is holding on.
Experience number 7.
(medical bank)
Devices and materials: medical banks, alcohol
The course of the experiment: moisten the 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: the fire squeezes out the 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;
- sudden changes 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 hotwith 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 poured down on the Earth like rain. While meteorites fly through the atmosphere, they encounter air resistance, heat up and burn up. 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 a great impact 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 farms are being built.
3.6 Conclusions.
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 S. F. Observe and explore for yourself. M., Education, 1966
Alekseeva Ksenia
The project "Experiments with Atmospheric Pressure" involves the exploration of the topic "Pressure" by the children, shows the students the importance of this topic in the life of living organisms on Earth, acquaints in detail with the project activities.
It is expected that creative work on the project will keep the children interested, as a result of which they will better master the basic theoretical concepts of the topic.
Project type: research
The implementation of the project contributes to the development of creative, research and communication skills of children, teaches them to receive information from various sources (including from the Internet), to comprehend it and apply it in their activities.
Download:
Preview:
Design and research work in physics
Experiments with atmospheric pressure.
Completed by: Alekseeva Ksenia
student of grade 7a.
Supervisor:
physics teacher Orzueva N.A.
2018
Introduction 3
Conclusion 8
Literature 9
Introduction
We live at the bottom of the air ocean. Above us - a huge thickness of air. The air shell surrounding the Earth is called atmosphere.
The Earth's atmosphere extends to an altitude of several thousand kilometers. And air, no matter how light it is, still has weight. Due to the action of gravity, the upper layers of the air, like the water of the ocean, compress the lower layers. The air layer adjacent directly to the Earth is compressed the most and, according to Pascal's law, transfers the pressure produced on it equally in all directions. As a result of this, the earth's surface and the bodies on it experience the pressure of the entire thickness of the air, or, as they usually say, experienceAtmosphere pressure.
How can living organisms withstand such enormous loads? How can atmospheric pressure be measured and what does it depend on?
Why does our health depend on changes in atmospheric pressure?
The purpose of my workto study the influence of atmospheric pressure on the processes taking place in living nature; find out the parameters on which the atmospheric pressure depends;
Project objectives. Examine information about atmospheric pressure. Observe the manifestations of atmospheric pressure. Find out the dependence of atmospheric pressure on altitude; dependence of the force of atmospheric pressure on the surface area of the body; the role of atmospheric pressure in wildlife.
Product: research work; textbook for conducting physics lessons in grade 7.
In my work, I have shown that the existence of atmospheric pressure can explain many of the phenomena that we encounter in everyday life. For this I conducted a number of entertaining experiments. I found out the dependence of the force of atmospheric pressure on the surface area and the value of atmospheric pressure on the height of the building, the value of atmospheric pressure in the life of wildlife.
The atmosphere is the Earth's air envelope, several thousand kilometers high.Deprived of the atmosphere, the Earth would become as dead as its companion the Moon, where alternately incinerating heat reigns, then freezing cold - + 130 0 С during the day and - 150 0 С at night. According to Pascal's calculations, the Earth's atmosphere weighs as much as a copper ball 10 km in diameter would weigh - five quadrillion (5,000,000,000,000,000) tons!
For the first time, the weight of the air led people to confusion in 1638, when the Duke of Tuscany's idea to decorate the gardens of Florence with fountains failed - the water did not rise above 10.3 m. The search for the reasons for the stubbornness of water and experiments with a heavier liquid - mercury, undertaken in 1643. Torricelli led to the discovery of atmospheric pressure. Torricelli found that the height of the column of mercury in his experiment did not depend on the shape of the tube or on its inclination. At sea level, the height of the mercury column has always been about 760mm.
The scientist suggested that the height of the liquid column is balanced by the air pressure. Knowing the height of the column and the density of the liquid, it is possible to determine the magnitude of the pressure of the atmosphere. The correctness of Torricelli's assumption was confirmed in 1648. Pascal's experience on the Pew de Dome. Due to the attraction of the Earth and insufficient speed, air molecules cannot leave the near-earth space. However, they do not fall to the surface of the Earth, but hover above it, because are in continuous thermal motion.
Due to the thermal motion and attraction of molecules to the Earth, their distribution in the atmosphere is uneven. At an atmosphere height of 2000-3000 km, 99% of its mass is concentrated in the lower (up to 30 km) layer. Air, like other gases, is well compressible. The lower layers of the atmosphere, as a result of the pressure on them from the upper layers, have a high air density. Normal atmospheric pressure at sea level averages 760 mm Hg = 1013 hPa. Air pressure and density decrease with altitude.
TORRICHELLI, Evangelista (Torricelli, Evangelista) (1608-1647), Italian physicist and mathematician. Born October 15, 1608 in Faenza.
In 1627 he came to Rome, where he studied mathematics under the guidance of B. Castelli, a friend and student of Galileo Galilei. Impressed by Galileo's writings on movement, he wrote his own essay on the same topic, entitled Treatise on Movement (Trattato del moto, 1640).
In 1641 he moved to Arcetri, where he became a student and secretary of Galileo, and later his successor at the Department of Mathematics and Philosophy at the University of Florence.
From 1642, after the death of Galileo, court mathematician of the Grand Duke of Tuscany and at the same time professor of mathematics at the University of Florence. The most famous works of Torricelli in the field of pneumatics and mechanics.
Together with V. Viviani, Torricelli carried out the first experiment to measure atmospheric pressure, inventing the first mercury barometer - a glass tube in which there is no air. In such a tube, mercury rises to a height of about 760 mm.
In 1644 he developed the theory of atmospheric pressure, proved the possibility of obtaining the so-called Torricellian void.
In his main work on mechanics "On the motion of freely falling and thrown heavy bodies" (1641), he developed Galileo's ideas about motion, formulated the principle of motion of centers of gravity, laid the foundations of hydraulics, and derived a formula for the rate of flow of an ideal fluid from a vessel.
The role of atmospheric pressure in the life of living organisms is very great. Many organs operate at the expense of atmospheric pressure.
We probably never thought about how we drink. And it is worth considering! When we drink, we “draw in” the liquid into ourselves. Why does the liquid rush into our mouths? When we drink, we expand the rib cage and thus discharge the air in the mouth; under the pressure of the outside air, the liquid rushes into the space where the pressure is less, and thus penetrates into our mouth.
The mechanism of inhalation and exhalation is based on the existence of atmospheric pressure.The lungs are located in the chest and separated from it and from the diaphragm by an airtight cavity called the pleural cavity. With an increase in the volume of the chest, the volume of the pleural cavity increases, and the air pressure in it decreases, and vice versa. Since the lungs are elastic, the pressure in them is regulated only by the pressure in the pleural cavity. When inhaling, the volume of the chest increases, due to which the pressure in the pleural cavity decreases; this causes an increase in lung volume of almost 1000 ml. At the same time, the pressure in them becomes less than atmospheric, and the air rushes through the airways into the lungs. When you exhale, the volume of the chest decreases, due to which the pressure in the pleural cavity increases, which causes a decrease in lung volume. The air pressure in them becomes higher than atmospheric pressure, and air from the lungs rushes into the environment.
Flies and tree frogs can stick to window glass thanks to tiny suction cups that create vacuum and atmospheric pressure keeps the suction cup on the glass.
Sticky fish have a suction surface consisting of a series 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 stronger.
The elephant uses atmospheric pressure whenever it is thirsty. His neck is short, and he cannot bend his head into the water, but lowers only his trunk and draws in air. Under the influence of atmospheric pressure, the trunk fills with water, then the elephant bends it and pours water into its mouth.
The suction effect of the swamp is explained by the fact that when the leg is raised, a rarefied space is formed under it. The overweight of atmospheric pressure in this case can reach 1000 N per leg area of an adult. However, the hooves of cloven-hoofed animals, when pulled out of the bog, pass air through their incision into the resulting rarefied space. The pressure above and below the hoof is evened out and the leg can be removed without much difficulty.
A person, getting into a space where the pressure is much lower than atmospheric pressure, for example, on high mountains or during takeoff or landing of an airplane, often experiences pain in the ears and even in the whole body. External pressure quickly decreases, the air inside us begins to expand, exerts pressure on various organs and causes pain.
When pressure changes, the rate of many chemical reactions changes, as a result of which the chemical equilibrium of the organism also changes. With an increase in pressure, there is an enhanced absorption of gases by body fluids, and with a decrease in pressure, the release of dissolved gases occurs. With a rapid decrease in pressure due to the intense release of gases, the blood seems to boil, which leads to a blockage of blood vessels, often fatal. This determines the maximum depth at which diving operations can be carried out (as a rule, not lower than 50 m). The lowering and raising of divers should be very slow so that the release of gases occurs only in the lungs, and not all at once in the entire circulatory system.
Conclusion.
The information obtained during the project will allow you to monitor your well-being, depending on changes in atmospheric pressure. The human body is affected by both low and high atmospheric pressure. With a reduced atmospheric pressure, there is an increase and deepening of breathing, an increase in heart rate (their strength is weaker), a slight drop in blood pressure, and changes in the blood are also observed in the form of an increase in the number of red blood cells.
With a decrease in atmospheric pressure, the partial pressure of oxygen also decreases, therefore, with the normal functioning of the respiratory and circulatory organs, a smaller amount of oxygen enters the body. As a result, the blood is insufficiently saturated with oxygen and does not fully deliver it to organs and tissues, which leads to oxygen starvation.
A very large amount of gases are dissolved in the interstitial fluid and in the tissues of the body. With increased pressure, gases do not have time to be released from the body. Gas bubbles appear in the blood; the latter can lead to vascular embolism, i.e. clogging them with gas bubbles. Carbon dioxide and oxygen, as gases that are chemically bound by the blood, are less dangerous than nitrogen, which, dissolving well in fats and lipoids, accumulates in large quantities in the brain and nerve trunks, which are especially rich in these substances. For especially sensitive people, high atmospheric pressure can be accompanied by pain in the joints and a number of brain phenomena: dizziness, vomiting, shortness of breath, loss of consciousness.
At the same time, training and hardening of the body plays an important role in prevention. It is necessary to go in for sports, systematically perform this or that physical work.
Eating at low atmospheric pressure should be high in calories, varied and rich in vitamins and mineral salts.
This should be especially taken into account by people who sometimes have to work at high or low atmospheric pressure (divers, climbers, when working on high-speed lifting mechanisms), and these deviations from the norm are sometimes within significant limits
Literature:
Water and water games are loved by many children. That is why water is an excellent tool for carrying out various educational games and experiences as well. The pressure of water and air is difficult to demonstrate in everyday life, because for a child these concepts are somewhat abstract. Therefore, we are helped by simple and visual experiments with water in which the child can take a direct part.
Earlier, we have already touched on the topic of atmospheric pressure and water pressure, when we carried out and. Today we will delve deeper into the topic and consider the principle of communicating vessels, methods of artificially increasing pressure and the dependence of pressure on the level of depth. You do not need any special equipment for this series of experiments. You will find everything you need at home: two transparent plastic bottles with lids, matches, a piece of plasticine, a funnel for water, a dye for clarity (optional).
To demonstrate the first experiment, we make a hole on the side of the plastic bottle. I first pierced the wall with a thick needle and enlarged the hole with nail scissors so that the cocktail tube could be inserted. Insert the tube and hermetically seal the gap between the tube and the walls of the bottle.
We direct the end of the tube up and, using a funnel, pour colored water into the bottle to a height above the hole in the wall, but below the end of the tube. Pay attention to the child that the water has risen up the straw and stopped at the same level as in the bottle.
This phenomenon is familiar to us as the law of communicating vessels, when the level of liquid in each of the communicating vessels is established at the same level, if the liquids in them are the same and the pressure above each is the same.
Now we lower the end of the tube down, and the water flows out of the bottle unhindered until the water level drops below the hole in the wall. 
This phenomenon is widely used in everyday life: water supply, and even an ordinary kettle and watering can are a clear example of communicating vessels. Talk to your child about why you can't boil a full kettle of water if the spout is flush or below the lid.
Closed bottle experience
Since the phrase “equal pressure over both vessels” means little to a preschool child, we turn to the next two experiments. In the first, we will reduce the pressure, and in the second artificially increase.
So, through the funnel, quickly pour a lot of water into the bottle and tighten the lid. Let's see what happened. The water in the bottle is above the end of the straw, but no water comes out. Why?
The bottle no longer receives air, which pushed excess water out through the straw. Of course, in fact, we did not reduce the pressure, but we limited the effect of atmospheric pressure on the surface of the water in the bottle and got this result.
This time we will increase the pressure in the bottle. To do this, remove the lid and wait until some of the water flows out, so that one level is established. And now we inflate the balloon, close it with a clothespin and put the free part on the neck of the bottle.
Do you want to play with your child easily and with pleasure?
When all the preparations are over, we remove the clothespin and observe the fountain pouring out of the tube. The water will be poured out until the entire balloon is deflated or until the water drops below the end of the tube in the bottle.
Everything is clear here, the air from the balloon pushes the water out of the bottle through the cocktail tube. In other words, the increased pressure above one of the communicating vessels changes the level of fluid in them.
Different streams of water
The following experiment clearly demonstrates the dependence of water pressure on depth.
To carry it out, we need a bottle with three identical holes in the wall at different heights. Now, through the funnel, quickly pour water into the bottle and observe the trickles that beat from the bottle.
Pay attention to the child that from the lower hole it is the strongest and hits farther than the others, while the jet from the upper hole is the weakest and shortest. This is due to the fact that there is more water above the lower hole, and it presses on the walls of the bottles with greater force, and at the top the amount of water to the hole is less and, accordingly, it presses on the walls less.
These phenomena are taken into account in the work of a diver and a submariner, since diving under the water a person experiences the pressure of the water the more, the deeper he submerges. In this regard, the maximum depths to which you can dive safely for health and various protective suits that help to work at great depths have been established.
Immersion in water
In conclusion, invite your child to watch diving matches. To do this, pour a full bottle of water, cut off the sulfur heads from the matches and throw them into a bottle, which we tightly tighten with a lid. Immediately, our divers will swim on the surface, but if we squeeze the bottle with force, the sulfur heads will begin to smoothly sink to the bottom. If we stop squeezing, they will go up again. 
Why it happens? When we squeeze, we increase the pressure inside the bottle, so the divers sink to the bottom, and when the pressure decreases, they float back up.
Since these experiments do not require special equipment, you can do them outdoors on warm days, on the beach, or even at a picnic as entertainment for children and adults.
