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Presentation on the topic: Earth's atmosphere: its composition and structure

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Atmosphere (from the Greek atmos - steam and spharia - ball) is the air shell of the Earth, rotating with it. The development of the atmosphere was closely connected with the geological and geochemical processes taking place on our planet, as well as with the activities of living organisms. Atmosphere (from the Greek atmos - steam and spharia - ball) is the air shell of the Earth, rotating with it. The development of the atmosphere was closely connected with the geological and geochemical processes taking place on our planet, as well as with the activities of living organisms. The lower boundary of the atmosphere coincides with the surface of the Earth, since air penetrates into the smallest pores in the soil and is dissolved even in water. The upper limit at an altitude of 2000-3000 km gradually passes into outer space. Oxygen-rich atmosphere makes life possible on Earth. Atmospheric oxygen is used in the process of breathing by humans, animals, and plants.

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The troposphere is the lowest layer of the atmosphere, the thickness of which is 8-10 km above the poles, 10-12 km in temperate latitudes, and 16-18 km above the equator. The troposphere is the lowest layer of the atmosphere, the thickness of which is 8-10 km above the poles, 10-12 km in temperate latitudes, and 16-18 km above the equator. The air in the troposphere is heated from the earth's surface, i.e. from land and water. Therefore, the air temperature in this layer decreases with height by an average of 0.6 °C for every 100 m. At the upper boundary of the troposphere, it reaches -55 °C. At the same time, in the region of the equator at the upper boundary of the troposphere, the air temperature is -70 °С, and in the region of the North Pole -65 °С. About 80% of the mass of the atmosphere is concentrated in the troposphere, almost all water vapor is located, thunderstorms, storms, clouds and precipitation occur, and vertical (convection) and horizontal (wind) air movement occurs. We can say that the weather is mainly formed in the troposphere.

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Stratosphere - a layer of the atmosphere located above the troposphere at an altitude of 8 to 50 km. The color of the sky in this layer appears purple, which is explained by the rarefaction of the air, due to which the sun's rays almost do not scatter. Stratosphere - a layer of the atmosphere located above the troposphere at an altitude of 8 to 50 km. The color of the sky in this layer appears purple, which is explained by the rarefaction of the air, due to which the sun's rays almost do not scatter. The stratosphere contains 20% of the mass of the atmosphere. The air in this layer is rarefied, there is practically no water vapor, and therefore clouds and precipitation are almost not formed. However, stable air currents are observed in the stratosphere, the speed of which reaches 300 km / h. Ozone is concentrated in this layer (ozone screen, ozonosphere), a layer that absorbs ultra-violet rays, preventing them from reaching the Earth and thereby protecting living organisms on our planet. Due to ozone, the air temperature at the upper boundary of the stratosphere is in the range from -50 to 4-55 °C. Between the mesosphere and the stratosphere there is a transitional zone - the stratopause.

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The mesosphere is a layer of the atmosphere located at an altitude of 50-80 km. The air density here is 200 times less than at the surface of the Earth. The color of the sky in the mesosphere appears black, stars are visible during the day. The air temperature drops to -75 (-90)°С. The mesosphere is a layer of the atmosphere located at an altitude of 50-80 km. The air density here is 200 times less than at the surface of the Earth. The color of the sky in the mesosphere appears black, stars are visible during the day. The air temperature drops to -75 (-90)°С. At an altitude of 80 km, the thermosphere begins. The air temperature in this layer rises sharply to a height of 250 m, and then becomes constant: at a height of 150 km it reaches 220-240 °C; at an altitude of 500-600 km it exceeds 1500 °C.

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In the mesosphere and thermosphere, under the action of cosmic rays, gas molecules break up into charged (ionized) particles of atoms, so this part of the atmosphere is called the ionosphere - a layer of very rarefied air located at an altitude of 50 to 1000 km, consisting mainly of ionized oxygen atoms, molecules nitrogen oxides and free electrons In the mesosphere and thermosphere, under the action of cosmic rays, gas molecules break up into charged (ionized) particles of atoms, so this part of the atmosphere is called the ionosphere - a layer of very rarefied air located at an altitude of 50 to 1000 km, consisting mainly of ionized oxygen atoms, nitric oxide molecules and free electrons In the ionosphere, auroras arise - the glow of rarefied gases under the influence of electrically charged particles flying from the Sun - and sharp fluctuations in the magnetic field are observed.

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The atmosphere is a mixture of gases, consisting of nitrogen (78.08%), oxygen (20.95%), carbon dioxide (0.03%), argon (0.93%), not a large number helium, neon, xenon, krypton (0.01%), ozone and other gases, but their content is negligible (Table 1). The modern composition of the Earth's air was established more than a hundred million years ago, but the sharply increased human production activity nevertheless led to its change. At present, there is an increase in the CO2 content by about 10-12%. The atmosphere is a mixture of gases consisting of nitrogen (78.08%), oxygen (20.95%), carbon dioxide (0.03%), argon (0.93%), a small amount of helium, neon, xenon, krypton (0.01%), ozone and other gases, but their content is negligible (Table 1). The modern composition of the Earth's air was established more than a hundred million years ago, but the sharply increased human production activity nevertheless led to its change. At present, there is an increase in the CO2 content by about 10-12%.

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Presentation on the topic Atmosphere
The presentation was made by a 5th grade student Violetta Sidorova Teacher: Kardanova Yu.R.

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targets and goals
deepen knowledge about the atmosphere, study the composition of air, the structure of the atmosphere and the characteristics of the layers, the importance of the atmosphere for the nature of the Earth; building knowledge about geographical envelope- the atmosphere, as the source of the existence of life.

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Atmosphere - the air shell of the Earth
The atmosphere is the outermost layer of the Earth. Its thickness is approximately 2000-3000 km. The atmosphere has no upper boundary.

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Composition of the atmosphere
The Earth's atmosphere is made up of a mixture of gases. Basically, these are Nitrogen (N2) - 78%, oxygen (O2) - 21% and other gases - carbon dioxide, water vapor, ozone, helium, hydrogen, argon, etc. - one%.

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The structure of the atmosphere
The thickness of the atmosphere is about 3 thousand km. Several layers are distinguished in it, which differ from each other in temperature and composition of gases. The lower layer - the troposphere - is the surface of the Earth, but this boundary is relative. Next comes the stratosphere. Even higher - mesosphere, thermosphere, exosphere. These are the upper layers of the atmosphere, which pass into outer space at an altitude of 2-3 thousand km. above the surface of the earth.

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The troposphere is the lowest layer of the atmosphere, the thickness of which is 8-10 km above the poles, 10-12 km in temperate latitudes, and 16-18 km above the equator. The air in the troposphere is heated from the earth's surface, i.e. from land and water. Therefore, the air temperature in this layer decreases with height by an average of 0.6 °C for every 100 m. At the upper boundary of the troposphere, it reaches -55 °C. At the same time, in the region of the equator at the upper boundary of the troposphere, the air temperature is -70 °С, and in the region of the North Pole -65 °С. About 80% of the mass of the atmosphere is concentrated in the troposphere, almost all water vapor is located, thunderstorms, storms, clouds and precipitation occur, and vertical (convection) and horizontal (wind) air movement occurs. We can say that the weather is mainly formed in the troposphere.
Troposphere

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Stratosphere - a layer of the atmosphere located above the troposphere at an altitude of 8 to 50 km. The color of the sky in this layer appears purple, which is explained by the rarefaction of the air, due to which the sun's rays almost do not scatter. The stratosphere contains 20% of the mass of the atmosphere. The air in this layer is rarefied, there is practically no water vapor, and therefore clouds and precipitation are almost not formed. However, stable air currents are observed in the stratosphere, the speed of which reaches 300 km / h. Ozone is concentrated in this layer (ozone screen, ozonosphere), a layer that absorbs ultraviolet rays, preventing them from passing to the Earth and thereby protecting living organisms on our planet. Due to ozone, the air temperature at the upper boundary of the stratosphere is in the range from -50 to 4-55 °C. Between the mesosphere and the stratosphere there is a transitional zone - the stratopause.
Stratosphere

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The mesosphere is a layer of the atmosphere located at an altitude of 50-80 km. The air density here is 200 times less than at the surface of the Earth. The color of the sky in the mesosphere appears black, stars are visible during the day. The air temperature drops to -75 (-90)°C. At an altitude of 80 km, the thermosphere begins. The air temperature in this layer rises sharply to a height of 250 m, and then becomes constant: at a height of 150 km it reaches 220-240 °C; at an altitude of 500-600 km it exceeds 1500 °C.
Mesosphere and thermosphere

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The value of the atmosphere
Air is needed for breathing by all living organisms. The ozone contained in the stratosphere protects living organisms from harmful ultraviolet radiation from the Sun. As a result of human activities, the air becomes dirty. The ozone layer is being destroyed. We need to keep the air clean!

(slide 1 computer presentation) Today I will tell you about the atmosphere, its structure and what role the atmosphere plays in the life of the Earth.

(slide 2 computer presentation)“We live at the bottom of the ocean of air,” these words belong to the famous Italian scientist Evangelisto Torricelli.

(slide 3 computer presentation)The ancient Greeks thought that the air around us is evaporated water, and called the shell surrounding the planet - ATMOSPHERE (from the Greek words(atmos - steam) and (sphere - ball).

(slide 4 computer presentation).If a globe with a diameter of 35 cm is mentally surrounded by a layer of air 3 cm thick, then a model will be obtained showing the comparative dimensions of the Earth and the atmosphere. Our atmosphere is actually more than 1000 km thick.

Is the thickness of the atmosphere the same at different altitudes?

(slide 5-6 computer presentation).No, she's different. The atmosphere is conditionally divided into several layers - the troposphere, stratosphere, mesosphere, thermosphere, exosphere.

To As shown by spacecraft flights, the atmosphere at different altitudes is different. The boundaries of conditional layers are as follows:

1. troposphere - up to 16 km;
2. stratosphere - up to 50 km;
3. mesosphere - up to 80 km;
4. thermosphere - up to 150 km;
5. exosphere - 150 km and above passing into outer space.

(slide 7 computer presentation). 90% of the total air mass is concentrated in the troposphere. Its thickness is not the same everywhere. Above the equator - 17 km, in the polar regions - 8-9 km, in the middle latitudes - 10-11 km. Why do you think?

AT At equatorial latitudes, the air heats up strongly, expands and increases in volume. In polar latitudes, the opposite is true.

(slide 8 computer presentation). H The names of the layers of the atmosphere come from Greek and Latin words:

1. troposphere - “tropos” - the Greek word for turn. It contains all the water vapor, it is the birthplace of clouds and all natural phenomena;
2. stratosphere - "stratum" Latin word - flooring, layer. Here is 1/5 of the atmosphere, this is the realm of cold, mother-of-pearl clouds, consisting of ice crystals and droplets of supercooled liquid, the sky here is black or dark purple;
3. mesosphere - "meso" - the Greek word - medium, intermediate; the air here is rarefied, contains ozone, silvery clouds, which are visible only at dusk;
4. thermosphere - "thermo" - the Greek word - heat; here is an unprecedented heat with a strong discharge;
5. exosphere - the outer shell of the atmosphere, extending for 500-600 km, this is the scattering layer

Let us compare the masses and volumes of the layers of the atmosphere, consideringslide 8 computer presentation.

(slide 9 computer presentation).

"What kind aircrafts do you know which can climb to different heights?” Airplane, it flies on the border of the troposphere and stratosphere; stratostat in the stratosphere; radiosonde flies in the stratosphere;spaceship in the thermosphere; the first Soviet artificial earth satelliteat the boundary of the thermosphere and exosphere;meteorological satellite in the exosphere.

Consider the last vertical axis in the figure and answer the question:

How does the density of the atmosphere change with height? The density of the atmosphere decreases with height. Measurements show that air density decreases rapidly with height. So, at an altitude of 5.5 km above sea level, the air density is 2 times less than at the Earth's surface. At an altitude of 11 km, 4 times less, and so on ... the higher, the rarer the air. And finally, in the highest layers - hundreds and thousands of kilometers above the Earth - the atmosphere gradually turns into airless space. Thus, the atmosphere does not have a clear boundary.

What is air? What are we breathing? Element? Wind? Something homogeneous? Complicated connection?(slide 10 computer presentation).

Until the middle of the 18th century, scientists did not know that air is a mixture of gases. Scientists from many countries and different eras dealt with this problem:

Robert Boyle (England), M.V. Lomonosov (Russia), Carl Scheele (Sweden), Joseph Priestley (England), Antoine Lavoisier (France), Henry Cavendish (England), William Ramsay (England).

(slide 11 computer presentation). In accordance with modern ideas air contains gases. Consider a pie chart. We see that nitrogen - 78%, oxygen - 21%, inert gases - 0.94%, carbon dioxide - 0.03%

There are variable components in the air, they account for 0.03%. What are these variable components?

These are oxides of nitrogen, sulfur, carbon monoxide, ammonia, elemental sulfur, hydrogen sulfide, water and dust. These substances enter the atmosphere naturally. Water in the air determines its humidity, contributes to the formation of clouds and precipitation. The rest of the substances play a negative role. They are air pollutants.

(slide 12 computer presentation)- when a volcano erupts, sulfur dioxide, hydrogen sulfide, elemental sulfur enter the atmosphere.

- Dust storms contribute to the formation of dust.

– the penetration of nitrogen oxides into the atmosphere is facilitated by lightning discharges, during which nitrogen and oxygen in the air react with each other, as well as forest fires, burning of peat bogs.

Destruction processes organic matter accompanied by the formation of various gaseous sulfur compounds.

The ozone layer is important(slide 13 computer presentation)located in the statosphere. Ozone is formed in the upper rarefied layers under the influence of ultraviolet rays.

(animation - slide 14 of the computer presentation).

Why does the Earth have an atmosphere? What forces act on the air?(slide 15 computer presentation).

Air volume 1m 3 has a mass of 1.3 kg.(slide 16 computer presentation).From the side of the Earth, the air, like any other body, is affected by the force of gravity. It is attracted to the earth. But the molecules of the gases that make up the atmosphere do not fall on the surface of the Earth. They are in constant chaotic motion.

P Why, then, do molecules not leave the Earth? To leave the Earth, a molecule, like a rocket, needs to have a speed of 11.2 km / s (second space velocity)(slide 17 computer presentation), but the speed of movement of gas molecules is much less than this value. So, two factors - chaotic movement and the action of gravity, lead to the fact that the molecules are located around the Earth, forming an atmosphere.

In the solar system, the planets have an atmosphere, but it is different.

(slide 18 computer presentation)- on Venus and Mars - carbon dioxide, on the giant planets - helium, methane, ammonia(slide 19 computer presentation), there is no atmosphere on the Moon and Mercury(slide 20 computer presentation).

In 1862, the English naturalist James Glaisher and a friend set out to travel in a hot air balloon wearing only jackets.(slide 21 computer presentation). Having risen to a height of 11 km, the travelers lost consciousness and suffered severe frostbite. They did not know that for every 1,500 m of elevation, the temperature drops by 8○ C.

Why is this happening?

(slide 22 computer presentation).Difficulties encountered by travelers:

1. Clouds are a thick cold fog in which nothing is visible;

2. Lack of oxygen, because. with a change in altitude, the air becomes rarefied;

3. Cold - for every kilometer of altitude, t ° drops by 6 ° С;

(slide 23 computer presentation). H at high altitudes, the air is rarefied and the molecules rarely collide, so their speed decreases and the air temperature drops.But such a picture in the troposphere at an altitude of 17 km. At this altitude above the tropics, the temperature is -75 0 C, in the stratosphere the temperature rises to 0 0 C, in the mesosphere drops to -85 0 C, in the thermosphere at an altitude of 400 km, the temperature is 727 0 -927 0 C, exosphere temperature 1000 0 - 1200 0 С.

(slide 24 computer presentation).

How do spaceships fly at such heights? BUT the atmosphere is very rarefied, almost reaching a vacuum. Such an atmosphere does not resist ships, which allows them to remain in orbit for years.

(slide 25 computer presentation).

Take care of your planet!

There is one garden planet

In this cold space

Only here the forests are noisy,

Birds calling migratory.

And dragonflies are only here

They look into the river in surprise.

Here in the grass lives carelessly

chirping songbird grasshopper,

Young wind, bully,

Tickles the old ocean

graceful dolphins

Waltz dance and sing

In general, they live happily.

Here only the morning is golden,

The air is soft blue

Breathe easily and freely.

Sometimes we forget:

Air is leased to us

He is one for all earthlings.

For life to triumph

We need to protect the air.

Take care of your planet

After all, there is no other in the world!

Galina Marshanova.

(slide 26 computer presentation).

Atmosphere value:

1. Protects the earth from overheating and hypothermia.
2. Protects from meteorites.
3. Protects from ultraviolet radiation.
4. Needed for breathing.
5. Aesthetic value

(animation - slide 27 of the computer presentation).

(animation - slide 28 of the computer presentation).

The role of the atmosphere in the life of the Earth

(slide 29 computer presentation).

(slide 30 computer presentation).

1. Air is essential for all life on earth.
2. Atmosphere - the Earth's armor - protects against meteorite bombardment
3. The ozone layer traps harmful cosmic rays
4. Atmosphere is the world of sounds
5. Without an atmosphere, the Earth would be lifeless like the Moon, there would be no rivers, lakes, seas on it.
6. The atmosphere is the Earth's clothing, it will not allow heat to escape into space.

The atmosphere is the air shell of the Earth, and in order to conduct a geography lesson on this topic, there is a good presentation on grade 6 geography, which the World of Geography offered you to download, as usual, for free. Students of the 6th grade in the lesson learn a lot of interesting things about the atmosphere, about which they seem to be well aware of. But in fact, the situation is such that they know about the composition of the air they breathe, but most likely they have not heard anything about the stratosphere. Therefore, there is a reason to download the presentation, and based on its slides, show and tell interesting information about the atmosphere.

View presentation content
"composition"

What is the atmosphere made of? and how it works

Are there children, a blanket,

To cover the whole earth

To have enough for everyone

And besides, it was not visible?

Neither fold nor unfold

Feel or see?

Let rain and light through

There is, but it seems to be not?

Atmosphere is the atmosphere of the earth

Composition of the atmosphere

OXYGEN. Plants supply oxygen in the atmosphere.

CARBON DIOXIDE. Carbon dioxide accumulates in the atmosphere as a result of volcanic eruptions, the respiration of living organisms, and the combustion of fuels.

WATER VAPOR. Water vapor enters the air due to the evaporation of water.

Carbon dioxide, together with water vapor, "protects" the heat of our planet: the atmosphere transmits more energy from the Sun to the earth's surface than the Earth gives off to the surrounding outer space.

OZONE. Ozone is formed from oxygen by the action of sunlight and electrical discharges. It has the smell of freshness, such as we feel after a thunderstorm. There is very little of this gas in the atmosphere, but at an altitude of 20-30 km there is a layer of air with a higher ozone content. It is called the ozone shield. He, like a shield, protects all living things from the destructive radiation of the Sun.

IMPURITIES. In addition to gases in the air of the atmosphere, there are also solid impurities. These small particles are formed as a result of the destruction of rocks, volcanic eruptions, dust storms, and fuel combustion. On the one hand, they pollute the air, but, on the other hand, the formation of clouds is impossible without them.

Troposphere - this is the lower layer of the atmosphere, extending to a height of 8-10 km above the poles, 10-12 km in the middle latitudes and 16-18 km above the equator.

The troposphere contains more than 4 / 5 all atmospheric air. Moreover, more than half of it is concentrated up to a height of 5 km. The air temperature here decreases with height and reaches -55 C at the upper limit. Almost all atmospheric moisture is contained in the troposphere. It forms clouds that bring rain, snow, hail. Here there is a constant movement of air, wind is formed. The life of man and plants takes place in the troposphere.

Stratosphere - this is the layer of the atmosphere lying above the troposphere up to a height of 55 km.

The air in the stratosphere is thinner than in the troposphere. It almost does not form clouds, since there is very little water vapor. The air temperature here increases with height and near the upper boundary is close to 0 °C.

Above the stratosphere, several more atmospheric layers stand out, which gradually pass into airless space.

Run a test

1. The atmosphere is the shell

a. Gas

b. Water

in. salty

2. The lowest layer of the atmosphere:

a. Stratosphere

b. Troposphere

in. upper atmosphere

Run a test

3. The oxygen in the air is:

4. In the troposphere are formed:

a. Clouds

b. Ultra-violet rays

in. ground water

Definition Atmosphere (from other Greek τμός steam and σφα ρα ball) is a gaseous shell surrounding the planet Earth, one of the geospheres. Its inner surface covers the hydrosphere and partially the earth's crust, while its outer surface borders on the near-Earth part of outer space. The totality of sections of physics and chemistry that study the atmosphere is commonly called atmospheric physics. The atmosphere determines the weather on the surface of the Earth, meteorology deals with the study of weather, and climatology deals with long-term climate variations.

The boundary of the atmosphere The atmosphere is considered to be that area around the Earth in which the gaseous medium rotates together with the Earth as a whole; With this definition, the atmosphere passes into interplanetary space gradually; in the exosphere, which begins at an altitude of about 1000 km from the Earth's surface, the boundary of the atmosphere can also be conditionally drawn along an altitude of 1300 km. According to the definition proposed by the International Aviation Federation, the boundary of the atmosphere and space is drawn along the Karman line, located at an altitude of about 100 km, where aeronautics becomes completely impossible. NASA uses 122 kilometers as the boundary of the atmosphere; recent experiments refine the boundary between the Earth's atmosphere and the ionosphere as being at an altitude of 118 kilometers.

Physical properties The total mass of air in the atmosphere (5.15.3)·10 18 kg. Of these, the mass of dry air is (5.1352 ± 0.0003) 10 18 kg, the total mass of water vapor is on average 1.27 10 16 kg. The molar mass of clean dry air is 28.966 g / mol, the density of air at the sea surface is approximately 1.2 kg / m 3. The pressure at 0 ° C at sea level is 101.325 kPa; critical temperature 140.7 °C (~132.4 K); critical pressure 3.7 MPa; C p at 0 °C 1.0048 10 3 J/(kg K), C v 0.7159 10 3 J/(kg K) (at 0 °C). Solubility of air in water (by mass) at 0 °C 0.0036%, at 25 °C 0.0023%. For "normal conditions" at the surface of the Earth are taken: density 1.2 kg / m 3, barometric pressure 101.35 kPa, temperature +20 ° C and relative humidity 50%. These conditional indicators have a purely engineering value.

The atmosphere of the Earth arose as a result of two processes: the evaporation of the substance of cosmic bodies during their fall to the Earth and the release of gases during volcanic eruptions (degassing of the earth's mantle). With the release of the oceans and the emergence of the biosphere, the atmosphere changed due to gas exchange with water, plants, animals and their decomposition products in soils and swamps. At present, the Earth's atmosphere consists mainly of gases and various impurities (dust, water drops, ice crystals, sea salts, combustion products). The concentration of gases that make up the atmosphere is almost constant, with the exception of water (H 2 O) and carbon dioxide (CO 2). The content of water in the atmosphere (in the form of water vapor) ranges from 0.2% to 2.5% by volume, and depends mainly on latitude. In addition to the gases indicated in the table, the atmosphere contains Cl 2, SO 2, NH 3, CO, O 3, NO 2, hydrocarbons, HCl, HF, HBr, HI, Hg vapor, I 2, Br 2, as well as NO and many other gases in small quantities. In the troposphere there is constantly a large amount of suspended solid and liquid particles (aerosol). Radon (Rn) is the rarest gas in the Earth's atmosphere.

The structure of the atmosphere The boundary layer of the atmosphere The lower layer of the atmosphere adjacent to the Earth's surface (1-2 km thick) in which the influence of this surface directly affects its dynamics. Troposphere Its upper limit is at an altitude of 810 km in polar, 1012 km in temperate and 1618 km in tropical latitudes; lower in winter than in summer. The lower, main layer of the atmosphere contains more than 80% of the total mass of atmospheric air and about 90% of all water vapor present in the atmosphere. In the troposphere, turbulence and convection are highly developed, clouds appear, cyclones and anticyclones develop. The temperature decreases with height with an average vertical gradient of 0.65°/100 m. Tropopause The transitional layer from the troposphere to the stratosphere, the layer of the atmosphere in which the decrease in temperature with height stops. Stratosphere The layer of the atmosphere located at an altitude of 11 to 50 km. A slight change in temperature in the 1125 km layer (lower layer of the stratosphere) and its increase in the 2540 km layer from 56.5 to 0.8 °C (upper stratosphere or inversion region) are typical. Having reached a value of about 273 K (almost 0 °C) at an altitude of about 40 km, the temperature remains constant up to an altitude of about 55 km. This area constant temperature called the stratopause and is the boundary between the stratosphere and the mesosphere. Thermopause Region of the atmosphere adjacent to the top of the thermosphere. In this region, the absorption of solar radiation is insignificant and the temperature does not actually change with height. Stratopause The boundary layer of the atmosphere between the stratosphere and the mesosphere. AT vertical distribution temperature has a maximum (about 0 °C). Mesosphere The mesosphere begins at an altitude of 50 km and extends up to 8090 km. The temperature decreases with height with an average vertical gradient of (0.250.3)°/100 m. The main energy process is radiant heat transfer. Complex photochemical processes involving free radicals, vibrationally excited molecules, etc., cause atmospheric luminescence. Mesopause The transitional layer between the mesosphere and the thermosphere. There is a minimum in the vertical temperature distribution (about 90 °C).

Exosphere (scattering sphere) The exosphere is the scattering zone, the outer part of the thermosphere located above 700 km. The gas in the exosphere is highly rarefied, and hence its particles leak into interplanetary space (dissipation). Up to a height of 100 km, the atmosphere is a homogeneous, well-mixed mixture of gases. In higher layers, the distribution of gases in height depends on their molecular masses, the concentration of heavier gases decreases faster with distance from the Earth's surface. Due to the decrease in gas density, the temperature drops from 0 °C in the stratosphere to 110 °C in the mesosphere. However, the kinetic energy of individual particles at altitudes of km corresponds to a temperature of ~150 °C. Above 200 km, significant fluctuations in temperature and gas density are observed in time and space. At an altitude of about km, the exosphere gradually passes into the so-called near space vacuum, which is filled with highly rarefied particles of interplanetary gas, mainly hydrogen atoms. But this gas is only part of the interplanetary matter. The other part is composed of dust-like particles of cometary and meteoric origin. In addition to extremely rarefied dust-like particles, electromagnetic and corpuscular radiation of solar and galactic origin penetrates into this space. Overview The troposphere accounts for about 80% of the mass of the atmosphere, the stratosphere for about 20%; the mass of the mesosphere is not more than 0.3%, the thermosphere is less than 0.05% of the total mass of the atmosphere. Based on the electrical properties in the atmosphere, the neutrosphere and ionosphere are distinguished. Depending on the composition of the gas in the atmosphere, homosphere and heterosphere are distinguished. The heterosphere is an area where gravity has an effect on the separation of gases, since their mixing at such a height is negligible. Hence follows the variable composition of the heterosphere. Below it lies a well-mixed, homogeneous part of the atmosphere, called the homosphere. The boundary between these layers is called the turbopause and lies at an altitude of about 120 km.

Other properties of the atmosphere and the impact on the human body Already at an altitude of 5 km above sea level, an untrained person develops oxygen starvation and, without adaptation, a person's performance is significantly reduced. This is where the physiological zone of the atmosphere ends. Human breathing becomes impossible at an altitude of 9 km, although up to about 115 km the atmosphere contains oxygen. The atmosphere provides us with the oxygen we need to breathe. However, due to the drop in the total pressure of the atmosphere as you rise to a height, the partial pressure of oxygen also decreases accordingly. The human lungs constantly contain about 3 liters of alveolar air. The partial pressure of oxygen in the alveolar air at normal atmospheric pressure is 110 mm Hg. Art., pressure of carbon dioxide 40 mm Hg. Art., and water vapor 47 mm Hg. Art. With increasing altitude, the oxygen pressure drops, and the total pressure of water vapor and carbon dioxide in the lungs remains almost constant at about 87 mm Hg. Art. The flow of oxygen into the lungs will completely stop when the pressure of the surrounding air becomes equal to this value. At an altitude of about 1920 km, the atmospheric pressure drops to 47 mm Hg. Art. Therefore, at this height, water and interstitial fluid begin to boil in the human body. Outside a pressurized cabin at these altitudes, death occurs almost instantly. Thus, from the point of view of human physiology, "space" begins already at an altitude of 1519 km.

The dense layers of air, the troposphere and stratosphere, protect us from the damaging effects of radiation. With sufficient rarefaction of air, at altitudes of more than 36 km, ionizing radiation, primary cosmic rays, has an intense effect on the body; at altitudes of more than 40 km, the ultraviolet part of the solar spectrum, which is dangerous for humans, operates. As we rise to an ever greater height above the Earth's surface, such phenomena that are familiar to us observed in the lower layers of the atmosphere, such as the propagation of sound, the emergence of aerodynamic lifting force and resistance, heat transfer by convection, etc. In rarefied layers of air, the propagation of sound is impossible. Up to altitudes of km, it is still possible to use air resistance and lift for controlled aerodynamic flight. But starting from the heights of km, the concepts of the number M and sound barrier lose their meaning: the conditional Karman line passes there, beyond which the area of ​​​​purely ballistic flight begins, which can be controlled only using reactive forces. At altitudes above 100 km, the atmosphere is also deprived of another remarkable property of the ability to absorb, conduct and transmit thermal energy by convection (that is, by means of air mixing). This means that various elements of equipment, equipment of the orbital space station will not be able to be cooled from the outside in the way it is usually done on an airplane, with the help of air jets and air radiators. At such a height, as in general in space, the only way heat transfer is thermal radiation.

The history of the formation of the atmosphere According to the most common theory, the Earth's atmosphere has been in three different compositions throughout the history of the latter. Initially, it consisted of light gases (hydrogen and helium) captured from interplanetary space. This is the so-called primary atmosphere. At the next stage, active volcanic activity led to the saturation of the atmosphere with gases other than hydrogen (carbon dioxide, ammonia, water vapor). This is how the secondary atmosphere was formed. This atmosphere was restorative. Further, the process of formation of the atmosphere was determined by the following factors: leakage of light gases (hydrogen and helium) into interplanetary space; chemical reactions occurring in the atmosphere under the influence of ultraviolet radiation, lightning discharges and some other factors. Gradually, these factors led to the formation of a tertiary atmosphere, characterized by much less hydrogen and much more nitrogen and carbon dioxide (formed as a result of chemical reactions from ammonia and hydrocarbons).

Nitrogen The formation of a large amount of nitrogen N 2 is due to the oxidation of the ammonia-hydrogen atmosphere by molecular oxygen O 2, which began to come from the surface of the planet as a result of photosynthesis, starting from 3 billion years ago. Nitrogen N 2 is also released into the atmosphere as a result of the denitrification of nitrates and other nitrogen-containing compounds. Nitrogen is oxidized by ozone to NO in the upper atmosphere. Nitrogen N 2 enters into reactions only under specific conditions (for example, during a lightning discharge). Oxidation of molecular nitrogen by ozone during electrical discharges is used in small quantities in the industrial production of nitrogen fertilizers. It can be oxidized with low energy consumption and converted into a biologically active form by cyanobacteria (blue-green algae) and nodule bacteria that form rhizobial symbiosis with legumes, which can be effective green manure plants that do not deplete, but enrich the soil with natural fertilizers.

Oxygen The composition of the atmosphere began to change radically with the advent of living organisms on Earth, as a result of photosynthesis, accompanied by the release of oxygen and the absorption of carbon dioxide. Initially, oxygen was spent on the oxidation of reduced compounds of ammonia, hydrocarbons, the ferrous form of iron contained in the oceans, etc. this stage the oxygen content in the atmosphere began to rise. Gradually, a modern atmosphere with oxidizing properties formed. Since this caused serious and abrupt changes in many processes occurring in the atmosphere, lithosphere and biosphere, this event was called the Oxygen Catastrophe. During the Phanerozoic, the composition of the atmosphere and the oxygen content underwent changes. They correlated primarily with the rate of deposition of organic sedimentary rocks. So, during the periods of coal accumulation, the oxygen content in the atmosphere, apparently, noticeably exceeded the modern level.

Carbon dioxide The content of CO 2 in the atmosphere depends on volcanic activity and chemical processes in the earth's shells, but most of all on the intensity of biosynthesis and decomposition of organic matter in the Earth's biosphere. Almost the entire current biomass of the planet (about 2.4·10 12 tons) is formed due to carbon dioxide, nitrogen and water vapor contained in the atmospheric air. Buried in the ocean, swamps and forests, organic matter turns into coal, oil and natural gas

Noble gases Source of inert gases argon, helium and krypton volcanic eruptions and decay of radioactive elements. The earth as a whole and the atmosphere in particular are depleted in inert gases compared to space. It is believed that the reason for this lies in the continuous leakage of gases into interplanetary space.

Atmospheric pollution B recent times man began to influence the evolution of the atmosphere. result human activity there was a constant increase in the content of carbon dioxide in the atmosphere due to the combustion of hydrocarbon fuels accumulated in previous geological epochs. Huge amounts of CO 2 are consumed during photosynthesis and absorbed by the world's oceans. This gas enters the atmosphere due to the decomposition of carbonate rocks and organic substances of plant and animal origin, as well as due to volcanism and production activities person. Over the past 100 years, the content of CO 2 in the atmosphere has increased by 10%, with the main part (360 billion tons) coming from fuel combustion. If the growth rate of fuel combustion continues, then in the coming years the amount of CO 2 in the atmosphere will double and may lead to global climate change. Fuel combustion is the main source of pollutant gases (CO, NO, SO 2). Sulfur dioxide is oxidized by atmospheric oxygen to SO 3, and nitric oxide to NO 2 in the upper atmosphere, which in turn interact with water vapor, and the resulting sulphuric acid H 2 SO 4 and nitric acid HNO 3 fall on the surface of the Earth in the form of the so-called. acid rain. The use of internal combustion engines leads to significant air pollution with nitrogen oxides, hydrocarbons and lead compounds (tetraethyl lead Pb (CH 3 CH 2) 4). Aerosol pollution of the atmosphere is due to both natural causes (volcanic eruption, dust storms, entrainment of drops of sea water and pollen of plants, etc.), and economic activity human (mining ores and building materials, fuel combustion, cement production, etc.). Intense large-scale removal of particulate matter into the atmosphere is one of the possible causes planetary climate change.