The percentage of oxygen in the earth's atmosphere is. Vertical structure of the atmosphere
Space is filled with energy. Energy fills space unevenly. There are places of its concentration and discharge. This way you can estimate the density. The planet is an ordered system, with the maximum density of matter in the center and with a gradual decrease in concentration towards the periphery. Interaction forces determine the state of matter, the form in which it exists. Physics describes the aggregate state of substances: solid, liquid, gas and so on.
The atmosphere is the gaseous medium that surrounds the planet. The Earth's atmosphere allows free movement and allows light to pass through, creating a space in which life thrives.
The area from the earth's surface to a height of approximately 16 kilometers (from the equator to the poles, a smaller value, also depends on the season) is called the troposphere. The troposphere is the layer that contains about 80% of the air in the atmosphere and almost all of the water vapor. It is here that the processes that shape the weather take place. Pressure and temperature decrease with height. The reason for the decrease in air temperature is an adiabatic process, when the gas expands, it cools. At the upper boundary of the troposphere, values can reach -50, -60 degrees Celsius.
Next comes the Stratosphere. It extends up to 50 kilometers. In this layer of the atmosphere, the temperature increases with height, acquiring a value at the top point of about 0 C. The temperature increase is caused by the process of absorption of ultraviolet rays by the ozone layer. Radiation causes a chemical reaction. Oxygen molecules break down into single atoms that can combine with normal oxygen molecules to form ozone.
Radiation from the sun with wavelengths between 10 and 400 nanometers is classified as ultraviolet. The shorter the wavelength of UV radiation, the greater the danger it poses to living organisms. Only a small fraction of the radiation reaches the Earth's surface, moreover, the less active part of its spectrum. This feature of nature allows a person to get a healthy sun tan.
The next layer of the atmosphere is called the Mesosphere. Limits from approximately 50 km to 85 km. In the mesosphere, the concentration of ozone, which could trap UV energy, is low, so the temperature begins to fall again with height. At the peak point, the temperature drops to -90 C, some sources indicate a value of -130 C. Most meteoroids burn up in this layer of the atmosphere.
The layer of the atmosphere that stretches from a height of 85 km to a distance of 600 km from the Earth is called the Thermosphere. The thermosphere is the first to encounter solar radiation, including the so-called vacuum ultraviolet.
Vacuum UV is delayed by the air, thereby heating this layer of the atmosphere to enormous temperatures. However, since the pressure here is extremely low, this seemingly incandescent gas does not have the same effect on objects as it does under conditions on the earth's surface. On the contrary, objects placed in such an environment will cool down.
At an altitude of 100 km, the conditional line "Karman line" passes, which is considered to be the beginning of space.
Auroras occur in the thermosphere. In this layer of the atmosphere, the solar wind interacts with the planet's magnetic field.
The last layer of the atmosphere is the Exosphere, an outer shell that stretches for thousands of kilometers. The exosphere is practically an empty place, however, the number of atoms wandering here is an order of magnitude greater than in interplanetary space.
The person breathes air. normal pressure- 760 millimeters of mercury. At an altitude of 10,000 m, the pressure is about 200 mm. rt. Art. At this altitude, a person can probably breathe, at least not for a long time, but this requires preparation. The state will obviously be inoperable.
The gas composition of the atmosphere: 78% nitrogen, 21% oxygen, about a percent argon, everything else is a mixture of gases representing the smallest fraction of the total.
The atmosphere is what makes life possible on Earth. We receive the very first information and facts about the atmosphere back in primary school. In high school, we are already more familiar with this concept in geography lessons.
The concept of the earth's atmosphere
The atmosphere is not only on the Earth, but also on other celestial bodies. That's what they call gas envelope surrounding the planets. The composition of this gas layer of different planets is significantly different. Let's look at the basic information and facts about otherwise called air.
Its most important component is oxygen. Some mistakenly think that the earth's atmosphere is made entirely of oxygen, but air is actually a mixture of gases. It contains 78% nitrogen and 21% oxygen. The remaining one percent includes ozone, argon, carbon dioxide, water vapor. Let the percentage of these gases be small, but they perform an important function - they absorb a significant part of the solar radiant energy, thereby preventing the luminary from turning all life on our planet into ashes. The properties of the atmosphere change with altitude. For example, at an altitude of 65 km, nitrogen is 86% and oxygen is 19%.
The composition of the Earth's atmosphere
- Carbon dioxide essential for plant nutrition. In the atmosphere, it appears as a result of the process of respiration of living organisms, rotting, burning. The absence of it in the composition of the atmosphere would make it impossible for any plants to exist.
- Oxygen is a vital component of the atmosphere for humans. Its presence is a condition for the existence of all living organisms. It makes up about 20% of the total atmospheric gases.
- Ozone is a natural solar absorber ultraviolet radiation which adversely affects living organisms. Most of it forms a separate layer of the atmosphere - the ozone screen. Recently, human activity has led to the fact that it begins to gradually collapse, but since it is of great importance, it is being active work for its conservation and restoration.
- water vapor determines the humidity of the air. Its content may vary depending on various factors: air temperature, geographical location, season. At low temperatures, there is very little water vapor in the air, maybe less than one percent, and at high temperatures, its amount reaches 4%.
- In addition to all of the above, in the composition of the earth's atmosphere there is always a certain percentage solid and liquid impurities. It's soot, ashes sea salt, dust, water drops, microorganisms. They can get into the air both naturally and by anthropogenic means.
Layers of the atmosphere
temperature, density, and qualitative composition air is not the same at different heights. Because of this, it is customary to distinguish different layers of the atmosphere. Each of them has its own characteristic. Let's find out which layers of the atmosphere are distinguished:
- The troposphere is the layer of the atmosphere closest to the Earth's surface. Its height is 8-10 km above the poles and 16-18 km in the tropics. Here is 90% of all water vapor that is available in the atmosphere, so there is active education clouds. Also in this layer there are such processes as the movement of air (wind), turbulence, convection. The temperature ranges from +45 degrees at noon in the warm season in the tropics to -65 degrees at the poles.
- The stratosphere is the second furthest layer from the atmosphere. It is located at an altitude of 11 to 50 km. In the lower layer of the stratosphere, the temperature is approximately -55, towards the distance from the Earth it rises to +1˚С. This region is called the inversion and is the boundary between the stratosphere and the mesosphere.
- The mesosphere is located at an altitude of 50 to 90 km. The temperature at its lower boundary is about 0, at the upper it reaches -80...-90 ˚С. Meteorites entering the Earth's atmosphere burn out completely in the mesosphere, which causes airglows to occur here.
- The thermosphere is about 700 km thick. The northern lights appear in this layer of the atmosphere. They appear due to the action of cosmic radiation and radiation emanating from the Sun.
- The exosphere is a zone of air dispersion. Here, the concentration of gases is small and their gradual escape into interplanetary space takes place.
The boundary between the earth's atmosphere and outer space is considered to be a line of 100 km. This line is called the Karman line.
atmospheric pressure
Listening to the weather forecast, we often hear barometric pressure readings. But what does atmospheric pressure mean, and how might it affect us?
We figured out that air consists of gases and impurities. Each of these components has its own weight, which means that the atmosphere is not weightless, as was believed until the 17th century. Atmospheric pressure is the force with which all layers of the atmosphere press on the surface of the Earth and on all objects.
Scientists have carried out complex calculations and proved that for one square meter area, the atmosphere presses with a force of 10,333 kg. Means, human body subject to air pressure, the weight of which is 12-15 tons. Why don't we feel it? It saves us its internal pressure, which balances the external one. You can feel the pressure of the atmosphere while on an airplane or high in the mountains, as Atmosphere pressure much less at altitude. In this case, physical discomfort, stuffy ears, dizziness are possible.
A lot can be said about the atmosphere around. We know a lot about her. interesting facts, and some of them may seem surprising:
- The weight of the earth's atmosphere is 5,300,000,000,000,000 tons.
- It contributes to the transmission of sound. At an altitude of more than 100 km, this property disappears due to changes in the composition of the atmosphere.
- The movement of the atmosphere is provoked uneven heating the surface of the earth.
- A thermometer is used to measure air temperature, and a barometer is used to measure atmospheric pressure.
- The presence of an atmosphere saves our planet from 100 tons of meteorites daily.
- The composition of the air was fixed for several hundred million years, but began to change with the onset of rapid industrial activity.
- It is believed that the atmosphere extends upwards to an altitude of 3000 km.
The value of the atmosphere for humans
The physiological zone of the atmosphere is 5 km. At an altitude of 5000 m above sea level, a person begins to manifest oxygen starvation, which is expressed in a decrease in its performance and deterioration of well-being. This shows that a person cannot survive in a space where this amazing mixture of gases does not exist.
All information and facts about the atmosphere only confirm its importance for people. Thanks to its presence, the possibility of the development of life on Earth appeared. Even today, having assessed the extent of the harm that mankind is capable of inflicting with its actions on the life-giving air, we should think about further measures to preserve and restore the atmosphere.
The air shell that surrounds our planet and rotates with it is called the atmosphere. Half of the total mass of the atmosphere is concentrated in the lower 5 km, and three-quarters of the mass in the lower 10 km. Above, the air is much rarefied, although its particles are found at an altitude of 2000-3000 km above the earth's surface.
The air we breathe is a mixture of gases. Most of all it contains nitrogen - 78% and oxygen - 21%. Argon is less than 1% and 0.03% is carbon dioxide. Numerous other gases, such as krypton, xenon, neon, helium, hydrogen, ozone and others, make up thousandths and millionths of a percent. The air also contains water vapor, particles of various substances, bacteria, pollen and cosmic dust.
The atmosphere is made up of several layers. The lower layer up to a height of 10-15 km above the Earth's surface is called the troposphere. It heats up from the Earth, so the air temperature here with height drops by 6 ° C per 1 kilometer of ascent. Almost all water vapor is in the troposphere and almost all clouds are formed - note .. The height of the troposphere over different latitudes of the planet is not the same. It rises up to 9 km above the poles, up to 10-12 km over temperate latitudes, and up to 15 km over the equator. The processes occurring in the troposphere - the formation and movement of air masses, the formation of cyclones and anticyclones, the appearance of clouds and precipitation - determine the weather and climate near the earth's surface.
Above the troposphere is the stratosphere, which extends up to 50-55 km. The troposphere and stratosphere are separated by a transition layer called the tropopause, 1–2 km thick. In the stratosphere at an altitude of about 25 km, the air temperature gradually begins to rise and reaches + 10 +30 °С at 50 km. Such an increase in temperature is due to the fact that there is a layer of ozone in the stratosphere at altitudes of 25-30 km. At the surface of the Earth, its content in the air is negligible, and at high altitudes, diatomic oxygen molecules absorb ultraviolet solar radiation, forming triatomic ozone molecules.
If ozone were located in the lower layers of the atmosphere, at a height with normal pressure, the thickness of its layer would be only 3 mm. But even in such a small amount, it plays a very important role: it absorbs part of the solar radiation harmful to living organisms.
Above the stratosphere, up to about 80 km, the mesosphere extends, in which the air temperature drops with height to several tens of degrees below zero.
The upper part of the atmosphere is very high temperatures and is called the thermosphere - note .. It is divided into two parts - the ionosphere - up to a height of about 1000 km, where the air is highly ionized, and the exosphere - over 1000 km. In the ionosphere, atmospheric gas molecules absorb ultraviolet radiation from the Sun, and charged atoms and free electrons are formed. Auroras are observed in the ionosphere.
The atmosphere plays a very important role in the life of our planet. It protects the Earth from strong heating by the sun's rays during the day and from hypothermia at night. Most meteorites burn up in the atmospheric layers before reaching the surface of the planet. The atmosphere contains oxygen, necessary for all organisms, an ozone shield that protects life on Earth from the harmful part of the ultraviolet radiation of the Sun.
ATMOSPHERES OF THE PLANETS OF THE SOLAR SYSTEM
The atmosphere of Mercury is so rarefied that, one might say, it is practically non-existent. The air envelope of Venus consists of carbon dioxide (96%) and nitrogen (about 4%), it is very dense - the atmospheric pressure near the surface of the planet is almost 100 times greater than on Earth. The Martian atmosphere also consists mainly of carbon dioxide (95%) and nitrogen (2.7%), but its density is about 300 times less than that of the earth, and its pressure is almost 100 times less. The apparent surface of Jupiter is actually upper layer hydrogen-helium atmosphere. The air shells of Saturn and Uranus are the same in composition. The beautiful blue color of Uranus is due to the high concentration of methane in the upper part of its atmosphere - approx .. Neptune, shrouded in hydrocarbon haze, has two main layers of clouds: one consists of frozen methane crystals, and the second, located below, contains ammonia and hydrogen sulfide.
- air shell the globe rotating with the earth. The upper boundary of the atmosphere is conventionally carried out at altitudes of 150-200 km. The lower boundary is the surface of the Earth.
Atmospheric air is a mixture of gases. Most of its volume in the surface air layer is nitrogen (78%) and oxygen (21%). In addition, the air contains inert gases (argon, helium, neon, etc.), carbon dioxide (0.03), water vapor, and various solid particles (dust, soot, salt crystals).
The air is colorless, and the color of the sky is explained by the peculiarities of the scattering of light waves.
The atmosphere consists of several layers: troposphere, stratosphere, mesosphere and thermosphere.
The bottom layer of air is called troposphere. At different latitudes, its power is not the same. The troposphere repeats the shape of the planet and participates together with the Earth in axial rotation. At the equator, the thickness of the atmosphere varies from 10 to 20 km. At the equator it is greater, and at the poles it is less. The troposphere is characterized by the maximum density of air, 4/5 of the mass of the entire atmosphere is concentrated in it. The troposphere determines weather: various air masses are formed here, clouds and precipitation are formed, there is an intensive horizontal and vertical movement of air.
Above the troposphere, up to an altitude of 50 km, is located stratosphere. It is characterized by a lower density of air, there is no water vapor in it. In the lower part of the stratosphere at altitudes of about 25 km. there is an "ozone screen" - a layer of the atmosphere with a high concentration of ozone, which absorbs ultraviolet radiation, which is fatal to organisms.
At an altitude of 50 to 80-90 km extends mesosphere. As the altitude increases, the temperature decreases with an average vertical gradient of (0.25-0.3)° / 100 m, and the air density decreases. The main energy process is radiant heat transfer. The glow of the atmosphere is due to complex photochemical processes involving radicals, vibrationally excited molecules.
Thermosphere located at an altitude of 80-90 to 800 km. The air density here is minimal, the degree of air ionization is very high. The temperature changes depending on the activity of the Sun. In connection with big amount charged particles here are observed polar lights and magnetic storms.
The atmosphere is of great importance for the nature of the Earth. Without oxygen, living organisms cannot breathe. Its ozone layer protects all living things from harmful ultraviolet rays. The atmosphere smooths out temperature fluctuations: the Earth's surface does not get supercooled at night and does not overheat during the day. In dense layers atmospheric air before reaching the surface of the planet, meteorites burn from thorns.
The atmosphere interacts with all the shells of the earth. With its help, the exchange of heat and moisture between the ocean and land. Without the atmosphere there would be no clouds, precipitation, winds.
Human activities have a significant adverse effect on the atmosphere. Air pollution occurs, which leads to an increase in the concentration of carbon monoxide (CO 2). And this contributes global warming climate and amplifies the greenhouse effect. The ozone layer of the Earth is being destroyed due to industrial waste and transport.
The atmosphere needs to be protected. In developed countries, a set of measures is being taken to protect atmospheric air from pollution.
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The composition of the atmosphere. The air shell of our planet - atmosphere protects the earth's surface from the harmful effects on living organisms of ultraviolet radiation from the Sun. It also protects the Earth from cosmic particles - dust and meteorites.
The atmosphere consists of a mechanical mixture of gases: 78% of its volume is nitrogen, 21% is oxygen, and less than 1% is helium, argon, krypton and other inert gases. The amount of oxygen and nitrogen in the air is practically unchanged, because nitrogen almost does not enter into compounds with other substances, and oxygen, which, although very active and is spent on respiration, oxidation and combustion, is constantly replenished by plants.
Up to a height of about 100 km, the percentage of these gases remains practically unchanged. This is due to the fact that the air is constantly mixed.
In addition to these gases, the atmosphere contains about 0.03% carbon dioxide, which is usually concentrated near the earth's surface and is distributed unevenly: in cities, industrial centers and areas of volcanic activity, its amount increases.
There is always a certain amount of impurities in the atmosphere - water vapor and dust. The content of water vapor depends on the temperature of the air: the higher the temperature, the more vapor the air holds. Due to the presence of vaporous water in the air, atmospheric phenomena such as rainbows, refraction of sunlight, etc. are possible.
Dust enters the atmosphere during volcanic eruptions, sand and dust storms, with incomplete combustion of fuel at thermal power plants, etc.
The structure of the atmosphere. The density of the atmosphere changes with height: it is highest at the Earth's surface, and decreases as it rises. So, at an altitude of 5.5 km, the density of the atmosphere is 2 times, and at an altitude of 11 km - 4 times less than in the surface layer.
Depending on the density, composition and properties of gases, the atmosphere is divided into five concentric layers (Fig. 34).
Rice. 34. Vertical section of the atmosphere (atmospheric stratification)
1. The bottom layer is called troposphere. Its upper boundary runs at an altitude of 8-10 km at the poles and 16-18 km at the equator. The troposphere contains up to 80% of the total mass of the atmosphere and almost all of the water vapor.
The air temperature in the troposphere decreases with height by 0.6 °C every 100 m and at its upper boundary it is -45-55 °C.
Air in the troposphere is constantly churning different directions. Only here fogs, rains, snowfalls, thunderstorms, storms and other weather phenomena are observed.
2. Above is located stratosphere, which extends to a height of 50-55 km. Air density and pressure in the stratosphere are negligible. The rarefied air consists of the same gases as in the troposphere, but it contains more ozone. The highest concentration of ozone is observed at an altitude of 15-30 km. The temperature in the stratosphere rises with height and reaches 0 °C or more at its upper boundary. This is because ozone absorbs the short wavelength. solar energy, causing the air to heat up.
3. Above the stratosphere lies mesosphere, extending to a height of 80 km. In it, the temperature drops again and reaches -90 ° C. The air density there is 200 times less than at the surface of the Earth.
4. Above the mesosphere is thermosphere(from 80 to 800 km). The temperature in this layer rises: at an altitude of 150 km to 220 °C; at an altitude of 600 km to 1500 °C. The atmospheric gases (nitrogen and oxygen) are in an ionized state. Under the action of short-wave solar radiation, individual electrons are detached from the shells of atoms. As a result, in this layer - ionosphere layers of charged particles appear. Their densest layer is at an altitude of 300-400 km. Due to the low density Sun rays they do not scatter there, so the sky is black, stars and planets shine brightly on it.
In the ionosphere there are polar lights, powerful electric currents that cause disturbance magnetic field Earth.
5. Above 800 km, the outer shell is located - exosphere. The speed of movement of individual particles in the exosphere approaches the critical one - 11.2 mm/s, so individual particles can overcome the Earth's gravity and escape into the world space.
The value of the atmosphere. The role of the atmosphere in the life of our planet is exceptionally great. Without it, the Earth would be dead. The atmosphere protects the Earth's surface from intense heating and cooling. Its influence can be likened to the role of glass in greenhouses: to let in the sun's rays and prevent heat from escaping.
The atmosphere protects living organisms from the shortwave and corpuscular radiation of the Sun. The atmosphere is the environment where weather phenomena occur, with which all human activity. The study of this shell is carried out at meteorological stations. Day and night, in any weather, meteorologists monitor the state of the lower atmosphere. Four times a day, and at many stations every hour they measure temperature, pressure, air humidity, note cloudiness, wind direction and speed, precipitation, electrical and sound phenomena in the atmosphere. Weather stations located everywhere: in Antarctica and in tropical rainforests, on high mountains and in the boundless expanses of the tundra. Observations are also being made on the oceans from specially built ships.
From the 30s. 20th century observations began in the free atmosphere. They began to launch radiosondes, which rise to a height of 25-35 km, and with the help of radio equipment transmit to Earth information about temperature, pressure, air humidity and wind speed. Nowadays, meteorological rockets and satellites are also widely used. The latter have television installations that transmit images of the earth's surface and clouds.
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5. Air shell of the earth§ 31. Heating of the atmosphere
