That part of the atmosphere that is adjacent to the Earth and which a person breathes accordingly is called the troposphere. The troposphere has a height of nine to eleven kilometers and is a mechanical mixture of various gases.

The composition of the air is not constant. Depending on the geographical location, terrain, weather conditions, air can have different composition and different properties. The air can be polluted or rarefied, fresh or heavy - all this means that it contains certain impurities.

Nitrogen - 78.9 percent;

Oxygen - 20.95 percent;

Carbon dioxide - 0.3 percent.

In addition, other gases are present in the atmosphere (helium, argon, neon, xenon, krypton, hydrogen, radon, ozone), and their total amount is slightly less than one percent.

It is also worth pointing out the presence in the air of some permanent impurities of natural origin, in particular, some gaseous products that are formed as a result of both biological and chemical processes. Among them, ammonia deserves special mention (the composition of the air far from populated areas includes about three to five thousandths of a milligram per cubic meter), methane (its level is on average two ten thousandths of a milligram per cubic meter), nitrogen oxides (in the atmosphere their concentration reaches approximately fifteen ten-thousandths of a milligram per cubic meter), hydrogen sulfide and other gaseous products.

In addition to vapor and gaseous impurities, the chemical composition of the air usually includes dust of cosmic origin, which falls on the Earth's surface in the amount of seven hundred thousandths of a ton per square kilometer during the year, as well as dust particles that come from volcanic eruptions.

However, it changes to the greatest extent (and not in better side) the composition of the air and pollutes the troposphere by the so-called ground (plant, soil) dust and smoke of forest fires. There is especially a lot of such dust in continental air masses originating in the deserts of Central Asia and Africa. That is why we can say with confidence that an ideally clean air environment simply does not exist, and it is a concept that exists only theoretically.

The composition of air tends to constantly change, and its natural changes usually play a fairly small role, especially in comparison with the possible consequences of its artificial disturbances. Such disruptions are predominantly associated with human production activities, the use of consumer services devices, and vehicles. These disturbances can lead, among other things, to air denaturation, that is, to pronounced differences in its composition and properties from the corresponding indicators of the atmosphere.

These and many other types of human activity have led to the fact that the basic composition of the air began to undergo slow and insignificant, but nevertheless absolutely irreversible changes. For example, scientists have calculated that over the past fifty years, humanity has used approximately the same amount of oxygen as in the previous million years, and in percentage terms - two-tenths of a percent of its total supply in the atmosphere. At the same time, emissions into the air increase accordingly. According to the latest data, emissions have reached almost four hundred billion tons over the past hundred years.

Thus, the composition of the air is changing for the worse, and it is difficult to imagine what it will be like in a few decades.

Air is a mixture of gases, consisting of 78% nitrogen, 21% oxygen, relatively little carbon dioxide, and also water vapor.

Air is necessary for breathing for all living organisms: humans, animals, plants.

The ocean of air surrounds our planet, fills all the voids on earth, and is found in water in dissolved form.

The uneven heating of air above the Earth's surface moves air masses and causes wind. Warm, lighter air rises above land or sea, cold, heavier air sinks down from the upper layers. This affects the climate of many areas.

1. meaning of air on earth
2. properties of air
3. air composition
4. air protection
5. amazing winds

The meaning of air on earth

• Air is necessary for breathing for all living organisms.
• The movement of air masses associated with uneven heating at the Earth's surface determines climatic features in different regions. It is the winds that bring from the oceans all the masses of water that feed the rivers and give life to living nature.
• Many properties of air are used in the everyday life of people and animals.
• Sound transmission over a distance occurs through air. Sound is vibrations in the air that are picked up by the ear. The most enormous cosmic disasters, such as the explosion of a star, take place completely silently, in perfect silence. We can experience the pleasure of hearing sound only on Earth, where there is atmospheric air.

Properties air

Airplane flight, balloons, the movement of a sailboat and a wind power plant, the soaring of birds, the operation of a vacuum cleaner - all this occurs due to the properties of the air.

Air elasticity, that is, the ability of air to restore its previous volume after the pressure on it ceases - car tires, a ball, an air pistol. Compressibility characterizes the property of air to change its volume and density with changes in pressure and temperature.

Low thermal conductivity of air and used, for example, in double window frames. Glass by itself does not protect against cold; it only retains air, which is a poor conductor of heat. And the apartment maintains the desired temperature.

Air is transparent and invisible, odorless, has no definite volume, has a mass lighter than water, warm air is lighter than cold air, and rises upward. Man has learned to use many properties in science and technology.

Compound air

Air consists of 1/5 oxygen, 4/5 nitrogen, and no more than 1% is the rest of the gases, including carbon dioxide. Contains air and water vapor.

It is oxygen that animals and humans need. Carbon dioxide CO 2 is consumed by plants and produces oxygen. Therefore, the composition of the air is different in a forest or in a city. In the city there is less oxygen, more carbon dioxide, in the forest - vice versa. Forests are called the “lungs” of our planet.

Air protection

Human industrial activities lead to pollution environment. Humanity burns oil, gas, gasoline, coal and other types of fuel in the furnaces of power plants, various factories, and in car engines. When fuel burns incompletely, particles of harmful substances enter the air. They are carried with air masses by winds all over the world and, together with precipitation, return to the earth, polluting water, soil and all the nature around us.

Air pollution leads to the greenhouse effect. The surface of the globe is gradually warming up. Glaciers at the poles are melting, the level of the world's oceans is rising. More and more disasters are befalling humanity. In order to live comfortably in the future, a person must take care of protecting the cleanliness of the air by reducing emissions from industrial enterprises and cars. This is a question of the existence of a bright future.

Amazing winds

Wind is one of the most common natural phenomena. Familiar and understandable to everyone. Sometimes pleasant, sometimes unpleasant.

What is wind? Where the air is hotter, it rises; colder, heavier air sinks. We say: the wind blows.

It also happens: sand dunes sing mysterious songs. The poisonous breath of a sandstorm poisons all living things.

The wind is blowing, and a huge whirlwind is rushing over the earth - a tornado. A tropical storm leaves behind a heavy picture of destruction.

Tornado is the name given to a tornado of gigantic destructive power in North America. These whirlwinds destroy everything in their path.

“During the lesson,” says the teacher! one of the American schools - I heard a deafening roar. The wind blew suddenly with monstrous force. Before I had time to take the children to safety, all the glass in the school blew out. The children rushed to me. But then, as if invisible wings, they were picked up by various objects that were in the classroom. We all rose into the air. Children and the wreckage of the school were swirling around me.”

When a tornado moves along the ground, it resembles a huge vacuum cleaner - everything that comes along the way is sucked into the funnel. When wind passes through bodies of water, the bottom is often exposed.

There are such tornadoes in our country, it’s true, but they are so fierce, but also strong. Several years ago, at a crossing near Moscow railway the wind lifted the railway box high into the air. She was thrown to the ground forty meters from the old place. The lineman who was in it remained alive. And all this happened in a matter of minutes. Roofs torn off houses flew in the air, as if they had suddenly miraculously become weightless. Where the tornado crossed the Moscow River, its bottom was exposed. A formidable whirlwind passed about forty kilometers, destroying several villages near Moscow along the way.

Why do tornadoes form?

There is still a lot hidden by nature. It is known that they are formed in a thundercloud, where powerful flows of moist warm and cold air collide and move. A heavy downpour falls from the cloud, and the whirlwind captures and spins more and more new streams, forming a huge funnel.

A hurricane at sea is very dangerous. Several years ago, American scientists on a cruiser tried to get into the center of the hurricane to see for themselves what was happening there. This attempt ended tragically. The last report from researchers was that the waves in the center of the typhoon reached a height of 40 meters and raged with monstrous force. Currently, many useful discoveries have been made by typhoon hunter pilots. Their main task is to notify about the danger, where the typhoon is, what its strength is, where it is moving.

Download a report on the topic of air for grades 2 - 3 on the subject of the world around us

Our planet is enveloped in a shell of air - the atmosphere. Thanks to it, life became possible on the globe, because all living beings - people, plants, animals - need air. It contains not only oxygen, but also many other elements that are also of great importance.

What is air?

Air is a mixture of various gases: oxygen, nitrogen, carbon dioxide, argon and water vapor. However, the most important component of air, without which life on the planet would be impossible, is oxygen.

The composition of air is influenced by two main factors:

• Height above sea level. As you climb the mountain, the amount of oxygen in the air will decrease more and more.
• Features of the area. In large cities, the amount of carbon dioxide is much higher than in a clean forest.

Rice. 1. The air in the forest is the cleanest.

Clean air is colorless and odorless.

One of the most serious environmental problems modern world is air pollution. A large number of cars, factories and factories greatly pollute the atmosphere with toxic substances. People living in cities are forced to breathe this poisonous gas. To solve this problem, it is necessary to introduce powerful treatment facilities into production.

Rice. 2. Air pollution.

What is air needed for?

An ocean of air surrounds the Earth, filling the voids and the tiniest crevices. It is even found in water, only in dissolved form.

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Air performs very important functions:

• All living organisms need air to breathe. Thanks to the respiratory processes, the body of people and animals is saturated with energy and nutrients, and all vital processes are activated. Without air, plants would not be able to breathe and form nutrients.

A person can live without food for several weeks, without water for several days, and without air for only a few minutes. If you try not to breathe for some time, then within a few seconds you will have a strong desire to take a deep breath. Without air there is no life!

• Air movement, which is associated with uneven heating, determines the climate in different regions. Land areas far from the seas and oceans are saturated with moisture brought by the winds.

Rice. 3. Formation of clouds and clouds.

• The vast air space provides reliable protection from dangerous solar radiation and cosmic cold.
• Thanks to air, we can make and hear sounds. Sound is a wave that can be transmitted over a distance only under atmospheric conditions. For example, there is no atmosphere on the Moon, and absolute silence reigns there.

The air “blanket” is held in place by the forces of gravity. If for some reason the globe was left without an atmosphere, it would very quickly turn into a lifeless desert.

What have we learned?

When studying the topic “Air” according to the 3rd grade program of the world around us, we learned what air is and what is included in its composition. We also found out what functions it performs and what role it plays for all life on Earth.

Test on the topic

Evaluation of the report

Average rating: 4.6. Total ratings received: 363.

It has important in the implementation of respiratory function. Atmospheric air is a mixture of gases: oxygen, carbon dioxide, argon, nitrogen, neon, krypton, xenon, hydrogen, ozone, etc. Oxygen is the most important. At rest, a person absorbs 0.3 l/min. During physical activity, oxygen consumption increases and can reach 4.5–8 l/min. Fluctuations in the oxygen content in the atmosphere are small and do not exceed 0.5%. If the oxygen content decreases to 11-13%, symptoms of oxygen deficiency appear. Oxygen content of 7-8% can lead to death. Carbon dioxide is colorless and odorless, formed during respiration and decay, combustion of fuel. In the atmosphere it is 0.04%, and in industrial zones – 0.05-0.06%. With a large crowd of people it can increase to 0.6 - 0.8%. With prolonged inhalation of air containing 1-1.5% carbon dioxide, a deterioration in health is noted, and with 2-2.5% - pathological changes. At 8-10% loss of consciousness and death, the air has a pressure called atmospheric or barometric. It is measured in millimeters of mercury (mmHg), hectopascals (hPa), millibars (mb). Normal atmospheric pressure is considered to be at sea level at a latitude of 45˚ at an air temperature of 0˚C. It is equal to 760 mmHg. (The air in a room is considered to be of poor quality if it contains 1% carbon dioxide. This value is accepted as a calculated value when designing and installing ventilation in rooms.

Air pollution. Carbon monoxide is a colorless and odorless gas that is formed during incomplete combustion of fuel and enters the atmosphere with industrial emissions and exhaust gases from internal combustion engines. In megacities, its concentration can reach 50-200 mg/m3. When smoking tobacco, carbon monoxide enters the body. Carbon monoxide is a blood and general toxic poison. It blocks hemoglobin, it loses its ability to carry oxygen to tissues. Acute poisoning occurs when the concentration of carbon monoxide in the air is 200-500 mg/m3. At the same time, it is observed headache, general weakness, nausea, vomiting. The maximum permissible average daily concentration is 0 1 mg/m3, one-time – 6 mg/m3. The air can be polluted by sulfur dioxide, soot, tarry substances, nitrogen oxides, and carbon disulfide.

Microorganisms. They are always found in small quantities in the air, where they are carried with soil dust. Microbes released into the atmosphere infectious diseases die quickly. The air in residential premises and sports facilities poses a particular danger in terms of epidemiology. For example, in wrestling halls there is a microbial content of up to 26,000 per 1m3 of air. Aerogenic infections spread very quickly in such air.

Dust It is light dense particles of mineral or organic origin; when dust gets into the lungs, it lingers there and causes various diseases. Industrial dust (lead, chrome) can cause poisoning. In cities, dust should not exceed 0.15 mg/m3. Sports grounds must be regularly watered, have a green area, and be wet cleaned. Sanitary protection zones have been established for all enterprises that pollute the atmosphere. In accordance with the hazard class, they have different sizes: for enterprises of class 1 - 1000 m, 2 - 500 m, 3 - 300 m, 4 -100 m, 5 - 50 m. When placing sports facilities near enterprises, it is necessary to take into account the wind rose, sanitary protective zones, degree of air pollution, etc.

One of the important measures to protect the air environment is preventive and ongoing sanitary supervision and systematic monitoring of the state of atmospheric air. It is carried out using an automated monitoring system.

Clean atmospheric air at the surface of the Earth has the following chemical composition: oxygen - 20.93%, carbon dioxide - 0.03-0.04%, nitrogen - 78.1%, argon, helium, krypton 1%.

The exhaled air contains 25% less oxygen and 100 times more carbon dioxide.
Oxygen. The most important component of air. It ensures the flow of redox processes in the body. An adult consumes 12 liters of oxygen at rest, and 10 times more during physical work. In the blood, oxygen is bound to hemoglobin.

Ozone. A chemically unstable gas, it is capable of absorbing solar short-wave ultraviolet radiation, which has a detrimental effect on all living things. Ozone absorbs long-wave infrared radiation emanating from the Earth, and thereby prevents its excessive cooling (Earth's ozone layer). Under the influence of ultraviolet radiation, ozone decomposes into an oxygen molecule and an atom. Ozone is a bactericidal agent for water disinfection. In nature, it is formed during electrical discharges, during the evaporation of water, during ultraviolet radiation, during a thunderstorm, in the mountains and in coniferous forests.

Carbon dioxide. It is formed as a result of redox processes occurring in the body of people and animals, combustion of fuel, and decay of organic substances. In the air of cities, the concentration of carbon dioxide is increased due to industrial emissions - up to 0.045%, in residential premises - up to 0.6-0.85. An adult at rest emits 22 liters of carbon dioxide per hour, and during physical work - 2-3 times more. Signs of deterioration in a person’s well-being appear only with prolonged inhalation of air containing 1-1.5% carbon dioxide, pronounced functional changes - at a concentration of 2-2.5% and sharply severe symptoms(headache, general weakness, shortness of breath, palpitations, decreased performance) – at 3-4%. The hygienic importance of carbon dioxide lies in the fact that it serves as an indirect indicator of general air pollution. The carbon dioxide standard in gyms is 0.1%.

Nitrogen. An indifferent gas serves as a diluent for other gases. Increased inhalation of nitrogen can have a narcotic effect.

Carbon monoxide. Formed during incomplete combustion of organic substances. It has neither color nor smell. The concentration in the atmosphere depends on the intensity of vehicle traffic. Penetrating through the pulmonary alveoli into the blood, it forms carboxyhemoglobin, as a result of which hemoglobin loses its ability to carry oxygen. The maximum permissible average daily concentration of carbon monoxide is 1 mg/m3. Toxic doses of carbon monoxide in the air are 0.25-0.5 mg/l. With prolonged exposure, headache, fainting, palpitations.

Sulphur dioxide. It enters the atmosphere as a result of burning fuels rich in sulfur ( coal). It is formed during the roasting and smelting of sulfur ores and during the dyeing of fabrics. It irritates the mucous membranes of the eyes and upper respiratory tract. The sensation threshold is 0.002-0.003 mg/l. The gas has a harmful effect on vegetation, especially coniferous trees.
Mechanical air impurities come in the form of smoke, soot, soot, crushed soil particles and other solids. Air dust content depends on the nature of the soil (sand, clay, asphalt), its sanitary condition (watering, cleaning), air pollution from industrial emissions, and the sanitary condition of the premises.

Dust mechanically irritates the mucous membranes of the upper respiratory tract and eyes. Systematic inhalation of dust causes respiratory diseases. When breathing through the nose, up to 40-50% of dust is retained. Microscopic dust that remains suspended for a long time is the most unfavorable from a hygienic point of view. The electrical charge of dust enhances its ability to penetrate and linger in the lungs. Dust. containing lead, arsenic, chromium and other toxic substances, causes typical poisoning phenomena, and when penetrated not only by inhalation, but also through the skin and gastrointestinal tract. In dusty air, the intensity of solar radiation and air ionization are significantly reduced. To prevent the adverse effects of dust on the body, residential buildings are located on the windward side of air pollutants. Sanitary protection zones with a width of 50-1000 m or more are arranged between them. In residential premises, systematic wet cleaning, ventilation of rooms, change of shoes and outerwear, in open areas the use of dust-free soils and watering.

Air microorganisms. Bacterial pollution of air, as well as other environmental objects (water, soil), poses an epidemiological danger. There are various microorganisms in the air: bacteria, viruses, molds, yeast cells. The most common is the airborne method of transmission of infections: a large number of microbes enter the air and enter the air when inhaled. Airways healthy people. For example, during a loud conversation, and even more so when coughing and sneezing, tiny droplets are sprayed over a distance of 1-1.5 m and spread with air over 8-9 m. These droplets can be suspended for 4-5 hours, but in most cases settle in 40-60 minutes. In dust, the influenza virus and diphtheria bacilli remain viable for 120-150 days. There is a well-known relationship: the more dust there is in indoor air, the more abundant the microflora content in it.

In this lesson we will learn Interesting Facts about air and its properties.

Theme: Nature

Air is everywhere - on the street, in the room, in the ground, in the water. Any free space on our planet is naturally filled with air. Air is invisible, but it can be detected with the help of the senses. Wind is the movement of air. The layer of air that surrounds our planet is called the atmosphere.

Atmosphere is a giant air shell that extends upward for hundreds of kilometers.

Air is a gas, or rather, a mixture of gases: nitrogen, oxygen and carbon dioxide. The most important of them is oxygen, because that is what a person breathes.

Air has its own properties. The air is transparent, although in reality only clean air is transparent. For example, the smoke of a fire pollutes the air with particles of burning and dust, and then it becomes opaque.

The air should be clean, but in many places, especially in cities, it is polluted.

Rice. 3. Air pollution in cities ()

Factories and plants pollute the air a lot; they emit toxic gases, soot, and dust into the atmosphere. Exhaust gases from cars also pollute the air we breathe, and this is very harmful to human health.

Rice. 4. Air pollution from exhaust gases ()

Air pollution threatens human health, so much is being done to protect the air from pollution. Special stations have been created in different places to monitor the level of air pollution in large cities.

It is important for you and me to take care of plants. They trap dust and fumes with their leaves. Plants perform another important role- They absorb carbon dioxide and produce oxygen. Therefore, in places where there is a lot of vegetation, it is easy to breathe.

Have you noticed that different rooms smell differently? This is true. In a canteen, hairdresser, or pharmacy, particles of odorous substances mix with air particles, and we smell different odors. But remember that clean air does not smell.

Only clean air is transparent and odorless. If you smell gas or burning in the air, contact an adult immediately. They will find out and eliminate the cause or call the Ministry of Emergency Situations.

Double frames are installed in the windows of the houses. This is done so that the layer of air between them does not release heat from the room to the street. Here's another property of air - it conducts heat poorly. How does a person use this property of air in everyday life? In woolen or fur clothing there is a lot of air between the hairs. That is why we feel so warm in it in winter.

Place a mechanical clock on a wooden table and you will hear it tick. Now move them to the far edge of the table until you can no longer hear them. Now put your ear to the table and you will hear the clock ticking again. From this we can conclude that air transmits sound worse than wood.

Read the poem to remember the properties of air that we talked about:

It is transparent, invisible,

Light and colorless gas.

He envelops us with a weightless scarf.

He is in the forest - thick, fragrant,

Like a healing infusion,

Smells of resinous freshness,

Smells of oak and pine.

In summer it is warm,

It blows cold in winter,

When frost colors the glass

And lies on them like a border.

We don't notice him

We don't talk about him

1. Pleshakov A.A. The world around us: textbook. and slave tetr. for 2 grades beginning school - M.: Education, 2006.
2. Bursky O.V., Vakhrushev A.A., Rautian A.S. The world around us. - Balass.
3. Vinogradova N.F. The world around us. - VENTANA-COUNT.

1. Festival of Pedagogical Ideas ().
2. Social network workers ().
3. Public class ().

1. With. 38-41, textbook Pleshakov A.A. The world around us.
2. With. 17 work notebook for the textbook Pleshakov A.A. The world around us.
3. Learn the rhyme from the lesson that helps us remember the properties of air.