What is not related to the properties of air. Topic: “The composition and properties of air. The value of air. Fresh air pollution problem
We repeat those properties of the air-spirit, about which we learned in the previous lessons: the air-spirit is transparent, colorless, has no za-pa-ha, badly conducts heat.
On a hot day, the window glass is cool to the touch, and the under-window and objects standing on it are warm. So pro-is-ho-dit in a way that glass is a transparent body, something passes heat, but it doesn’t heat up -sya. The air is also transparent, so it’s good to let the sun’s rays through.
Rice. 1. Window glass transmits solar rays (Source)
We conduct a simple experiment: we put a glass of steam upside down into a wide vessel filled with water. We will feel a slight resistance and see that water cannot fill a glass of thread, because the air, on- walking in a hundred, does not “give up” its place to the water. If a glass of glass is slightly on a thread, without taking it out of the water, an air bubble will come out of the hundred, and part of the water will enter the glass kan, but even in such a place, a hundred-ka-on, water cannot fill its half-thread with half-a-thread.
Rice. 2. Bubbles of the air-doo-ha you-ho-dyat from the na-klo-nen-no-go hundred-ka-na, giving way to water (Is-toch-nick)
So it pro-is-ho-dit in a way that the air-spirit, like any other body, for-no-ma-is space in the surrounding world.
Using this property of the air-du-ha, man-lo-very learned to work under water without special-ci-al-no-go-stu-ma. For this, a vo-do-laz-ny ko-lo-kol was created: under ko-lo-kol-kol-pak, from-go-tov-len-ny from transparent-no-go ma-te -ri-a-la, hundred-but-vyat-sya people and necessary-ho-di-my both-ru-do-va-nie and co-lo-kol opus-ka-et-sya with help-mo- shchi hoist-eat-no-go crane under the water.
Rice. 3. Vo-do-laz-ny ko-lo-kol (Is-toch-nick)
The air, hovering under the ku-po-lom, allows people to breathe for some time, up to a hundred-precise in order to inspect -tret in the time of waiting for the co-slave, the supports of the bridge or the bottom in-to-storage-ni-li-shcha.
For do-ka-for-tel-stvo-stvo-of the next-du-yu-sche-go-property of the air-du-ha, it is necessary to-ho-di-mo tightly cover with the finger of the left hand from the ve-lo-si-ped-no-go on-so-sa, and with your right hand press the piston.
Rice. 4. Ve-lo-si-ped-ny pump (Is-toch-nick)
Then, do not remove your finger from the hole, from the piston. The finger, which is somehow covered by a hole, feels that the air is pressing very hard on it. But piston with labor, but move-no-xia. This means that air can be compressed. The air is about-la-yes-elastic, because when we let go of the piston, it itself returns to the first -at the beginning of the same.
Elastic-mi-na-zy-va-yut bodies, some-rye, after the termination of compression, they take-ni-ma-yut the first-to-the-initial-form. For example, if you compress the spring-zh-well, and then release it, it will take its original-initial-form.
Compressed air is also elastic, it tends to expand and take its former place.
In order to prove that air has mass, you need to make a self-model scale. Attach the deflated air balloons to the ends of the pa-loch-ki with the help of cattle-cha. Let's put a long pa-loch-ku on se-re-di-well-ko-mouth-koy, so that the ends are equal-no-ve-shi-va-li to each other. Connect them with a thread. We attach cattle-than short-mouth pa-loch-ku to two banks. On-du-eat one ball and again attach it to the pa-loch-ke with the same piece of scot-cha. Let's put it in the same place.
We will see how pa-loch-ka on-clo-nya-et-sya in a hundred-ro-well on-du-that-sha-ri-ka, in a way that air-spirit, on -half-niv-shey ball, de-la-et it is heavier. From this experience, we can conclude that air has mass and can be weighed.
If air has mass, then it must exert pressure on the Earth and everything that is on it. So it is, scientists counted that the air-spirit of the at-mo-sphere of the Earth has an o-o-o-o-o-o-o-o-o-o-o-o-o-o pressure of 15 tons (like three gr-zo-vi-ka), but the man-lo-vek does not feel this, because in the man-lo-ve-che-or-ha-low-me with -keep-lives-to-hundred-accurate number of air-du-ha, someone-ry eye-zy-va-et pressure of the same force. The pressure inside and sleep-ru-zhi urav-but-ve-shi-va-et-sya, that’s why a person doesn’t feel anything.
You-clear-nim, what pro-is-ho-dit with air-spirit-hom during heating and cooling. To do this, we conduct an experiment: we heat a flask with a glass tube inserted into it with the warmth of our hands and we will see that you are out of the tube into the water ho-dyat pu-zyr-ki air-du-ha. This is pro-is-ho-dit in a way that the air in the flask, when heated, is dis-shi-ra-et-sya. If you cover the flask soaked in cold water with a napkin, we will see that water from a hundred-a-on through the tube goes up , because when it cools, the air compresses the air.
Rice. 7. Properties of air-spirit-ha during heating and cooling (Is-point-nick)
To learn more about the properties of air-du-ha, let's do one more experiment: two flasks for-kre-pim on a shta-ti-wa tube. They are equal-but-ve-she-ny.
Rice. 8. Experience in determining the movement of the air-du-ha
But, if one flask is heated, it rises above the other, because hot air is lighter than cold-no-go and under-no-ma -et-sya up. If over a kol-fight with hot air-spirit for-cre-drink in a los-ki with a thin light boo-ma-gi, you will see how they tre-ne-shut and under -no-ma-yut-sya up, ka-zy-vaya move-the-same-tion on-gre-that-th-air-du-ha.
Rice. 9. Warm air under-no-ma-et-sya up
Knowledge of this property of air-du-ha man-lo-vek used-pol-zo-val during the creation of let-ta-tel-no-go ap-pa-ra-ta - air-shower -but-th ball. A large sphere, filled with warm air-spirit, under-no-ma-et-you-so-to the sky and able - live the weight of several people.
We rarely over this we-we-va-e-sya, but we use the properties of the air-doo-ha every day: a coat, a hat or va-rezh-ki do not warm on their own - the air in the fibers of the fabric does not conduct heat well, therefore, the more fluffy the fiber is, the more air is in them ha, which means a warmer thing, made of such a fabric.
Squeeze-ma-e-bridge and elastic-guest air-du-ha use-pol-zu-yut in blowing out of de-li-yah (on-blowing mats, balls) and tires of various mecha-niz-movs (av-to-mo-bi-li, ve-lo-si-pe-dy).
Rice. 13. Ko-le-so av-to-mo-bi-la (Is-toch-nick)
Rice. 14. Ve-lo-si-ped-ko-le-so (Is-toch-nick)
Compressed air-spirit can stop at full speed even iron-lez-but-to-rozh-ny composition. Air-soul-tor-mo-for usta-nov-le-ny in auto-bu-sah, troll-lei-bu-sah, subway co-hundreds. The air-spirit provides-pe-chi-va-et the sound of du-ho-out, percussion, keys-no-du-ho-out in-stru-men-t. When the ba-ra-ban-shchik strikes pa-loch-ka-mi on the tight on-the-well-that skin of the ba-ra-ba-na, she hesitates, and spirit inside-ri ba-ra-ba-na pro-out-of-dit sound. In the pain-ni-tsah, the mouth-new-le-na ap-pa-ra-you ven-ti-la-tion of the lungs: if a man-lo-age can’t self-mo-hundred-I-tel-but breathe, it is connected to such an app-pa-ra-tu, someone, through a special tube, puts it in the lungs some enriched sour-lo-ro-house compressed air. Compressed air is used everywhere: in books-go-pe-cha-ta-nii, construction, re-mon-te, etc.
Rice. 15. Troll-ley-bus (
The air in us and around us, it is an indispensable condition for life on Earth. Knowledge of the properties of air helps a person to successfully apply them in everyday life, household, construction and much more. In this lesson, we will continue to study the properties of air, conduct many exciting experiments, learn about amazing inventions humanity.
Theme: Inanimate nature
Lesson: Properties of air
Let's repeat the properties of air that we learned about in previous lessons: air is transparent, colorless, odorless, and conducts heat poorly.
On a hot day, the window pane is cool to the touch, while the window sill and objects standing on it are warm. This happens because glass is a transparent body that allows heat to pass through, but does not heat up itself. The air is also transparent, so it passes well Sun rays.
Rice. one. Window glass conducts the sun's rays ()
Let's carry out a simple experiment: let's put a glass turned upside down into a wide vessel filled with water. We will feel a slight resistance and see that the water cannot fill the glass, because the air in the glass does not “give way” to the water. If you slightly tilt the glass without removing it from the water, an air bubble will come out of the glass and some of the water will enter the glass, but even in this position of the glass, the water will not be able to fill it completely.
Rice. 2. Air bubbles come out of the tilted glass, giving way to water ()
This happens because air, like any other body, occupies space in the surrounding world.
Using this property of air, a person has learned to work underwater without a special suit. For this, a diving bell was created: under the bell-cap, made of transparent material, people become necessary equipment and the bell is lowered by a crane under the water.
The air under the dome allows people to breathe for a while, long enough to inspect the damage to the ship, bridge piers or the bottom of the reservoir.
For proof next property air, it is necessary to tightly cover the opening of the bicycle pump with the finger of the left hand, and right hand push the piston.
Then, without removing your finger from the hole, release the piston. The finger with which the hole is closed feels that the air is pressing very hard on it. But the piston with difficulty, but will move. This means that air can be compressed. Air has elasticity, because when we release the piston, it itself returns to its original position.
Elastic bodies are bodies that, after cessation of compression, take original shape. For example, if you compress a spring and then release it, it will return to its original shape.
Compressed air is also elastic, it tends to expand and take its former place.
In order to prove that air has mass, you need to make homemade scales. Attach the deflated air balloons to the ends of the stick with tape. We put a long stick in the middle of a short one, so that the ends balance each other. We will connect them with a thread. Attach a short stick to two cans with tape. Inflate one balloon and attach it to the stick again with the same piece of tape. Let's put it back in place.
We'll see the wand lean to the side inflated balloon because the air that fills the balloon makes it heavier. From this experience, we can conclude that air has mass and can be weighed.
If air has mass, then it must exert pressure on the Earth and everything on it. Indeed, scientists have calculated that the air of the Earth’s atmosphere exerts a pressure of 15 tons on a person (like three trucks), but a person does not feel this, because the human body contains a sufficient amount of air that exerts the same pressure. The pressure inside and outside is balanced, so the person does not feel anything.
Find out what happens to air when it is heated and cooled. To do this, let's conduct an experiment: let's heat a flask with a glass tube inserted into it with the heat of our hands and see that air bubbles come out of the tube into the water. This is because the air in the bulb expands when heated. If you cover the flask soaked in cold water napkin, we will see that the water from the glass rises up the tube, because when cooled, the air is compressed.
Rice. 7. Properties of air during heating and cooling ()
To learn more about the properties of air, we will conduct another experiment: we will fix two flasks on a tripod tube. They are balanced.
Rice. 8. Experience in determining the movement of air
But if one flask is heated, it will rise above the other, because hot air is lighter than cold air and rises. If you fix the strips over the flask with hot air thin light paper, you will see how they tremble and rise up, showing the movement of heated air.
Rice. nine. Warm air rises up
Man used knowledge of this property of air when creating aircraft - hot air balloon. A large sphere filled with heated air rises high into the sky and is able to support the weight of several people.
We rarely think about it, but we use the properties of air every day: a coat, hat or mittens do not warm by themselves - the air in the fibers of the fabric does not conduct heat well, therefore, the fluffier the fibers, the more air they contain, which means the warmer the thing, made from this fabric.
Compressibility and elasticity of air are used in inflatable products (inflatable mattresses, balls) and tires of various mechanisms (cars, bicycles).
Rice. 14. Bicycle wheel ()
Compressed air can stop even a train at full speed. Air brakes are installed in buses, trolleybuses, subway trains. Air provides the sound of wind, percussion, keyboard and wind instruments. When the drummer strikes the tightly stretched skin of the drum with his sticks, it vibrates and the air inside the drum produces sound. Hospitals have installed lung ventilation devices: if a person cannot breathe on his own, he is connected to such a device, which delivers oxygen-enriched compressed air through a special tube into the lungs. Compressed air is used everywhere: in printing, construction, repair, etc.
Subject: "The composition and properties of air. The value of air."
Goals: To acquaint students with the composition and basic physical properties of air, to consolidate the idea of gaseous substances.
To teach to be observant. To develop cognitive interest. To cultivate a culture of communication, the ability to work in groups;
Equipment: Flask, glass, test tubes, ball, ball, spirit lamp, potassium permanganate, candle, multimedia projector, presentation "Composition and properties of air"
Lesson type: Communication of new knowledge
During the classes:
I organizational moment (hand out cards - self-assessment)
II. Introduction to the topic
Solve the riddle.
Passes through the nose to the chest
And the way back keeps going
He is invisible and yet
We cannot live without it.
The topic of our lesson
"Composition, properties of air. The value of air for life"
(1slide 2 slides)
What do you know about air?
Fill in 1 column of the card: What do I know?
(3 slide)
What questions do you want answered?
Fill in the 2nd column of the table: What do I want to know?
(slide 4)
III. Work on the topic of the lesson
In the classroom, we see a blackboard, a desk, walls, and outside the house, trees. Can you see air? We do not see the air around us. But in some cases we can detect it. You have all seen small air bubbles on the walls of a glass. If you lower a glass upside down into a glass container with water and slowly tilt it, you will see that water enters its place in the glass.
The entire planet Earth is shrouded in an invisible transparent veil - the atmosphere. Air is everywhere on the street, in the room, in the ground, in the water. Any free spaces on earth filled with air.
Without air, life on earth is impossible. Without air, emptiness and silence would reign forever.
If the earth lost air, like the moon, it would be only a lifeless celestial body. (slide 5)
What is air?
It's not just a gas, but a mixture different gases. How do you understand the word "mixture"? Just 2 centuries ago, scientists learned that air is a mixture of many gases, mainly nitrogen - 18%, oxygen - 21%, CO 2 - 1%. This ratio is necessary for human life, plants and animals. The atmosphere contains water vapor, dust, microorganisms.
It is known that the air shell surrounds not only our planet, it is also on Venus and Mars. However, life does not exist on these planets. Why? (slide 6)
Which of the gases in the air is essential for breathing? Which gas is the most important?
This is oxygen.
Let's try to get this gas.
Experience - 1: Obtaining oxygen by heating potassium permanganate and detecting the gas with a smoldering splinter.
Why did the torch flare brightly? Oxygen supports combustion.
(Slide 11)
Without it, we could not start the car, light the stove, cook on gas stove dinner. Why is oxygen the most important gas? (It is essential for respiration and supports combustion.)
Is the composition of air always the same?
Experience - 2: with a candle:
Why did the candle go out?
Oxygen was used up, and air remained under the jar, in which there is no gas that supports combustion. This means that the composition of the air has changed .. People breathe, animals and everyone exhale carbon dioxide, a fire burns and forms - carbon dioxide. Factories and factories release whole clouds of carbon dioxide into the air.
All living things would have suffocated long ago if not for the plants. They return oxygen to the air. The more greenery, the cleaner the air.
Today you will learn even more about air (its properties).
There are many of them, but today we will learn only a part of the properties.
What properties of air do you know?
Why do I see you? (The air is transparent)
What color notebook?
Blue.
What color is the blackboard in the classroom?
Green.
What color is the air?
Colorless.
Only thick layer air is blue.
Air is compressible, air is elastic. This property is used in cars and railways for braking, used in wheel tires, needed by astronauts, divers, used in a hospital - in intensive care.
Experience - 3: with ball
Experience - 4: A rubber ball bounces off the floor when it hits the floor. Why?
Why do bicycle tires bounce? (The ball is filled with air. It bounces off the floor, because the air compressed when the ball hit the floor tends to expand and take up its original volume.) So the air is elastic.
How is air compressed? (compressor, pump)
Experience - 5: Mystery:
It's so big it takes over the whole world
It is so small that it will fit into any gap. (Air)
Air takes up space. (Lower the test tube into a glass upside down, water cannot enter the test tube - air bubbles come out.)
Air surrounds us everywhere, there is a saying “Air surrounds us everywhere: on the street, in the classroom, in the room. Air cannot be seen, but it can be felt if...
How to feel the air?
Air expands when heated, and contracts when cooled. This means that the volume of air depends on temperature.
Air is a poor conductor of heat.
Many plants wintering under snow do not freeze because there is a lot of air between cold snow particles, and a snowdrift resembles a warm blanket covering the stems and roots of plants.
Air has weight: warm air weighs less, cold air weighs more.
The famous scientist Galileo Galilei weighed air more than 300 years ago. He took a copper ball with a hole and put it on the scales, then pumped air out of the ball, plugged the hole and put it back on the scales. The ball became lighter. So the scientist came to the conclusion that air has weight.
IV . Fixing:
1. What is the atmosphere?
This is the air that surrounds us.
2. What gases does the atmosphere consist of?
Nitrogen, oxygen, carbon dioxide.
3.Values of air for life?
Without air, air communication and heating of buildings could not be carried out. 4. What properties does air have?
Air is transparent, colorless, shapeless, you can see it, you can hear it, you can touch it, it is resilient, it is compressible.
Clean air has great value in life and economic activity people. On average, a person consumes only 1 kg of food and 2 liters of water per day. He needs much more air - about 25 kg. A person can live without food for several weeks, without water - for several days, without air - only a few minutes.
V . Questions. "Why"
List the properties of air and think about what properties of air are we talking about?
Why does the ball bounce off the floor when hit?
Why are windows made with double frames?
Why in very coldy, birds sit ruffled?
What is warmer: in 10 silk blouses or in the 1st woolen one? ( natural material)
We wind on the mustache:
"Street Rules" You need to make sure that the clothes do not sit "in a glove". Otherwise, it will instantly transfer heat from your body to the environment. An air gap must remain between the body and clothing.
V I. Lesson summary
1. What questions were we looking for answers to?
2. What new did you learn in the lesson?
V II.Reflection.
3 columns of the table are filled in - What did you learn?
Compare your answers with the slide and rate yourself.
V III. Homework: §22 - p.64 (1-5) §23p.66 (1-3)
Enbekskaya high school
I approve
Director of Enbek secondary school
Koshakhanova.Sh.Sh.
Lesson topic: Composition and properties of air. Air value
Thing: natural science
Class: 5 B"
Day of the event: February 3, 2015
Teacher: Apekova D.I.
2015
For many billions of years, our Earth, surrounded by a layer of air, has been making its endless run around the Sun.
This layer of air is called the atmosphere. Its thickness reaches 300 km. The atmosphere, like a transparent, invisible veil, envelops our Earth. And what is air, what are its properties and role in life on Earth?
Where is air located and why do we need it
Air fills everything vacancies, and even the smallest cracks.
A transparent glass only seems empty. Try, slowly tilting it, immerse it in water. As the glass fills with water, air will come out of it in large bubbles.
What is the role of air in life on our planet:
- without air life on earth would be impossible. A person can live without food for several weeks, without water for several days, and without air for only a few minutes. Try to stop breathing for a while. After a few seconds, you will feel like you need a deep breath. In the same way, animals also need air.
- And also the air helps us communicate. The sounds made vibrate the air. The generated sound waves cause the eardrum in the ears to vibrate. The vibrations are transmitted to the brain, which perceives them as sound. There is no atmosphere on the moon, so there is absolute silence. And you can communicate only with the help of special devices or gestures.
- Winds and clouds, thunderstorms and polar lights are born in the vast ocean of air. He protects us from meteorites, dangerous ultraviolet and thermal radiation emanating from the Sun. Thanks to this airy “fur coat”, the Earth is not afraid of the cosmic cold either.
- Thanks to the air, planes, helicopters surf the sky, huge airships hang. Flocks of birds fly in the blue sky, huge birds - hunters soar motionlessly. lift force, that keeps them in flight, arises due to the air flow around the curved surfaces of their wings.
- Fish, thanks to the gills, are able to breathe the air contained in the water.
The ocean of air that surrounds our planet held by the forces of gravity. If the Earth lost its air shell, it would turn into a lifeless, devoid of vegetation, desert.
What is air made of
Only two centuries ago, scientists learned that air is mixture of several gases: nitrogen, oxygen and carbon dioxide. Other planets also have an atmosphere:, and the huge giant planets. Mars and Venus are in many ways similar to Earth, but there is no life on them, because the composition of the atmosphere is different.
Oxygen is the most important for breathing. Without it, we cannot get the energy necessary for life from food. During physical work and sports, we breathe deeper and more often to replenish the energy expended for this activity.
There is a simple experience that allows you to get oxygen even at home. Pour ordinary potassium permanganate into a test tube (about 1/4). We fix in vertical position over the fire gas burner or spirits. We withstand 1-2 minutes and bring a smoldering torch to its open end. The torch flares up brightly. The gas released during heating supports combustion and is called oxygen.
And in the next experiment we get carbon dioxide which does not support combustion. two candles different heights set in solution box citric acid(vinegar). We light them up. Then carefully add soda to the solution. There is a rather violent reaction. The candles go out one by one. Small at first, then taller. The lower candle went out first, which means that carbon dioxide is heavier than oxygen and it accumulates below.
From the surface of all reservoirs, soil and vegetation, there is a constant evaporation of water. So in the air always contain water vapor. Humidity depends on their quantity. air masses, the formation of clouds and rain clouds.
What are the properties of air?
The following reasoning will help us answer this question:
- Does air have color? No, the air is transparent. If it had a color, it would color the surrounding plants and objects.
- Why is the sky blue? The fact is that sunlight consists of 7 colors as in a rainbow. As it passes through the atmosphere, the blue color intensifies. We see him.
- If you take 2 rubber balloons and inflate them (to the same size), they will take round shape. This means that the pressure of the blown air was transmitted equally in all directions.
- Now place one of the inflated balloons in the refrigerator and the other in a bucket of warm water. After 10-15 minutes, the chilled ball will decrease in size, and the heated one will increase. Therefore, air expands when heated and contracts when cooled.
- If you have a syringe without a needle at home, pinch its nose with your finger and try to compress the air in the syringe with a piston. The volume of air will noticeably decrease. Release the piston - the volume of air will return to the same. Therefore, air elastic
- In frosty weather, people put on fur coats and warm coats, and birds ruffle their feathers to trap air between the villi and feathers. Because the air poor conductor of heat. Therefore, plants, under a snow blanket, do not freeze even in extreme cold.
All these wonderful properties of air man has learned to use in Everyday life. Recall the elastic tires of cars and bicycles, pumps and many other inventions of mankind. The air makes light yachts and huge sailing ships, rotates the wings of windmills, and makes the ball bounce with his own.
Where is the cleanest and healthiest air
Our breath needs fresh air with sufficient oxygen. But in cities where all the roads are clogged with cars, the air is polluted by their exhaust gases. Add pollution and emissions from factory pipes. Sometimes they form a harmful smog, which hangs over the city like clouds, making it difficult to breathe.
But in forests and parks it is very easy to breathe, because our green helpers absorb harmful carbon dioxide and release oxygen. Algae also produce oxygen, which is why the air on the sea coast is so healing.
But now people are trying to reduce harmful emissions into the atmosphere. Are being created car engines working on electric and even solar energy. Instead of smoking heat pipes, nuclear and solar power plants are being built.
If this message was useful to you, I would be glad to see you