Schematic drawing of air during cooling. Air expands when heated and contracts when cooled
Friction with the air, of course, occurs, and at the same time a certain amount of heat is released, but another physical process called aerodynamic heating heats up the skin of the descent vehicle and causes fireballs flying towards the ground to burn and explode.
As is known, a shock wave is formed in front of a body moving in a gas at supersonic speed - a thin transition region in which a sharp, abrupt increase in the density, pressure and speed of the substance occurs. Naturally, as the gas pressure increases, it heats up - a sharp increase in pressure leads to a rapid increase in temperature. The second factor - this is actually aerodynamic heating - is the braking of gas molecules in a thin layer adjacent directly to the surface of a moving object - the energy of the chaotic movement of molecules increases, and the temperature rises again. And the hot gas heats up the supersonic body itself, and the heat is transferred both by thermal conductivity and by radiation. True, the radiation of gas molecules begins to play a noticeable role at very high speeds, for example, at the 2nd cosmic speed.
The problem of aerodynamic heating has to be faced not only by spacecraft designers, but also by developers of supersonic aircraft - those that never leave the atmosphere.
It is known that the designers of the world's first supersonic passenger aircraft - Concorde and Tu-144 - were forced to abandon the idea of making their aircraft fly at a speed of Mach 3 (they had to be content with “modest” 2.3). The reason is aerodynamic heating. At such a speed, it would heat up the skins of the airliners to such temperatures that could already affect the strength of aluminum structures. Replacing aluminum with titanium or special steel (as in military projects) was impossible for economic reasons. By the way, you can read about how the designers of the famous Soviet high-altitude interceptor MiG-25 solved the problem of aerodynamic heating in
LESSON SUMMARY ON THE ENVIRONMENT
FOR 3rd CLASS.
Educational and educational complex "School of Russia"
Subject: Air and its protection.
Objective of the lesson:
To introduce students to the composition and properties of air.
Tasks:
- educational:
to develop knowledge about the importance of air for all living things
Earth;
in the process of experiments and practical work to form knowledge
about the basic properties of air;
develop practical skills to work with laboratory materials
equipment, conduct experiments, conduct observations;
analyze, summarize and draw conclusions based on the results of observation
Denium;
learn to work with a hypothesis (assumption throughactive method
and practical approach).
Educational:
create conditions for the student’s personal development; revitalization
independent activity and group work; development method-
ability to constructive creativity, observation, ability to compare
draw conclusions;
- educational:
create conditions for fostering respect for the environment
environment;
create conditions for developing a communicative culture, skills
work in groups, listen to and respect the opinions of others;
feelings of mutual assistance and support.
Equipment: for students: textbook “The world around us, grade 3” by A.A. Ple-
Shakova; workbook; magnifying glass, wood leaf
from the teacher: textbook, workbook, presentation, electronic supplement
textbook; plastic bag, laboratory equipment: flask, alcohol lamp,
cloth for experiment, magnifying glass, leaf of wood, computer, presentation, multimedia
new projector, screen.
PROGRESS OF THE LESSON.
I. Organizational moment (2 min)
Checking seating and readiness for class.
Today in class you will work in groups. What rules of working in a group must be remembered and followed?
(Work to the best of your ability; listen to everyone
each group member attentively, without interrupting;
speak clearly and to the point; support your comrades;
if you don't agree with someone, say it politely,
choose as captain the one who can choose
the best solution together with everyone; remember: perform
It’s an honor to die on behalf of the group)
II. Updating knowledge. Checking homework. (4 min)
Target: consolidation of knowledge acquired in previous lessons
( Presentation ):
Summary of the stage.
III. Self-determination for activity. (1 min)
Guess the riddle:
Passes through the nose into the chest
And the return is on its way.
He's invisible, but still
We cannot live without him.
(Air)
How did you guess?
(We breathe air, we cannot live without it,
but we don’t see it)
What do you think will be discussed in class today?
(About air, its composition and properties)
IV. Work on the topic of the lesson (20 min)
Conversation
There are 5 oceans on our planet. What are they called?
(Arctic, Pacific, Atlantic, Indian and Southern)- There is another very important ocean in the world - the largest, and every day, every hour, every minute, without noticing it, we “swim” in it. What is the name of this ocean? (Air)
The ocean of air has its own scientific name. Our students will tell you more about this...
Student performance . Pre-prepared students make a presentation.
Target: working with educational, popular science texts that are accessible to primary schoolchildren, correct and conscious reading aloud. Construction of a monologue statement on a proposed topic, on a given question .
The layer of air surrounding our planet is called the atmosphere.
The atmosphere is a gigantic shell of air that extends upward for hundreds of kilometers. The thickness of the atmosphere varies in different parts of the planet.
The atmosphere protects the earth from excess heat and cold, from excessive solar radiation. If it suddenly disappeared, then water and other liquids on Earth would instantly boil, and the rays of the sun would burn all living things.
The ocean of air - the atmosphere - is very important for life.
Can living things survive without air? (No)
Why? (You could suffocate and die)
Indeed, if you take a deep breath, cover your mouth and nose with your palm and count to yourself: one, two, three... Before you can count to 60, you will really want to take a breath of fresh air.
When a person goes underwater, climbs high into the mountains or flies into space, he should always have a supply of air with him.
If the ocean of air suddenly disappeared, then our planet would become a lifeless planet in a few minutes.
Why is the air ocean so important? (Children's answers)
The air shell of the Earth is its amazing “shirt”. Thanks to it, the planet does not overheat from the sun's rays and does not freeze from the cosmic cold. This “shirt” protects the Earth from meteorite impacts. They simply burn in the air. So the Earth simply needs an air “jacket,” and only thanks to it does intelligent life exist on Earth, the only planet in the Solar System.
Is it possible to verify that air exists? What do you think?
(Children's answers)
It is very easy to verify that air really exists. Try waving your hand. How do you feel?
(Air movement)
I have an empty plastic bag in my hands. I'll wave it and pinch the ends. Why did the bag inflate and become elastic?
(There's air there)
What is the significance of air for humans, plants and animals?
(Air is necessary for breathing, protects the Earth from
overheating and cooling, from meteorites, from
harmful rays of the sun).
Well done!
Physical education minute (1 min)
We'll rest a little
Let's stand up and take a deep breath.
Hands to the sides, forward.
The bunny is waiting at the edge of the forest.
The bunny was jumping under the bush,
Inviting us into your home.
Hands down, on the waist, up,
We are running away from everyone.
(Running in place.)
Let's quickly run to class,
We'll listen to the story there.
Checking the fit.
Practical work “composition and properties of air”. Work in a notebook (pp. 27-29)
Target: teach children to observe, hypothesize, analyze and draw conclusions based on practical actions.
Read the poem. What can you learn about air from it?
(Air is a mixture of gases)
Open the textbook on page 46. Consider the “Composition of Air” diagram.
What gases are included in air?
(Oxygen, nitrogen and carbon dioxide)
What is the most gas in the air? (Nitrogen)
What gas is the least in the air? (Carbon dioxide).
People learned what composition air has only 200 years ago. Joseph Priestley and Antoine Lavoisier were the first to study the composition of air and its properties.
When living things breathe, they absorb oxygen from the air and release carbon dioxide.
Working in pairs
Cover your textbooks.
Open your notebooks on page 27 and complete task No. 1 yourself.
(On your own or with the help of a textbook, sign up for
diagram, which gaseous substances are included in the air
spirit. Mark with pencils of different colors (according to your preference)
boron), what gas living beings absorb when breathing,
and which one is highlighted. Decipher the devices you used
catchy designations).
Exchange notebooks and check each other's work. Draw a conclusion, evaluate the work.
Return the notebooks to each other. Test yourself using the textbook. Correct the errors. Evaluate your work. Select the desired icon:
Bottom line . – Who completed the task without errors?
Well done.
Who experienced difficulties during the task?
Correct your mistakes and pay more attention in class.
Guys, what properties does air have?
(The air is elastic, ... (children’s assumptions)
Let's do some experiments and see if you're right.
During practical work we will complete task No. 2 in the notebook.
Look at the table and tell me what questions we should answer as a result of our observations?
(Fill out the table based on the research results.
Properties of air
What we study
Conclusion
Is the air transparent or opaque?
Does air have color?
Does the air have a smell?
What happens to air when heated?
What happens to air when it cools?
- How do you think the first question should be answered? (children's answers)
What will help us prove this? (children's hypotheses).
- Guys, take the textbook, tell me, is it transparent?
Look at the door, is it transparent? Are others visible through these objects?
Why do we see a door, a textbook, a blackboard, a desk? Discuss and give your guesses.
( The air is transparent)
- Record the output in a table. (The air is clear)
What's the next question? (Does air have color?)
How can you answer this question? How to prove this?
(Children's statements)
(If the children find it difficult, the teacher prompts them)
- What color is the board? (Green)
What color is the cabinet? (Brown)
What color is chalk? (White)
What color is the air? (Has no color )
Record your findings in a table. (Air has no color).
Read the third question.
(Does the air have a smell?)
What can you guess? What evidence can we use?
(Children's statements)
(If the children find it difficult, the teacher prompts them)
Guys, raise your hand, which one of you wasin a hair salon, in a cafeteria, in a clinic? Imagine being asked to find out where you are with your eyes closed? Is this possible? How? Discuss and give your guesses.
( We can determine where we might be by smell. We know that odorant particles mix with air particles. Thanks to this, we smell. But clean air has no smell.)
Record the output in a table. (The air has no smell)
- WhatWhat happens to air when it is heated and cooled? We will find out this through experiments.
Experience No. 1.
Target: find out what happens to air when heated.
Let's take a flask with a tube. Let's put the tube in the water. What are we seeing?
(Water does not enter the tube; air does not let it in).
We will heat the flask. What happens now?
(Air bubbles began to come out of the tube.)
( Air expands when heated ) - entry in a notebook).
Experience No. 2.
Target: find out what happens to air when it cools.
Place a cold, damp cloth on the flask. What are we seeing?
(The water rises in the tube. The air seems to give way
water part of its place)
What conclusion can be drawn based on the observations?
( When cooling, air compresses) - notebook entry)
Air has another interesting property. In order to find out, let’s complete task No. 4 on p. 28 in the workbook.
Read the story of the Wise Turtle and complete her tasks.
(One of the students reads the story aloud)
Think about what property of air is described in the story?
(Children's guesses)
Let's check ourselves. Read the text in the “Test yourself” section.
Well done!
So, what properties does air have?
(The air is transparent, colorless, odorless, when
When heated it expands and when cooled it contracts.
elastic, conducts heat poorly)
Well done!
V. Physical education minute (1 min)
To become strong and agile
Let's start training.
Inhale through your nose and exhale through your mouth.
Let's breathe deeply, and then
Step in place, slowly,
How nice the weather is!
We checked your posture
And they pulled their shoulder blades together.
We walk on our toes
And now - on the heels.
Checking the fit.
VI. Consolidation of the studied material. Work in a notebook (5 min)
Target: consolidate acquired knowledge
Read task No. 3 on page 28 in your notebook.
(Use a schematic diagram to show how the
relies on air particles for heating and cooling)
What properties of air must be taken into account in order to complete the task correctly?
(When heated, air expands, and when cooled,
Denia is shrinking)
How to explain that air expands when heated? What happens to the particles that make it up?
(The particles begin to move faster, and between
ki between them increases)
In the first rectangle, draw how air particles are arranged when heated.
How to explain that air compresses when cooled? What happens to the particles that make it up?
(The particles begin to move more slowly, between
the horrors between them are decreasing)
Draw in the second rectangle how air particles are arranged as they cool.
(After completing the task, a self-test is carried out on the slide:
VII. Reflection (4 min)
Group work
Read the second task on p.48. Complete it.
(Read the text “The air must be clean.” Find information in it: About the sources of air pollution; about ways to protect air purity.)
What pollutes the air?
(Plants and factories, cars)
What methods of air protection do you know?
(Installation for collecting soot, dust,
toxic gases, electric vehicles)
Conversation (5 min)
There is a factory in the city. Clouds of smoke poured out of its chimney day and night. Residents of the city coughed, sneezed, and some were even admitted to the hospital. They even wanted to close the factory, but how could they manage without goods?
One day, smoke stopped pouring out of the factory chimney. It soon became clear that smoke eliminators had been attached to the pipe, which prevented soot particles from flying out of the pipe.
And here's what's interesting. The soot is now carefully collected and sent to a plastics factory, where various plastic things are made.
In a word, everyone benefits from the smoke trap - both city residents, the factory (it sells soot), and plastic manufacturers.
Name ways to protect air purity.
(Air purification units, electric vehicles)
Can you somehow influence the cleanliness of the air?
(You can plant plants, they purify the air)
Why do plants absorb carbon dioxide and release oxygen?
(Children's guesses)
Let's take a close look at the leaf of the tree. The lower surface of the sheet is covered with a transparent film and dotted with small holes. They are called "stomata". They open and close, collecting carbon dioxide. In the light of the sun, sugar, starch and oxygen are formed from water that rises from the roots along the stems of plants and carbon dioxide in green leaves. That’s why plants are called “the lungs of the planet.”
VIII. Summing up the lesson. (2 min)
What is air? (Mixture of gases - nitrogen, oxygen and carbon dioxide)
Name the properties of air.
(The air is transparent, colorless, odorless, elastic,
expands when heated, contracts when cooled,
conducts heat poorly)
What new did you learn in the lesson?
IX. Homework (1 min)
Workbook: No. 5 (p. 29)
Young children often ask their parents about what air is and what it usually consists of. But not every adult can answer correctly. Of course, everyone studied the structure of air in natural history classes at school, but over the years this knowledge could be forgotten. Let's try to make up for them.
What is Air?
Air is a unique “substance”. You can't see it, touch it, it's tasteless. This is why it is so difficult to give a clear definition of what it is. Usually they just say - air is what we breathe. It is around us, although we do not notice it at all. You can only feel it when a strong wind blows or an unpleasant odor appears.
What happens if the air disappears? Without it, not a single living organism can live or work, which means that all people and animals will die. It is indispensable for the breathing process. It is important how clean and healthy the air that everyone breathes is.
Where can I find fresh air?
The most beneficial air is found:
- In forests, especially pine ones.
- In the mountains.
- Near the sea.
The air in these places has a pleasant aroma and has beneficial properties for the body. This explains why children's health camps and various sanatoriums are located near forests, in the mountains or on the sea coast.
You can enjoy fresh air only away from the city. For this reason, many people buy summer cottages outside the locality. Some move to a temporary or permanent residence in the village and build houses there. Families with small children do this especially often. People are leaving because the air in the city is highly polluted.
Fresh air pollution problem
In the modern world, the problem of environmental pollution is especially pressing. The work of modern factories, enterprises, nuclear power plants, and automobiles has a negative impact on nature. They emit harmful substances into the atmosphere that pollute the atmosphere. Therefore, very often people in urban areas experience a lack of fresh air, which is very dangerous.
Heavy air inside a poorly ventilated room is a serious problem, especially if it contains computers and other equipment. Being in such a place, a person may begin to suffocate from lack of air, develop pain in the head, and become weak.
According to statistics compiled by the World Health Organization, about 7 million human deaths per year are associated with the absorption of polluted air outdoors and indoors.
Harmful air is considered one of the main causes of such a terrible disease as cancer. This is what organizations involved in the study of cancer say.
Therefore, it is necessary to take preventive measures.
How to get fresh air?
A person will be healthy if he can breathe fresh air every day. If it is not possible to move out of town due to an important job, lack of money, or for other reasons, then you need to look for a way out of the situation on the spot. In order for the body to receive the necessary amount of fresh air, the following rules should be followed:
- Be outside more often, for example, take evening walks in parks and gardens.
- Go for a walk in the forest on weekends.
- Constantly ventilate living and working areas.
- Plant more green plants, especially in offices where there are computers.
- It is advisable to visit resorts located by the sea or in the mountains once a year.
What gases does air consist of?
Every day, every second, people inhale and exhale without thinking about the air at all. People do not react to him in any way, despite the fact that he surrounds them everywhere. Despite its weightlessness and invisibility to the human eye, air has a rather complex structure. It involves the interrelation of several gases:
- Nitrogen.
- Oxygen.
- Argon.
- Carbon dioxide.
- Neon.
- Methane.
- Helium.
- Krypton.
- Hydrogen.
- Xenon.
The main share of air is occupied nitrogen , the mass fraction of which is 78 percent. 21 percent of the total is oxygen - the most essential gas for human life. The remaining percentage is occupied by other gases and water vapor, from which clouds are formed.
The question may arise, why is there so little oxygen, just a little more than 20%? This gas is reactive. Therefore, with an increase in its share in the atmosphere, the likelihood of fires in the world will increase significantly.
What is the air we breathe made of?
The two main gases that make up the air we breathe every day are:
- Oxygen.
- Carbon dioxide.
We inhale oxygen, exhale carbon dioxide. Every schoolchild knows this information. But where does oxygen come from? The main source of oxygen production is green plants. They are also consumers of carbon dioxide.
The world is interesting. In all life processes, the rule of maintaining balance is observed. If something went from somewhere, then something came from somewhere. Same with air. Green spaces produce the oxygen that humanity needs to breathe. Humans consume oxygen and release carbon dioxide, which in turn feeds plants. Thanks to this system of interaction, life exists on planet Earth.
Knowing what the air we breathe consists of and how much it is polluted in modern times, it is necessary to protect the plant world of the planet and do everything possible to increase the number of green plants.
Video about air composition
Introduction
Purpose of the study:
learn about the importance of clean air for human life on earth.
Research objectives:
consider questions about the importance of air for representatives of wildlife, natural and human-caused sources of air pollution, and the most important measures for its protection;
develop the ability to analyze, generalize, and draw conclusions.
Relevance of the topic:
Environmental pollution by industrial enterprises and vehicles harms public health and is the most acute environmental problem of great social and economic importance.
Hello! I am Polina Proskurina, I am Nastya Baklanova. Once, during a lesson on the surrounding world at school, we covered the topic “About Air”. We became interested in this topic and decided to learn more about the importance of clean air for the life of living creatures on earth.
Therefore, we chose the theme of our project without hesitation - “About air.” The goal of our project is to study the composition of air and study its properties. We came up with 2 hypotheses:
1) air pollution occurs naturally;
We found information about air in encyclopedias, reference books, on the Internet, from educational programs on television, and conducted experiments.
Air - this is the lower layer of the atmosphere. We live at the bottom of the ocean of air. It extends above us for several hundred kilometers. This ocean has no shores; it surrounds the entire globe.To live a long and active life, we need fresh air. People who spend little time outdoors expose themselves to serious complications. Breath is invisible food, without which we cannot live for 5-7 minutes. It is known that a person can live up to 30 days without food, and only a few minutes without air. If possible, you should sleep with the windows open to create good ventilation. You need to run, swim, dance, walk in the fresh air, while breathing slowly and deeply.
We decided to conduct several experiments to find out what properties air has.
1. Is the air transparent or opaque?
We see surrounding bodies through it. Let’s compare: a door or a book are opaque, other objects cannot be seen through them. This means the air is transparent.
2. Does air have color?
The cabinet is yellow, the chalkboard is brown, the indoor plants are green. But the air has neither these colors nor any other color. This means the air is colorless.
3. Does the air have a smell?
We noticed that different rooms smelled differently.
In a canteen, hairdresser, or pharmacy, some odorous substances mix with air particles, and we smell different odors. But clean air has no smell.
4. What happens to air when it is heated and cooled?
We will find out this through experiments.
Experience 1.
Purpose of the experiment: to find out what happens to air when heated.
We took a flask with a tube. They lowered the tube into the water. We noticed that water does not enter the tube - the air “does not let it in.” They began to heat the flask. Air bubbles were coming out of the tube.
We concluded that when air is heated, it expands.
Experience 2.
Purpose of the experiment: to find out what happens to air when cooled.
We placed a cold, damp cloth on the flask and saw how the water began to rise in the tube. The air seems to give up some of its space to the water.
We concluded: when cooled, air compresses.
So, air is transparent, colorless, odorless, expands when heated, and contracts when cooled.
We learned that airis a mixture of gases:nitrogen, oxygen and carbon dioxide. When living things breathe, they absorb oxygen from the air and release carbon dioxide.
Humans and other living beings need clean air to breathe. But in many places, especially in big cities, it is polluted.
As long as humans did not interfere with natural processes, they occurred in such a way that the balance of atmospheric elements was maintained by itself.But gradually technology developed so much that human activity began to seriously influence the natural course of events. All this leads to a disruption of the natural balance. In December 1952, urban smoke mixed with fog killed 4,000 people in London. This was a very serious warning to residents of cities all over the planet. The English government urgently passed a law banning the use of fuels that leave smoke in cities. And yet, the problem of urban smoke has not yet been solved.Some factories and factories emit toxic gases, soot, and dust from their chimneys. Cars emit exhaust gases that contain many harmful substances. Air pollution threatens human health and all life on Earth!
Nowadays, a lot is being done to protect air purity. Many enterprises operate installations that capture dust, soot, and toxic gases. Scientists have developed new cars - electric cars that will not pollute the air. Special stations have been created in different places; they constantly monitor the cleanliness of the air in large cities.
On the territory of our Belgorod region air pollution occurs from motor vehicles, enterprises of the mining and metallurgical industry, and production of building materials.
To reduce emissions vehicles into the environment in most organizations andenterprises in the region organized timely repairs, adjustments andmaintenance of systems and units, developed and implementedmeasures to reduce the volume of cargo transportation and reduce fuel consumption, some vehicles are being transferred to gas fuel.
During the study, we learned about the composition of air, its properties, how you can observe the air, and what benefits fresh air brings. The study confirmed the second hypothesis:
2) air pollution is caused by human activities.
We enjoyed exploring air because we learned a lot about it.
He is transparent and invisible,
Light and colorless gas.
With a weightless scarf
It envelops us.
He is in the forest - thick, fragrant,
Smells of resinous freshness,
Smells of oak and pine.
In summer it is warm,
It blows cold in winter,
When frost paints the glass
And lies on them like a border,
We don't talk about him.
We just breathe it in -
We need him!
Thank you for your attention!
Internet resources used:
1. http://*****/article_24
2. http://rudocs. /docs/index-320968.html
3. http://mamatanya. *****/laborator/air. html#1
http://ru. wikipediaUsed literature:
1. On your own or with the help of a textbook, label on the diagram what gaseous substances are included in the air.
Mark with pencils of different colors (of your choice) which gas living beings absorb and which they emit when breathing.
Decipher the symbols you used:
2. Based on the research results, fill out the table.
3. Use a diagram to show how air particles are arranged when heated and cooled. (Denote air particles with circles.) 
Wise Turtle and complete her tasks.
Air is the protector of living things
Herbaceous plants overwintering under snow do not freeze because there is a lot of air in it. Thanks to the air, cold snow serves as a warm “blanket” for plants.
By winter, animals' fur becomes thicker, and birds' feathers become thicker. More air is retained between thick hairs and feathers, and the animal is warmer in winter.
1) These facts are explained by another property of air, which we have not yet talked about. Think about what this property is - air does not conduct heat well.
2) Give an example proving that this property of air is important not only for plants and animals, but also for humans - there is air between the body and a person’s clothes and in the clothes themselves, so clothes retain the heat of our body
Test yourself.
5. Come up with and draw a poster “Take care of the air!” on a separate sheet of paper.
Look what your friends have drawn. If you have ideas on how you can help protect the air, discuss them and do it.
6. According to the instructions in the textbook, find out and write down what is being done in your city to protect the air.
In our city, to protect the air, enterprises install filters on pipes, and trees are planted in parks and forests. New transport interchanges are also being built in the city to eliminate traffic jams.
