Here we will learn about air and its uses. All living things need air. We know, air is all around us. We cannot see air but we can feel it. We cannot live without it.
When we breathe in, we use the oxygen in the air. When we breathe out, the carbon dioxide made in their bodies goes out into the air. We do this all the time.
One day, Sam and Ron caught two beautiful butterflies. They wanted to show these to their friends at school. The next morning they took their bottles to school.
They observe that Sam's butterfly is not alive since it did not get enough oxygen but Ron's butterfly is alive. From here we learnt that the air around us contains oxygen, carbon dioxide and water vapour. Along with this it also has dust, smoke and germs. It is polluted.
When a street is swept, the dust mixes with the air. Dust and smoke from factories mixes with the air. Smoke from cars, buses and trucks mixes with the air.
To avoid this, cars and buses should not give out smoke. They should be checked every month for this. Factories must be built far away from cities. Even there, they should not pollute the air with smoke.
Sick people cough or sneeze. Germs from their throat and nose mix with the air. We need to cover our face when we cough or sneeze.
After a shower of rain, the dust and the smoke in the air are washed out. Plants give out oxygen while making their food. They also give out water vapour. This keeps the air moist. Growing more trees is one way of keeping the air fresh and clean.
Air and its uses are very important for us to survive but we will be more healthy if we breathe fresh and clean air.
What does air contains?
Air contains tiny dust particles. Air carries dust when it moves. We can see dust in the air when a beam of light falls into a dark room. Air also has a number of very small living things. They cannot be seen and can harm. They are called germs.
Smoke coming out from vehicles, factories makes the air dirty. Dirty air is harmful for us.
Air has water vapour. In the sun water from seas, rivers and lakes, changes into water vapour. Water of wet clothes also changes into water vapour in the sun. Air has many gases.
What are the properties of air?
The properties of air are:
Air fills things: Blow air into a balloon. It becomes bigger as it is filled with air.
Air has weight: A football full of air is heavier than an empty football because of the air present in it.
Air is needed for burning: A candle burns when kept on a table as it gets air. When it is covered with a glass jar, it blows out, as there is no air.
Air is needed for breathing: Air keeps us alive. All plants and animals need air to breathe.
From where do we get fresh air?
We get fresh air from various places and its very good for our health.
Plants make the air fresh and clean. We know air and its uses so, we must grow more plants to get more fresh air.
Play in the open air.
Keep the windows open to let in fresh air.
Do not cover your face while sleeping.
Note: Impure air is bad for our health.