Air is Around Us

The space around us is filled with air. However we cannot see air,we cannot smell it and we cannot taste it. How do we know that air is around us.? We can feel air. We can feel when it moves because it pushes against us. We can also feel when we move in it. What do you feel when you put your head out of the bus while the bus is moving? Can you feel it?

Things you can do

• Swing your arms round quickly. What do you feel?
• Take a piece of paper in your hand and swing clockwise.What can you feel?
• Take a piece of cardboard and fan towards yourself. Do you feel something at your face?
• Open a umbrella and hold it in front of you. Run as fast as you can with the umbrella. Can you feel something that is pushing against you?

Moving Air

Moving air is called wind. It can push against things and make them move. A wind can be gentle or strong. Avery gentle wind is called breeze. A strong wind is called gale. Have your heard about the the typhoons, hurricane, tornado and storm. These are very strong wind that can blow down trees, buildings and even yourself if you are not extra careful.They can cause a lot of damages if they occurs.

The wind can also do many useful things too. It works the windmills, moves a sailing boat, give us fresh air and for us to breath daily. It also help to scatters the plants pollen, seeds and even fruits for the next generations to grow and survive.

The Atmosphere

We have known that the air is all around us. Actually our earth is completely surrounded by layers of air called the atmosphere. We can say that the earth is bathed in an ocean of air with us living at the bottom of it. The atmosphere is very important to all life on the earth. Do you know why?

Without the atmosphere, we would not be able to live on the earth. There would be no air for us to breathe. The earth would be very, very hot in the day and would be very very cold at night. Dangerous rays from the sun would reach earth and kills all living life. I believe that no one would like to live without air around us.

The atmosphere is about 900km thick. It can be divided into different part of layers. The lowest part of the atmosphere where we live is called troposphere. It is about 8km to 17km thick. This is where the weather changes takes place. The wind blows and clouds form up here. The thunder and lightning also takes place here too. The air is also dense in these layers.

Above this layers of stratosphere. |It goes up to a height of about 80km above sea level. There are no clouds or storm in the region. Therefore the airlines prefers to fly their planes in this region. As we go higher, the air in the atmosphere gradually thins out. That is the air become less dense where all the scientist call these space begins just beyond the earth`s atmosphere.

What is air made of ?

Air is a mixture of gases. A sample of a dry air around us contains 78% Nitrogen, 21% Oxygen, 0.03% carbon dioxide and 1% rare gases by volume. Rare gases consist of argon, neon, helium, krypton and also xenon. Air is also water vapour. The amount of water vapour varies, and is about 3% in tropical countries where the air is most. Besides gases and water vapour,we can also find dust, pollen, spores, and germs in the air. Over cities, the air usually contains soot and harmful gases.

However, the air is much cleaner in the stratosphere area. There is a type of oxygen in this layer called ozone. Ozone is poisonous, but it is important because it absorbs ultravoilet radiation from the sun and prevents most of it from reaching the earth. Otherwise the ultaviolet rays would kill most living things and burn us severely.