Properties and Composition of Air

We all know that air exists everywhere in our environment.

You can’t see it, you can’t taste it, and if you try to reach out and touch it, people might think you’re a little nuts.

This invisible substance called air is really a mixture of several gases.

Although we cannot see air, we can only feel it. Air can be felt by seeing moving objects around us.

The wind is air in motion. Wind forms when the Sun heats one part of the atmosphere differently than another part.

Let’s study the properties of air.

Air takes up space. If it did not take up space, the balloon would not be blown up.

When you use a pump to blow up a football, you are putting air into it - this air takes up space which is why the football expands.

Air has weight. If it didn’t, the blown balloons and empty balloons would stay level.

Air is made up of a mixture of gases and, gases can be compressed.

This air which is compressed can be used in spray cans to clean things that are sensitive, such as keyboards.

Air pressure decreases with increasing altitude.

At the top of Mount Everest, with air pressure so low, many people have trouble breathing and thinking.

You’ve probably also noticed that your ears pop during the take-off or landing of a flight.

This is caused by the difference in air pressure on either side of your eardrums.

Air in our atmosphere is made up of a mixture of colourless gases.

The air around us consists of gases namely Nitrogen, Oxygen, Carbon-dioxide water vapour and many other gases in trace amount.

Oxygen is an important component of air and is essential for the survival of life on earth.

Oxygen makes up almost 21% of the total gases in air.

This component of air is responsible for respiration and many more activities in our body.

You will notice that wood or anything combustible burns brighter in the presence of pure oxygen than in air.

The rust that we see on an exposed iron is caused due to oxidation, a process that occurs when iron comes in contact with it in the air.

There would be no animal life or green plants without carbon dioxide.

Carbon dioxide is a waste product of human respiration. It occupies about 0.04% of the earth’s total atmosphere.

Every time something organic is burnt, it makes carbon dioxide.

Plants use carbon dioxide to make food by the process of Photosynthesis

Trees are potent organisms for absorbing and removing emissions from the air. Cutting them down stops that process.

Let’s move on to another major component of air, that is Nitrogen.

Nitrogen is found in stars, plants, animals, and even our own DNA.

Although we usually think of the air we breathe as only oxygen, it is actually 78% nitrogen.

Nitrogen is also used by nature, and the nitrogen cycle describes nitrogen’s movement between plants, animals, bacteria, the air, and even the dirt.

Water is constantly cycling through the atmosphere.

We see clouds nearly every day. Have you ever wondered what they are made of?

Clouds are made up of tiny droplets or frozen crystals of water

This indicates that there is a component of air which is responsible for this

This component of air is called water vapour.

Apart from the natural gases, air also contains things like smoke and dust.

Smoke and dust particles occupy less than 1% of the earth’s atmosphere.

Dust particles are also present in our atmosphere which we observe when we see a ray of light in a dark room.


The world we live in is covered with air, called the atmosphere.

When air moves with speed, it is called wind.

Air is a mixture of gases, water vapour, and other substances, and it has specific properties or characteristics.

The composition of air consists of Nitrogen, Oxygen, Carbon dioxide, water vapour and many other gases in trace amount.

The End