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Air Around Us

Air is present everywhere around us, be it on desk, empty glass or books. Air is contained in each and every empty space. This is the characteristic feature of air. Another property of air is that air is transparent and is colorless. Our planet Earth is surrounded by air, which we call it as the atmosphere. Air is composed of mixed gasses, namely water vapor, oxygen, carbon dioxide, nitrogen and dust and smoke (Figure 6.1).

Figure 6.1 Composition of air


Water Vapor:

Water vapor formed by transpiration and evaporation process is an important component of air composition, as it maintains the water cycle on the Earth. Water vapor present in the air is further condensed in the form of rain, hail, and snow.



Oxygen present in the air is essential for life to exist as we inhale oxygen and exhale carbon dioxide. The only source of oxygen in earth plants. Plants produce oxygen while their preparation of food, ie., photosynthesis. We can easily test the presence of oxygen in the air. We need a candle and an empty glass container. Light the candles and invert the glass container on it. If the glass container and candle are of the same size, then we cannot see the candle burning. But if the glass is of larger size, then we can see the candle. This difference is due to the presence of air in the empty glass. The air enables the burning of the candle, or more specifically, the oxygen present in the candle is required for the burning of the candle.



Nitrogen constitutes a major part, nearly four-fifth part of the air. Nitrogen present in the air is used for various purposes in our ecosystem, such as nitrogen fixation of soil. Nitrogen present in the air does not support burning of fire, unlike oxygen.

Carbon dioxide:

It is a very well known fact that we exhale carbon dioxide during the respiration process. And carbon dioxide in the air is used up by the plants for photosynthesis process. Thus, carbon dioxide along with other inert gasses forms a small part of the air around us.


Dust and smoke:

Dust and smoke caused by pollution, cooking and other industrial processes also form a component of the air. It is better to release such dust particles and smoke high in the air, as some of the gasses are hazardous to the health of plants and animals.


The composition of Air:

Nitrogen – 78.08%

Oxygen – 20.95%

Water vapor, carbon dioxide, and other gasses ~ 1%


The significance of Air:

Air can be used by windmills to generate electricity

Air helps in the fertilization process of plants by moving across the pollens.