Air is present everywhere
Component of Air in Atmosphere
Air supports to life Air is Present Everywhere
Our earth has a thin layer of air called the atmosphere. This air is present everywhere around
us. Air occupies space and weight. It is colourless and odourless.
Activity
Air occupies space
Take a glass and place a crumbled paper at the
bottom of it. Now invert this glass in a tub containing
water. Invert it in a tub having water. Take out the
glass and observe the paper. Does the paper get wet?
No, the paper isn’t wet.
Conclusion: The water does not enter the glass because air is filled in it which does not allow
the water to rush in.
Composition of Air
Air is composed of a mixture of gases.
Nitrogen – 78%
Oxygen – 21%
Carbon dioxide, water vapour & other gases – 1 %
Air also contains smoke from burning of fuels and
exhaust from industries and dust.
Nitrogen – It is the most abundant gas which
occupies nearly four- fifth of the space.
Composition of Air
Oxygen – This gas is utilized by the living organism for respiration. Plants give out oxygen gas
as a product of photosynthesis. Oxygen gas is essential for the purpose of burning.
Carbon dioxide – Green plants use carbon dioxide for photosynthesis and both plants and
animals consume oxygen for respiration and produce carbon dioxide. Air supports to life
Oxygen Availability to Animals and Plants Living in Water and Soil
Plants and animals living in water utilize oxygen in the dissolved form for respiration. This
oxygen content is depleting due to dumping of wastes in water. The whole aquatic habitat is
affected because of water pollution.
Oxygen is required by animals like earthworm living in soil also. These tiny creatures live in
burrows and consume oxygen present in between the soil spaces.
Replacement of Oxygen in Atmosphere
Plants use carbon dioxide for photosynthesis while both plants and animals use oxygen for
respiration. The consumption of oxygen for respiration by plants is very less in comparison to
the oxygen given out by photosynthesis. Plants give out oxygen which is used by animals and
animals give out carbon dioxide that is used by plants.
Uses of Air
Moving air is called as wind. This can be used for various purposes
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Windmill which moves by wind are used for the generation of electricity.
Air helps in the movements of sailing yachts, gliders, parachutes and aeroplanes.
Birds, bats and insects can fly due to the presence of air.
Air also helps in the dispersal of seeds and pollen of flowers of several plants.
Air plays an important role in water cycle.
