Air Around Us Class 6 notes - Chapter 15

According to the CBSE Syllabus 2023-24, this chapter has been renumbered as Chapter 11.

What is the Composition of Air?

Air is present all around us. We can feel the presence of air but cannot see the air around us. Air is a mixture of gases. The different components of air include – 78% nitrogen, 21% oxygen, 0.9% argon, 0.04% carbon dioxide, and about 1% water vapour. Air plays an important role in breathing and burning. The existence of life on the planet Earth is mainly because of the presence of air.

For more information on the Composition of Air, watch the below video

To know more about the Composition of Air, visit here.

How is the oxygen replaced in the atmosphere?

As we all know, air contains only 21% oxygen. All living organisms, including plants, require oxygen for breathing. Plants play an important role in the balance of oxygen and carbon dioxide in the atmosphere and are maintained through the process of photosynthesis.

Photosynthesis is a biological process in which all green plants synthesize their food in the presence of sunlight, water, and carbon dioxide. Oxygen gas is the most important by-product of this process.

To know more about Oxygen Cycle, visit here.


The vast white fluffy clouds seen in the blue sky are actually millions of tiny water droplets held up by air. The water vapour that evaporates from seas, rivers and other water bodies travel up into the sky to form clouds.

To know more about Cloud Formation, visit here.

Air is Everywhere

  • Our earth is surrounded by a thin layer of air.
  • We cannot see air, but we can feel its presence in many ways.
  • Leaves of the trees rustle, and the branches sway in the wind.
  • The clothes were hanging on a clothesline swing because of the presence of air.
  • This layer extends up to many kilometres above the surface of the earth and is called the atmosphere.

Colour of Air

Air has no colour, and one can see through it. It is transparent.

Moving Air

Moving air can be termed as the wind. We can feel the wind as it sways leaves on a tree or during storms the wind blows at a very high speed, even uprooting trees in their way.

Moving Air - Wind


The layer of air that covers the Earth extends up to some kilometres in space, this is the atmosphere.

Air as a Mixture

Air is a mixture of different gases and particles; oxygen, water vapour, nitrogen, carbon dioxide, dust and smoke.

Main components of Air

The main constituents of air are nitrogen and oxygen. Air is 78 per cent nitrogen, just under 21 per cent oxygen, and the rest is water vapour, carbon dioxide and small concentrations of other gases.

To know more about the Components of Air, visit here.

Water vapour

Water vapour is present in the air as a gaseous form of water and is responsible for humidity.

Dust and smoke

The minor particles that are present in the air. The high amount of these particles in the air can cause pollution.

Breathing in Humans

Both animals and humans breathe by inhaling oxygen and exhaling carbon dioxide. This process is termed respiration.

Breathing in humans

Breathing in Plants

Plants respire through the process of photosynthesis. In this process, they take in carbon dioxide and give out oxygen as a waste, which we breathe in.


Photosynthesis is a biological process used by plants to prepare their food with the help of sunlight and energy. Carbon dioxide is taken in, and oxygen is given out as a waste product in this process.


Breathing in Fish

Oxygen dissolved in water is used by fish to breathe.

Symbiotic Cycle

  • Organisms usually come together where each benefit from the other.
  • We get oxygen and other products from plants, and they get not only carbon dioxide but other advantages from us.
  • This is in the form of a cycle. Respiration and photosynthesis lead to the recycling of oxygen and carbon dioxide in the environment.


Fire requires oxygen for sustenance.

Burning Fire


Learn more about the Water from the topics given below:

Uses of Air Movement of Air
Components of Air Importance Of Air

Frequently Asked Questions on CBSE Class 6 Science Notes Chapter 15 Air Around Us


What is air pollution?

Air pollution is the contamination of the indoor or outdoor environment by any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere.


What are the ways to prevent ‘Air pollution’?

1. Reduce unnecessary usage of vehicles.2. Elimate fireplaces in houses.3. Avoid burning lawns and leaves and use other methods for cleaning.


What is the nitrogen cycle?

The nitrogen cycle is the biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among the atmosphere, terrestrial and marine ecosystems.


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