- Air in motion is called wind.
- Air occupies space.
- It is also present in water and soil.
- Our earth is surrounded by a thin layer of air which extends up to many kilometres above the surface of the earth and is called atmosphere.
Components of Air
- Water Vapour– Its presence in air is important for the water cycle in nature.
- Oxygen– Burning can occur only in the presence of oxygen.
- Nitrogen– It is the major part of air but does not support burning.
- Carbon Dioxide– It makes up a small component of the air. Plants and animals consume oxygen for respiration and produce carbon dioxide. Plant and animal matter on burning, also consumes oxygen and produces mainly carbon dioxide and a few other gases.
- Dust and Smoke – Fine hair and mucus are present inside the nose to prevent dust particles from getting into the respiratory system.
Nitrogen and oxygen make up 99% of the air. The remaining 1% is constituted by carbon dioxide and a few other gases, water vapour and dust particles.
- Animals living in water use the dissolved oxygen in water.
- The balance of oxygen and carbon dioxide in the atmosphere is maintained through respiration in plants and animals and by the photosynthesis in plants. This shows the interdependence of plants and animals.
Read More: Chapter 14
