The thin layer of air surrounding the earth is called Atmosphere. It consists Oxygen, Nitrogen, Carbon dioxide, water vapour, dust particles etc. Based on chemical composition atmosphere can be divided into two layers. They are:
1. Homosphere
2. Heterosphere
Based on density and temperature Atmosphere can be divided into:
1. Troposphere
2. Stratosphere
3. Mesosphere
4. Thermosphere
5. Exosphere