Atmosphere is the thick blanket of air that surrounds the surface of the earth. It is divided into different layers.

(a) Troposphere: It is the first layer of the atmosphere that is just above the surface of the earth. The air that we breathe is present in this layer. This supports life on the earth.

(b) Stratosphere: Above the troposphere lies the stratosphere. It extends up to a height of 50 km. The ozone layer is present in this layer. Airplanes fly in this layer.

(c) Mesosphere: This is the third layer of the atmosphere. It lies above the stratosphere. It extends up to the height of 80 km. Meteorites burn up in this layer on entering from the space.

(d) Thermosphere: In thermosphere temperature rises very rapidly with increasing height. Ionosphere is a part of this. This layer helps in radio transmission.

(e) Exosphere: The upper most layer of the atmosphere is known as exosphere. This layer has very thin air.