Atmosphere : It is the vast expanse of air surrounding the Earth, within which all weather phenomenon occurs.
Composition of Atmosphere
- 78.03% of the total volume of the atmosphere
- Gaseous Nitrogen was discovered by Rutherford. It was initially called Rutherford.
- Since Nitrogen constitutes the largest proportion of the atmosphere, the phenomenon such as pressure, force of winds and reflection of light is largely due to Nitrogen.
- Properties : No colour, No odour, No taste, Prevents quick burning
- Importance : generates protein which is essential for the natural growth of plants and animals and also human beings
- Commercial usage : nitrogenous fertilizers
- 20.99% of the atmosphere volume.
- Importance : Life giver as it is essential for respiration, fuel combustion, provides base to industries
- It enters the atmosphere due to radio active breakdown of potassium within surface rocks
- The rate of formation is very slow
- It is an inert gas
Carbon di Oxide :
- It was the first gas to be studied
- 0.03% in the atmosphere
- It is the heaviest gas
- It is confined to ower layers
- Importance : growth of vegetation, green house effect, asphyxiant gas
- Properties : colourless, odourless, naturally occuring in atmosphere, groundwater,etc, water soluble
- It is used in fire extinguishers, for oil recovery, as a refrigerant and also for coal bed methane recovery
Other major components of the air: Neon Helium Methane Krypton Hydrogen Water vapor (variable percentage)
LAYERS OF ATMOSPHERE BASED ON COMPOSITION OF CONSTITUENTS
It is the thin layer, in which most of the atmospheric processes take place. According to the concentration of the gases, atmosphere is divided into:
- Homosphere: the lower part of atmosphere, upto the height of 90-100 kms. The proportion of gases is homogenous throughout the zone, hence the name ‘homosphere’. Main constituents are nitrogen and oxygen. However, the natural homogeneity is nowadays being disturbed by the economic activities of mankind.
- Heterosphere: It extends from 100 kms. to the outer limits of atmosphere. Here the layers vary largely in their physical and chemical properties.
Importance of Atmosphere
- Base of life
- All the phenomenon concerning weather and climate
- Heat balance
- Protection against sun’s harmful Ultra violet rays through the Ozone layer
Ionosphere layer helps in radio broadcasting.