What is Atmosphere, Air & Atmospheric Pressure | Geography notes for UPSC

What is Atmosphere?

Atmosphere is a blanket of gases which surrounds the Earth. It is one of the four components of the Earth’s ecosystem. The other three are biosphere, hydrosphere and lithosphere. Without the atmosphere there will be no life on Earth. Nitrogen, Oxygen and Argon are the three major gases that exists in the atmosphere.

What is Air Pressure?

The weight of air molecules exerting pressure on a particular object or thing is called as Air pressure. The air in the tire in your car is under pressure due to the weight of the car and the surface tension of the tire. Air pressure It can be measured by pressure gauge. It can be changed.

What is Atmospheric Pressure?

Atmospheric pressure is also called barometric pressure, which force per unit area exerted by an atmospheric column. Atmospheric column is the weight of the air above per unit area of the surface. Atmospheric pressure changes as the height or altitude increases. The highest pressure is at sea level and the lowest pressure is at the end of troposphere.

Atmospheric pressure is around us all of the time. The air you are breathing has weight, and although it doesn’t weigh a lot, there is a lot of it around. Atmospheric pressure. It is measured by barometer. It cannot be changed.

Barometers is used by the  meteorologists to measure the pressure of air. The Barometric pressure reading is given either in inches of centimeters. The movement of the mercury column in the barometer determines the pressure. It moves upward or downward. Readings of barometric pressure are taken by looking at the markings on the outside of the glass cylinder. Barometers are calibrated with inches or centimeters.

 

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