ICSE Class 9 Answered

The concept of air pressure:

Air has mass, so it exerts pressure on any surface or organism that comes into its contact. This is known as air pressure. Air pressure decreases as we move away from the surface of the Earth. Thus, it decreases with an increase in altitude or height. It also decreases with an increase in temperature. Winds are caused due to differences in air pressure. As warm air is light, it rises, cools down and then spreads. Once it cools down, the air starts to sink back to the Earth. When the warm air rises, low pressure area is created and when the air sinks, an area of high pressure is created.

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