Understanding Air Pressure also called atmospheric pressure or barometric pressure

Air Pressure results from the weight of a column of air extending from the top of the thermosphere to the surface About 1 kg/cm² or 14.7 lbs/in²

Just like this aquarium example If air pressure was only exerted downward that would squish us!!! But air pressure is exerted in all directions Just like this aquarium example

Measuring Air Pressure A barometer is an instrument used to measure atmospheric pressure When air pressure increases, the mercury in the tube rises

What the barometer tells you When the barometer falls, a low pressure system is moving in. This means cloudy weather (rain). When the barometer rises, a higher pressure system is moving in. Clear weather.

Air flows from areas of higher pressure to areas of lower pressure What is WIND? Wind is the result of horizontal differences in air pressure High Pressure Low Pressure Air flows from areas of higher pressure to areas of lower pressure

Why do air pressures vary? The unequal heating of Earth’s surface generates pressure differences Therefore… Solar radiation is the ultimate energy source for most wind