Air pressure

Air heaviness, also known as atmospheric pressure, refers to the burden of the Earth's atmosphere imperative down on everything at the surface.

A barometer in units called millibars. Most barometers used mercury in glass column, like thermometer, to measure the make over in air pressure.

When the weather condition is calm, the mercury in the barometer not often moves more than half-an-inch under the 30-inch mark.

Atmospheric pressure varies to some extent over the earth surface, and variations in pressure are dependable for the weather that we are so memorable with. Low pressures are associated with storms, tornadoes, and hurricanes.

Relative dampness is the quantity of humidity the air can hold before it rains.

The weight imperative down on a one square-inch sample of air at sea level is 14.7 pounds, which is corresponding to a column of mercury 29.92 inches in height.