Air pressure is the amount of air being forced against a surface. It’s the reason why planes, birds and insects fly. It’s the reason why balloons and bubbles float.
In outer space, where there is no air, astronauts have to wear pressurized space suits that push against their bodies with the same forces as the air on earth.
Without air we can not live.
We cannot see it or smell it, but we can feel it when it moves. Just like water, air has many uses.
Sailing boats have large sails which catch the wind to push them through the water.
Windmills harness the power of the wind to grind wheat into flour or make electricity.
Meteorologists use barometers to measure this atmospheric pressure (also called barometric pressure). At sea level the atmospheric pressure is approximately 1 kilogram per square centimeter (14.7 pounds per square inch), which will cause a column of mercury in a mercury barometer to rise 760 millimeters (30.4 inches).