From Simple English Wikipedia, the free encyclopedia
Atmospheric pressure
is a force in an area pushed against a
surface
by the weight of the
atmosphere of Earth
, a layer of
air
. The air is not distributed evenly around the globe. It moves, and at different times, the layer of air is thicker in some places than in others. Where the layer of air is thicker, there is more air. Since there is more air, there is a higher
pressure
in that spot. Where the layer of air is thinner, there is a lower atmospheric pressure.
At higher
altitude
, the atmospheric density and pressure are lower. This is because high places do not have as much air above them, pushing down.
Barometers
can be used to measure atmospheric pressure for
meteorology
.
[1]
There is the same atmospheric pressure from all directions. The
SI
unit for pressure is
hPa
. Other units such as
Bar (unit)
and torr are used for various applications.