What is pressure?
Pressure is FORCE over AREA.
In the image below, both have the same area, but A has more force, so
it would also have more pressure.
A
B
What is AIR pressure?
Air Pressure is the force exerted on a surface by the weight of the air
above that surface.
Different factors can cause changes in air pressure.
PRESSURE
AIR
GROUND
How does AIR pressure
relate to gases?
PRESSURE
The more gas
molecules per
given unit of area,
the greater the air
pressure.
Higher pressure
How does AIR pressure
relate to altitude?
PRESSURE increase
High
altitudes
Typically, as altitude
increases, air
pressure decreases
Low
altitudes
What causes changes in air
pressure?
Aside from altitude, Changes in air pressure are driven by solar
radiation, which is unequally distributed across the globe.
What causes changes in air
pressure?
Changes in air pressure are driven by solar radiation, warm air rises
and as a result becomes dispersed and less dense. Cool air falls is
heavier/more dense and falls towards the ground.
Warmer- Less
dense, RISES
Cooler- more
dense, Falls
Why do changes in air
pressure matter?
Changes in air pressure results in the movement of air. Air moves from
areas of high pressure to areas of low pressure until a balance is reached.
L
H
Why do changes in air
pressure matter?
Wind is the result of HORIZONTAL differences in air pressure.
L
H
WIND