1. Temperature, altitude and density affect air pressure

2. Temperature -Heated air
Molecules are far apart
Move with great speed
Less dense than cold air
Exert less pressure
WARM AIR RISES!

3. Temperature-Cold Air Molecules are close Move at a slower speed
More dense than hot air
Exerts greater pressure
COLD AIR SINKS!!!

4. Altitude Air pressure decreases with an increase in altitude.
Fewer molecules as we gain altitude
(Think of people trying to breath on Everest)

5. Density The more dense air is , the more pressure it exerts.
The more molecules it has, the more dense it is.
Water vapor is less dense than other gases, so the more humid, the less pressure
Density decreases as altitude increases

6. Barometric Pressure
A barometer is used to measure pressure

7. Mass
Does air have mass?
How do you know?