Temperature, altitude and density affect air pressure

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

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

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

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

Barometric Pressure A barometer is used to measure pressure

Mass Does air have mass? How do you know?