Air Pressure

What is Air Pressure? The weight of the air pushing down on us and everything else around us. Happens because of the gravitational pull.

Air Pressure Why doesn't all that pressure squash me? Air pushes on you with a force of 14.7 pounds per square inch. The force on 1,000 square centimeters (a little larger than a square foot) is about a ton! Why doesn't all that pressure squash me? Remember that you have air inside your body too, that air balances out the pressure outside so you stay nice and firm and not squishy.

ELEVATION Low pressure High pressure Higher elevation = lower pressure Lower elevation = higher pressure Low pressure High pressure

HIGH & LOW PRESSURE SYSTEMS Warm Moist Rising air Counterclockwise rotation HIGH PRESSURE Cold Dry Sinking air Clockwise rotation

Compare Warm Air and Cold Air Warm, moist air = lower pressure (lighter) Molecules spread out; Fewer molecules in a certain space WARM AIR Cold, dry air = higher pressure (heavier) Molecules crowd together; More molecules in a certain space COLD AIR

How does air pressure relate to weather? Helps to determine if there will be rain or sunny skies; cold or hot air; etc…

Low Pressure systems Warm Humid Rainy Cloudy weather Thunderstorms Severe weather The warm air rises, condenses, forms clouds and rains!

Low Pressure Weather Results

High Pressure systems Sunny skies Cooler temperature Dry air Beautiful weather

High Pressure Weather Results

Front Animations Cold Front Warm Front Stationary Front Occluded Front

Your Turn!!! Now YOU are going to demonstrate air pressure by doing a Metal Can Experiment!!