3 February 2012

OBJECTIVE: Identify the components of air and understand how air pressure changes.

INTRO:•Hand-in Missing Assignments•Write Q&A in notebook:• Have your ears ever popped? • What were you doing that made them pop? • What do you think causes your ears to pop?

Air and Air Pressure

Air and Air Pressure

• Atmosphere

• Air

• Made of air which is made of different gases– 78% = nitrogen– 21% = oxygen– 1% = carbon dioxide,

water vapor and other rare gases

• Pulled down by gravity which creates air pressure

Air and Air Pressure

• Air pressure • The measure of force air molecules push on a surface

• As air molecules are pulled down by gravity, they collide and become squeezed together, that force is air pressure.

Air Pressure Demo

Air and Air Pressure

• High air pressure

• Low air pressure

• Clear skies• More Sun• Less wind• Drier weather• Clouds• Less Sun• More wind• Possibly precipitation

Air and Air Pressure

• isobar • Line drawn on a weather map that connects points of equal pressure

Adobe: Airflow