Air Pressure (Lauren)


Sources:

http://kids.earth.nasa.gov/archive/air_pressure/
http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/circulation/air_pressure_p_1.html
http://science.howstuffworks.com/hot-air-balloon5.htm
http://www.hotairballoons.com/hotairballoon-air-science.asp