Atmospheric Pressure:

Atmospheric pressure is the amount of air that is pushing down or on you and the earth from all sides. Atmospheric pressure will decrease the higher you are in the atmosphere. Atmospheric pressure is measured using a barometer. Evangelista Torricelli and his assistant Vincenzo Viviani were the scientists who invented the barometer.

Notes from Mrs.Currie. Picture of barometer drawn by: Sloan Allred.