Since normal atmospheric pressure is about 10 5 N/m 2 (or 10 5 Pascals), you would need a mercury column of 0.76 meters (or 760 mm—a common unit for pressure). Using water would require a column ...

MOLINE, Ill. — If you've ever climbed a mountain or taken a ride in an airplane, you know that pressure changes with height. Hikers that work in extreme altitudes have to use techniques to keep ...

When air rises, it expands because air pressure decreases with height. The energy in the air gets spread out over greater volumes and its temperature goes down.