Atmospheric pressure is the weight that the atmosphere exerts upon us. The measured value of the atmospheric pressure fluctuates slightly in response to moving weather systems, and it drops as one ascends to higher elevations, since less air is...

Aristotle, whose teachings sometimes otherwise inhibited the advancement of science, was right on target in his belief that the atmosphere surrounding the Earth had weight. Moreover, Aristotle stated that as air density decreased, it would be possible...

Force per unit area exerted by the air above the surface of the Earth. Standard sea-level pressure, by definition, equals 1 atmosphere (atm), or 29.92 in. (760 mm) of mercury, 14.70 lbs per square in., or 101.35 kilopascals, but pressure varies with...

That exerted by the mass of air acting under gravity at any particular point. Atmospheric pressure generally decreases with altitude, but the pressure also varies according to meteorological conditions and temperature. Standard atmospheric pressure at...

Atmospheric pressure is the pressure at any point in the Earth's atmosphere. In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point. Low pressure areas have...