BACK TO PREVIOUS PAGE

Atmospheric Pressure

Atmospheric Pressure. The pressure exerted by the earth's atmosphere at any given point. The standard or normal atmospheric pressure (at sea level) is equivalent to the pressure produced by a column of mercury 29.9 in. (760 mm) high. This pressure decreases at higher elevations and with changing weather patterns (high or low pressure systems). Water boils at 212¦F (100¦C) at normal atmospheric pressure and at somewhat lower temperatures as the pressure is reduced.