pascal (Pa)

The unit of pressure in the International System. It is equal to the pressure exerted by a force of one newton (1 N) applied uniformly and perpendicularly over a surface of one square meter. Mathematically, it is expressed as: 1 Pa = 1 N/m². In Meteorology, atmospheric pressure is expressed in hectopascals (hPa). The unit is named in tribute to the French scientist Blaise Pascal (1623-1662), who, among his numerous contributions in the fields of mathematics and natural history, was notable for his studies on the pressure exerted by fluids. He was the first to demonstrate that atmospheric pressure decreases with altitude.