The principle of Boyle’s law is that the volume of gas confined at constant temperature is inversely proportional to the increase of pressure on it; or p1V1 = p2V2, where
p1 = initial absolute pressure, Pa (lb/in.2)
v1 = initial volume, m3 (ft3)
p2 = final absolute pressure, Pa (lb/in.*)
v2 = final volume, m3 (ft3).
For example, this law expresses the fact that if the pressure of a certain volume of gas is doubled, the volume will be reduced to one-half the original volume, provided the temperature remains constant.