What Is Boyle's Law?

Boyle’s law describes the relationship between volume and pressure in a fixed mass of gas at a constant temperature. It states that the pressure of a gas is inversely proportional to the volume of a gas at a constant temperature.

Boyle’s law was first stated by Robert Boyle to describe the relationship between volume and pressure for ideal gases. An ideal gas is a theoretical gas, where the individual gas molecules have only mass, no volume and do not interact with each other except during collisions. In ideal gases, the pressure varies inversely to changes in volume. For example, if the volume is doubled, the pressure is halved. This is because when the volume increases, the ideal gas molecules have more space to move and collide less with the walls of the contained, thereby exerting a smaller pressure.

The relationship between pressure and volume as described by the law can also be expressed as a formula, P1V1 = P2V2, where P1 and V1 are the initial pressure and initial volume, while P2 and V2 are the final pressure and final volume, respectively.

In real gases, the relationship between changes in volume and pressure at a constant temperature is not as linear as described for the ideal gas, however the law still applies.