# Boyle's law

Boyle's law (also known as the Boyle Mariotte law) is one of the gas laws, and relates the volume and pressure of an ideal gas held at a constant temperature.

The law, expressed in symbols, is:

PV = k

where

V is the volume of gas measured in cubic metres or litres

P is its pressure measured in pascals

k is a constant

To maintain the constant during an increase in pressure of a gas, at fixed temperature, requires that the volume decrease. Conversely, reducing the pressure of the gas increases the volume.

The exact value of the constant need not be known to make use of the law in comparison between two volumes of the same amount of gas at equal temperature:

P1V1 = P2V2

Together with the Law of Charles and Gay-Lussac and Graham's law, Boyle's law forms gas laws, which describes the behaviour of an ideal gas. The three gas laws can be generalized by the ideal gas law.

Boyle's Law is named after the Irish natural philosopher Robert Boyle (1627-1691) who discovered it in 1662. Edme Mariotte (1620-1684) was a French physicist who discovered the same law independently of Boyle in 1676, so this law is often known as Mariotte's or Mariotte Boyle law.

This law is used in basic chemistry.

Boyle's Law (http://www.thescubaguide.com/certification/boyles-law.aspx) at the Scuba Guide. Understanding Boyle's law is an important part of scuba certification; see Boyle's law explained in a scuba context.

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