Charles's law

A law discovered by and named after Jacques Charles, but first published by Joseph Gay-Lussac: at constant pressure, the volume of a given mass of an ideal gas is directly proportional to a constant plus its temperature measured on any scale. The value of this constant fixes the zero of the absolute scale of temperature, ie if temperature is given in K then at constant pressure volume is directly proportional to temperature.

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Charles' law (sometimes called the Law of Charles and Gay-Lussac) is one of the gas laws.

The law was first published by Joseph Louis Gay-Lussac in 1802, but he referenced unpublished work by Jacques Charles from around 1787.

The formula for the law is:

-where:

V is the volume. The exact value of the constant need not be known to make use of the law in comparison between two volumes of gas at equal pressure:

.

Charles's Law, Gay-Lussac's Law, and Boyle's Law form the combined gas law. The three gas laws in combination with Avogadro's Law can be generalized by the ideal gas law.