Animation showing the pressure_temperature law in an ideal gas. The dials at right show the pressure P, temperature T and volume V of the gas. The law states that, at a constant volume, an increase in the temperature of a gas causes a proportional increase in its pressure. When the heaters are applied to the box, the particles of gas grey heat up turning red, and travel much more quickly. Their rapid motion causes more frequent collisions with the sides of the container, which is seen as increased pressure. The law is attributed to Jospeh Louis Gay_Lussac 1778_1850, but the basic principle had been established some 100 years beforehand by Guillame Amontons 1663_1705. This animation is part of a series on the ideal gas laws. See K003 3525_3530 for the complete set.