What is a gas in physics?

Likewise, when a gas is allowed to expanded into a region of reduced pressure it does work on its surroundings. The energy to do this work comes from the internal energy of the gas and so the temperature of the gas drops. read more

Gas laws, Laws that relate the pressure, volume, and temperature of a gas. Boyle’s law—named for Robert Boyle—states that, at constant temperature, the pressure P of a gas varies inversely with its volume V, or PV = k, where k is a constant. read more

A law relating the pressure, temperature, and volume of an ideal gas. Many common gases exhibit behavior very close to that of an ideal gas at ambient temperature and pressure. read more