The scientific principle that describes the behavior of gases is known as the ideal gas law, which relates pressure, volume, temperature, and the number of moles of gas through the equation PV=nRT. This law assumes that gas particles occupy negligible space and have no intermolecular forces. In reality, deviations occur under high pressure or low temperature, leading to behaviors described by real gas laws. Understanding gas behavior is vital in fields such as chemistry, meteorology, and engineering, affecting processes involving respiration, combustion, and chemical reactions.