This document defines several key concepts relating to gases: Natural laws describe consistent observed behaviors in nature, such as the law of conservation of mass. Boyle's law states that for a fixed amount of gas at constant temperature, volume and pressure are inversely proportional. Charles's law describes how the volume of a fixed amount of gas increases as temperature rises when pressure remains constant. Absolute zero is the temperature at which gases have no volume, defined as 0 K or -273°C. The kinetic theory of gases proposes that gas particles are in constant, rapid motion and far apart relative to their size.