Which gas law explains the expansion of gases upon heating?

The expansion of gases upon heating is best explained by Charles's law. This law states that at constant pressure, the volume of a gas is directly proportional to its absolute temperature (in Kelvin). In simpler terms, as you increase the temperature of a gas, its molecules gain kinetic energy, leading to increased movement and greater separation, which causes the gas to expand.

When a gas is heated, the increase in temperature results in increased volume if the pressure remains unchanged, illustrating the fundamental relationship described by Charles's law. This principle is critical in understanding how gases behave under thermal changes, which is vital in various applications such as engines and climate science.

Other laws, such as Boyle's law, focus on pressure and volume relationships at constant temperature, Avogadro's law deals with the volume of gas in relation to the amount of substance at constant temperature and pressure, and Graham’s law addresses the rates of effusion and diffusion of gases based on their molar masses. These principles have their specific contexts, but they do not directly explain the expansion of gases upon heating as effectively as Charles's law does.