👉 Watterson's law, also known as Watterson's Rule, is a fundamental principle in thermodynamics that describes how temperature changes with respect to pressure and volume. It states that for a given volume of a gas at constant pressure, the amount of heat transferred from one point to another is directly proportional to the change in temperature. This law can be expressed mathematically as: ΔT = ΔU / p where ΔT is the change in temperature, ΔU is the change in