Adiabatic expansion is a process in which a gas expands without exchanging heat with its surroundings. During this process, the gas does work on its environment, causing its temperature to decrease. This phenomenon is often observed in thermodynamics and is essential for understanding how gases behave under different conditions. In an adiabatic process, the internal energy of the gas decreases as it expands, leading to a drop in temperature. This concept is crucial in various applications, including refrigeration and engine cycles, where efficient energy transfer is necessary for optimal performance.