In an adiabatic process, internal energy can change despite no heat flow, as described by the first law of thermodynamics. The equation ΔU = -W indicates that if work is done on the gas (W is negative), the internal energy (ΔU) increases. This results in a rise in temperature of the gas, similar to the effect observed when compressing air in a bicycle pump. Understanding this principle clarifies how work and internal energy are interconnected in thermodynamic systems. The discussion emphasizes the importance of recognizing work's role in energy changes during adiabatic processes.
