Consider a weather balloon filled with helium gas having some initial pressure and volume rising and expanding adiabatically to a final volume under decreasing atmospheric pressure. What is the work done by the gas? If the initial and final temperatures are known, then, for an adiabatic process, the work done is obtained from its internal energy, expressed in terms of temperature change. Another way is using the condition for the adiabatic process, from which the gas's initial and final pressures and volumes can be related. The terms are rearranged for simplification. Recall the work during the volume change and substitute the obtained pressure expression in it. By integrating this expression with the volume change, the work done during an adiabatic process can be determined. If the initial gas pressure in the helium balloon is 1 atm, and the balloon's volume changes from 25 m3 to 100 m3, then by substituting the known quantities in the derived expression, the work done by the gas can be calculated.