The specific heat (C) is critical because it determines how quickly a substance will heat up or cool down. It is a quantity of heat that is required to change the temperature of 1 kilogram of a substance by 1 degree Celsius. Specific heat capacity is a quantity central to the thermodynamic analysis of a substance.

In this experiment, the pressure was the best parameter to monitor and evaluate, and thus an equation relating the specific heat and the two pressure readings had to be derived. The derivation required the application of the first law of thermodynamics to the adiabatic expansion process and using the ideal gas law, making an assumption that the air behaves like an ideal gas.

In thermodynamics, an isentropic process is a process that takes place from initiation to completion without an increment or decrement in the entropy of the system. In other words, the entropy of the system remains constant. Entropy is a form of energy.

If a process is both reversible and adiabatic, then it is an isentropic process. An isentropic process is an idealization of an actual process and serves as a limiting case for an actual process. For an adiabatic process, there is no transfer of heat energy.

Before the experiment, the atmospheric pressure, P2 was measured using the barometer so as to determine the absolute pressures of the cylinder. In a similar way, the room temperature T1 was measured using the mercury in a glass thermometer.

The vessel was gradually pressurized to 5psig and the air supply turned off followed by the closing of the valve in order to isolate the compressed air inside the tank.&nbsp.