Polytropic Expansion of Air Object The object of this experiment is to find the relation between pressure and volume for the expansion of air in a pressure vessel – this expansion is a thermodynamic process. Introduction The expansion or compression of a gas can be described by the polytropic relation , where p is pressure, v is specific volume, c is a constant and the exponent n depends on the thermodynamic process. In our experiment compressed air in a steel pressure vessel is discharged to the atmosphere while the air remaining inside expands. Temperature and pressure measurements of the air inside the vessel are recorded. These two measurements are used to produce the polytropic exponent n for the expansion process….