Question

Air escaping from a hose at a gas station always feels cold.Why?

Answer 1

An interesting effect of thermodynamics. As air is compressed in the air compressor, it becomes hot. Heat is lost to the head of the compressor and feed tubing to the storage tank. When the heated, compressed air cools back to room temperature it has lost some of its enthalpy, or thermal energy per unit mass (or volume.)

As the air is released from the hose its pressure quickly reaches atmospheric pressure as it expands. However, since thermodynamics says energy can neither be created nor destroyed, the energy must come from somewhere to drive the expansion…so as pressure drives the expanding gas the gas cools as pressure is traded for volume. In extremes of pressure this cooling (called Joules-Thompson effect) can create ice….or even cause the gas itself to liquify.

Answer 2

Answer:

Air escaping from air hose at a gas station always feels cold. here, the volume of air gas escaping increases and work done is with the expense of internal energy. As internal energy decreases, temperature also decreases.___❤