When a gas under a high pressure in a piston (isolated from surrounding is allowed to pass through a valve), why does its temperature decrease once during expansion?
I haven't still studied thermodynamics but would like to know why exactly the temperature decreases.
Is it because under high pressure the heat was concentrated under small volume once expanded the heat is distributed?
Once the gas molecules are allowed to expand through the valve its kinetic energy increases. Where is the source of energy coming from, is it from its internal energy?