Question

Opening a container of compressed gas will allow the gas molecules to escape into the air and cause the container to cool as a result. Why does this cause the container to lose heat energy and feel cooler?

Answer 1

Travelling along this pressure gradient, the gas expands and does work, and this removes energy from the gas. The cold temperature profile sneaks back towards the can, because the air is such a lousy conductor of heat, so the heat is all coming from the can.