Adiabatic Process
A process in which no heat is exchanged between the system and its surroundings.
Formula / equation
q = 0, ΔU = w
Unit
J
In depth
With no heat flow, any work done comes entirely at the expense of internal energy, so adiabatic expansion cools a gas and compression heats it. Adiabatic conditions are approached by insulating the system or by making the change fast enough that heat has no time to flow.
Examples in the real world
Air heating in a diesel engine's compression stroke; a rising air parcel cooling and forming cloud.