Adiabatische processen voor een ideaal gas

A thermodynamic process with no heat transfer inside or outside the system is termed adiabatic.

Thus, according to the first law of thermodynamics, the change in internal energy is the negative of the work done in an adiabatic process.

For instance, a fire piston consisting of a thermally insulated tube has one end closed, and the other end has a movable plunger. 

If a small piece of cotton ball is placed inside the tube and the plunger is allowed to push down rapidly at room temperature, the cotton ball catches fire despite no heat being applied. This happens due to adiabatic compression.

Here, as the volume decreases, the work done becomes negative; hence, the internal energy change is positive, with a corresponding increase in gas temperature.

Conversely, when opening a bottle of cooled carbonated drink, the gas trapped in the bottle undergoes adiabatic expansion, resulting in the work done being positive.

As a result, the internal energy decreases with a corresponding temperature drop, condensing the evaporated vapor into a visible cloud.