Reversible process (thermodynamics)

Reversible processes are like a game of tug of war: they can be stopped and started at any time without anything changing - kind of like hitting the pause button on a movie. A reversible process is when something changes and then changes back exactly the same way. An example is when you turn a lightbulb on and off - the lightbulb is the same before and after you turn it on and off. In thermodynamics, this means that energy can go back and forth between two systems (like hot and cold temperatures) without doing any lasting damage.