Potential energy & Kinetic energy:
Note:
The spring of a watch stores elastic potential energy.
When a watch is wound, the spring's shape changes and stores potential energy.
This potential energy is converted to kinetic energy when the spring is released and unwound, which transfers energy to the watch's moving parts.
The amount of energy stored in a spring is proportional to how much it's stretched or compressed.
The watch's mechanism, uses the energy stored in the spring to provide a continuous estimate of rotation for a period of time.