> A wax motor is a linear actuator device that converts thermal energy into mechanical energy by exploiting the phase-change behaviour of waxes.[1] During melting, wax typically expands in volume by 5–20%
https://en.wikipedia.org/wiki/Wax_motor
> A wax motor is a linear actuator device that converts thermal energy into mechanical energy by exploiting the phase-change behaviour of waxes.[1] During melting, wax typically expands in volume by 5–20%
https://en.wikipedia.org/wiki/Wax_motor