A wax motor is a very powerful linear actuator that is powered by any source of heat, and converts the thermal expansion of wax into a short linear movement.

I cut one from a water valve actuator in half so we could look inside.

Original video:-
   • DO NOT OPEN!  -  (Challenge accepted)  

It's been suggested by Jacob that the copper powder might be to fine tune the amount of expansion to the application. The copper itself will not expand much with heat.

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