Perpetual motion machines are a type of imaginary, energy-producing machine that never needs to be charged or replaced. A closed-cycle water mill was proposed by English physician Robert Fludd in 1618 and is one example perpetuum mobile – otherwise known as “the perpetual mover” which has been captivated people ever since it’s first appearance centuries ago. This kind can’t work because they violate the first law on thermodynamics: namely “energy cannot flow from an area of higher temperature (a gas) into lower ones without giving up some amount of heat.”