There's just one problem

There's just one problem.They don't work.Ideas for perpetual motion machines all violate one or more fundamental laws of thermodynamics,the branch of physics that describes the relationship between different forms of energy.The first law of thermodynamics says that energy can't be created or destroyed.You can't get out more energy than you put in.That rules out a useful perpetual motion machine right away because a machine could only ever produce as much energy as it consumed.