|Over balanced wheel|
What does perpetual motion machine mean?
a machine that can continue to do work indefinitely without drawing energy from some external source; impossible under the law of conservation of energy.
The history of perpetual motion machines dates back to the Middle Ages. For millennia, it was not clear whether perpetual motion devices were possible or not, but the development of modern theories of thermodynamics has indicated that they are impossible. Despite this, many attempts have been made to construct such machines, continuing into modern times. Modern designers and proponents often use other terms, such as "over-unity", to describe their inventions.