Why don't perpetual motion machines ever work?
15,728,018 views | Netta Schramm • TED-Ed
Perpetual motion machines — devices that can do work indefinitely without any external energy source — have captured many inventors' imaginations because they could totally transform our relationship with energy. There's just one problem: they don't work. Why not? Netta Schramm describes the pitfalls of perpetual motion machines. [Directed by TED-Ed, narrated by Addison Anderson].