perpetual-motion machine

Cultural  

1. A machine that could run forever. A perpetual-motion machine would have to produce at least as much energy as was needed for its operation. According to the second law of thermodynamics, such a machine is impossible, and to date none has ever been successfully demonstrated.

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Example Sentences

His White House was a perpetual-motion machine, reaching into every corner of Washington and beyond.

From The Wall Street Journal

He strung together variations without pause into a frictionless perpetual-motion machine.

From New York Times

Now, if you have systems that spontaneously want to move, this sounds dangerously like a perpetual-motion machine, and that had scared physicists away.

From Scientific American

For instance, thermodynamics tells you that it is impossible to create a perpetual-motion machine.

From Literature

Alas, the plates have to be pried apart again, which requires more energy than was initially produced; most scientists believe that this fact kills the idea of making a perpetual-motion machine that runs on vacuum energy.

From Literature