Perpetual motion machine remains elusive prize

Remember the little glass “drinking birds” that were a craze during the 1950s and ’60s? Seemed like perpetual motion, didn’t it? Well, I guess it was – until all the water evaporated, at which point it required someone’s energy to replenish the liquid.

For centuries, dreamers, inventors and charlatans have been searching for “perpetual motion,” or a machine that, once started, will run forever while generating enough power to not only run itself, but do useful work besides. So far, no one has actually come up with such a machine, but someone is always trying to get something for nothing, especially when it comes to