Reinventing the

Square Wheel

Why build an unworkable device? Every basement tinkerer has probably built at least one device that didn’t work as expected. One can learn a lot from such failures, because they teach us the pitfalls of design, the limitations of materials, and the restrictions imposed by nature’s laws. It’s easy to superficially examine a drawing or blueprint of a device, and glibly say, “That will never work.” It’s quite another thing to reason out exactly why it doesn’t work, and one can gain even deeper insight from hands-on manipulation of the recalcitrant mechanism.

PERPETUAL FUTILITY

When people say, “It’ll never work,” they may sometimes be right. Most new ideas turn out to be wrong and are swept under the rug of history. But even wrong ideas can be useful because they give us valuable information about what doesn’t work, and narrow the field of things we might try that could work. Unfortunately, some people never give up on a discredited idea. Such is the case with the perennial search for perpetual motion. Even today ^{One of Bhaskara’s wheels} some “perpetual motionists” firmly believe it is possible, devoting considerable time and money to their attempts to achieve it.

Early Attempts at Perpetual Motion

A perpetual-motion device is easier to define than to make. It is a wheel that continues its motion — undiminished — forever, without input or output of energy. Even better would be a machine that continues its motion indefinitely while continually putting out additional useful power (output power greater than input power). Hopeful inventors call this an over-unity machine, because it would have a power efficiency greater than 1. If some of its output were used to power the input, it would require no fuel, but would simply continue doing useful work. Needless to say, no such machines have ever been successful, or we would not have an energy crisis.

Perpetually turning wheels were described in Sanskrit treatises in the fifth century, and later by

Villard de Honnecourt’s wheel

Top illustration by Hans-Peter Gramatke

70 Make: Volume 09