A U.S. graduate student won second place in a "Greener Gadgets Conference" competition inventing a floor lamp powered by gravity.

Clay Moulton of Springfield, Va., who received his master's of science degree last year from Virginia Tech, created the lamp as a part of his master's thesis. The LED lamp, named Gravia, is an acrylic column a little more than 4 feet high. The entire column glows when activated by electricity generated by the slow, silent fall of a mass that spins a rotor.

The light output of 600-800 lumens lasts about four hours.

To "turn on" the lamp, the user moves weights from the bottom to the top of the lamp and into a mass sled near the top. The sled begins its gentle glide down and, within a few seconds, the LEDs are illuminated.

"It's more complicated than flipping a switch," said Moulton, "but can be an acceptable, even enjoyable routine, like winding a beautiful clock or making good coffee."

Moulton estimates Gravia's mechanisms will last more than 200 years.

A patent is pending on the Gravia lamp.

Copyright 2008 by United Press International

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