Water running uphill a cooling idea

In a phenomenon known as the "Leidenfrost effect," water droplets can perform a dance in which they glide in random directions on a cushion of vapor that forms between the droplets and a hot surface, the American Institute of Physics reported.

A U.S.-Australian collaboration led by Heiner Linke of the University of Oregon found that the droplets can be steered in a selected direction when they are placed on a sawtooth-shaped surface.

The study, published in the Physical Review of Letters, said heating the surface to temperatures above the boiling point of water creates a cushion of vapor on which the droplet floats. The jagged surface appears to redirect the flow of vapor, creating a force that moves the droplet in a preferred direction.

Researchers say they might be able to use this phenomenon to cool off computer processors without adding any additional power.

Copyright 2006 by United Press International