Walking water

Droplets of water can "walk" uphill across a surface under their own steam according to Heiner Linke and his colleagues from the University of Oregon in Eugene. The self-propelled liquids could find use as a novel way to keep microprocessors cool and so allow them to run at higher speeds. To get droplets of water and other liquids to walk across a surface, the researchers etched a piece of brass with ratchet-like corrugations and then heated it to well above water's boiling point and exposed it to water. This produces a layer of water vapour, a Leiden frost layer, above the surface that allows a droplet of water to sit "on" the surface and to scoot across it with even the tiniest of applied forces.