FiReaNGeL writes "Could humans one day walk on walls, like Spider-Man? A palm-sized device invented at Cornell that uses water surface tension as an adhesive bond just might make it possible. The device consists of a flat plate patterned with holes, each on the order of microns (one-millionth of a meter). A bottom plate holds a liquid reservoir, and in the middle is another porous layer. An electric field applied by a common 9-volt battery pumps water through the device and causes droplets to squeeze through the top layer. The surface tension of the exposed droplets makes the device grip another surface — much the way two wet glass slides stick together. To turn the adhesion off, the electric field is simply reversed, and the water is pulled back through the pores, breaking the tiny 'bridges' created between the device and the other surface by the individual droplets."