Canadian scientists have discovered how to generate electricity - by nothing more than pushing water through a fine glass tube.
As water passes through the tube, tiny amounts of glass - itself a supercooled liquid - 'dissolve' into the water. That gives the surface of the tube a positive charge, which attracts negative ions in the water. The flow of the water carries the positive ions onward, resulting in a net difference in charge between the two ends of the tube. That difference amounts to a voltage of around 10V.
Connect both ends of the tube to a circuit, and the voltage drives a current, albeit a tiny one: only one thousandth of an amp, reports University of Alberta Professor Larry Kostiuk, leader of the team that made the discovery in the Journal of Micromechanics and Microengineering today.
Team member Daniel Kwok is credited with laying the ground work for the team's findings.
The team produced electricity using gravity to push the water through the tube. At a height of 30cm the water column pulled through the tube this way was enough to light a low-power bulb.
That's not enough to do any real work, but by assembling thousand of tubes together, this 'electrokinetic' technique could be used to generate useful amounts of electricity. Kostiuk told The Times that he doubts the technique will replace other forms of electricity generation, but he believes it may well one day prove useful as a way of powering microengines or recharging small electronic devices such a cellphones. ®