Friday, March 19, 2010

Making Water Run Uphill, With Lasers [Water]


Making Water Run Uphill, With LasersResearchers at the University of Rochester have discovered how to make liquid overcome gravity and flow upward along a silicon surface. The essential ingredient, as always: lasers.

The scientists achieved the curious movement by using short laser blasts to carve imperceptible patterns into the silicon sheet. That alone prompts the water molecules to climb upward, without any additional aid:

Unlike a straw, though, there is no outside pressure pushing the liquid up; it rises on its own accord. By creating nanometer-scale structures in silicon, Guo greatly increases the attraction that water molecules feel toward it. The attraction, or hydrophile, of the silicon becomes so great, in fact, that it overcomes the strong bond that water molecules feel for other water molecules.

Thus, instead of sticking to each other, the water molecules climb over one another for a chance to be next to the silicon. (This might seem like getting energy for free, but even though the water rises, thus gaining potential energy, the chemical bonds holding the water to the silicon require a lower energy than the ones holding the water molecules to other water molecules.) The water rushes up the surface at speeds of 3.5 cm per second.

A fun party trick, but are there practical applications? Actually, yes! This could be the first step towards new heat regulation strategies for computers. Instead of fans, we may see liquid cooling systems thanks to silicon that can pump its own coolant. That method would be more energy efficient, cost effective, and most importantly a heckuva lot more lasery.

As has been pointed out in the comments, the image above is an optical illusion and here for illustrative purposes only. [University of Rochester via CrunchGear]