Hovering water droplets zip around like UFOs

Sandrine Ceurstemont, editor, New Scientist TV

It may look like a launch pad for UFOs but the floating objects in this video are actually hovering drops of water. Thanks to a new technique developed by Kripa Varanasi from the Massachusetts Institute of Technology and colleagues, condensing drops of water are able to zip around like pucks on an air hockey table, a behaviour that could be exploited to make industrial condensers more efficient.

To make the drops levitate, the team coated a water-repellent surface of tiny bumps with a lubricant. When water condensed on the untreated surface, it formed droplets that were pinned in place (see video above). But on the thin slippery layer, they zip around at a speed never seen before on a hydrophobic surface.

The high velocity allows condensed droplets to move out of the way so that new ones can form. That could be useful in power plants, where condensers turn steam from generators back into water, and in desalination plants, where condensers are key. By increasing the rate of droplet formation, the new technique should speed up such processes.

The work will be presented next month at the American Physical Society's Division of Fluid Dynamics conference in San Diego, California.

If you enjoyed this post, see how a superconducting disc can be locked in upside-down levitation or watch a nanorocket propel itself through a liquid.

Journal reference: ACS Nano, DOI: 10.1021/nn303867y

Source: http://feeds.newscientist.com/c/749/f/10897/s/24c90013/l/0L0Snewscientist0N0Cblogs0Cnstv0C20A120C10A0Chovering0Ewater0Edroplets0Ezip0Earound0Elike0Eufos0Bhtml0Dcmpid0FRSS0QNSNS0Q20A120EGLOBAL0Qonline0Enews/story01.htm

marian hossa philip humber red sox white sox chuck colson ufc 145 results orrin hatch