Dr Horst Pumzmann (left) and Professor Michael Shats. Photo by Stuart Hay.

Dr Horst Pumzmann (left) and Professor Michael Shats. Photo by Stuart Hay.

Science fiction turns fact

When two ANU physicists created a tractor beam on water, science fiction fanatics across the world rejoiced. ANU Reporter explores the facts behind the recent discovery.

Mention the phrase 'tractor beam' to a Star Wars fan and they will regale you with a quote from Han Solo or explain to you how tractor beams were used to help guide spacecraft into a safe landing.

Science fiction has a strong record for predicting future trends and a group of ANU physicists could be added to the list after they created a tractor beam on water.

This new technique could be used to confine oil spills, to manipulate floating objects or to explain rips at the beach.

The group from the Research School of Physics and Engineering discovered they can control water flow patterns with simple wave generators, enabling them to move floating objects at will.

"We have figured out a way of creating waves that can force a floating object to move against the direction of the wave," Dr Horst Punzmann, who led the project, says.

"No one could have guessed this result."

This ground-breaking technique gives scientists a way of controlling things adrift on water in a way they have never had before, resembling tractor beams that draw in objects in science fiction stories.

Using a ping-pong ball in a wave tank, the group worked out the size and frequency of the waves required to move the ball in whichever direction they want.

Advanced particle tracking tools, developed by team members Dr Nicolas Francois and Dr Hua Xia, revealed that the waves generate currents on the surface of the water.