Well, somebody has finally done it. We’ve created a tractor beam…for water, at least. A team at Australia’s National University in Canberra have figured out a way to create water “beams” they can control, allowing them to move the subject of their experiments—a ping-pong ball—any way they wish.
The team uses a wave generator in order to create the tractor beam, a horizontal device that has tiny plungers on its underside, where it rests on the water. When the device is turned on, the plungers vibrate, creating ripples on the water’s surface that can be used to create inward flows—water “beams” that push the ball toward the generator—or outward flows, which push the ball away, depending on the shape of the plungers.
To test out their theory, the team filled a tank with water before covering its surface with tracer particles, which allowed them to see the directions of the currents they would produce. Using a fast video camera, they were able to record every water movement they created, with each differently shaped plunger, and how fast the movements were.
“We have figured out a way of creating waves that can force a floating object to move against the direction of the wave,” project leader Horst Punzmann said in a press release.
Weirdly, there’s no mathematical theory that can explain the movement they’ve produced in their experiments, but their water tractor beam works wonderfully regardless. Their research, which was published in the newest issue of Nature Physics, could eventually be used to help oceanic disasters: cleaning up or containing oil spills or trash, for instance. They could even be used to manipulate small boats in distress.
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