Japanese Scientists Levitate, Move Objects in Mid-Air Using Sound Waves

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Some scientific feats haunt the human imagination, driving decades of scientists to work toward them even if their practical effects are likely small.

In this case, 3-millimeters small: Japanese scientists have devised a way to levitate objects as big as a small screw in mid-air, moving them not just up and down but also to-and-fro and side-to-side.

Ultrasound, or sound waves whose frequency is higher than a normal human can hear, has a number of scientific and medical applications. As far back as the 1970s, research had shown that small objects can sit in the tiny nodes created by two slightly misaligned ultrasound waves, in seeming defiance of gravity.

But, up till now, experimenters could only move the levitated objects up and down. The Japanese team managed to move the objects in other directions, too, by creating a focal point between four ultrasonic phased arrays. The objects can move anywhere within the area that output of the arrays overlaps.

Neat, right? But the potential applications seem limited. Humans and our stuff are just too big to fit in the nodes between waves, so the method won’t likely lead to levitation as seen in science fiction programs.

But it could lead to a method for controlling objects during space travel, the researchers note. Keeping in mind how difficult it is to control something as straightforward as a snack of mixed nuts, it’s easy to see why space agencies and the growing pack of space exploration companies would want to muster more control of the items they transport.

Cameron received degrees in Comparative Literature from Princeton and Cornell universities. He has worked at Mother Jones, SFGate and IDG News Service and been published in California Lawyer and SF Weekly. He lives, predictably, in SF.

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