Japanese Scientists Use Sound To Levitate Objects And Manipulate Them Midair [VIDEO]
"Acoustic manipulation" sounds like the name of a bad Prince album, but in fact it's an incredibly cool way to levitate things using speakers. Various kinds of acoustic levitation have been around since the 1970s, but a new method developed by Japanese scientists allows for not only the levitation of an object, but the ability move it around laterally as well. The levitation is created using phased arrays, or speakers, that create standing waves, which are waves that remain in a constant position.
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"The essence of levitation technology is the countervailing of gravity," write the University of Tokyo scientists. "It is known that an ultrasound standing wave is capable of suspending small particles at its sound pressure nodes and, so far, this method has been used to levitate lightweight particles, small creatures, and water droplets....In the present study, we considered extended acoustic manipulation whereby millimeter-sized particles were levitated and moved three-dimensionally by localized ultrasonic standing waves, which were generated by ultrasonic phased arrays."
Watch the video below and you'll see exactly what that translates to. The bottom speaker levitates the object, trapping it in the air--the same old trick that scientists have done for decades--but it is the addition of the side speakers that allow the objects to be manipulated laterally into an air ballet using external controls. What's more, the system uses ultrasonic 40 kHz speakers, so it's also a silent ballet (unless you're a dog).
While right now the whole thing looks more like a neat party trick, the scientists will next try to see how they can use acoustic levitation to manipulate larger objects. There might even be possible applications in space if the technology can be adapted for low gravity. "It has not escaped our notice that our developed method for levitation under gravity suggests the possibility of developing a technology for handling objects under microgravity," the scientists write [PDF].
The University of Tokyo scientists write about their acoustic levitation method in the article "Three-dimensional Mid-air Acoustic Manipulation by Ultrasonic Phased Arrays," published in arXiv, a science research site run by Cornell University.
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