This acoustic levitation video might just leave you with a new appreciation for finely tuned speaker setups. Not because they can play Led Zeppelin so loud the results register on the Richter scale, but because, when perfectly calibrated, the sound waves they produce are capable of helping objects defy gravity.
A YouTube video of the technique uploaded by researchers in Japan earlier this week shows sound waves levitating light materials like match heads, small screws, and transistors.
The mesmerizing experiments -- conducted by Yoichi Ochiai and Jun Rekimoto of the University of Tokyo, and Takayuki Hoshi of the Nagoya Institute of Technology -- might look like magic. Yet they actually result from a well-understood physical phenomenon.
In a 2012 article, Scientific American explained:
When the... speakers are precisely aligned, they create two sets of sound waves that perfectly interfere with each other, setting up a phenomenon known as a standing wave. At certain points along a standing wave, known as nodes, there is no net transfer of energy at all. Because the acoustic pressure from the sound waves is sufficient to cancel the effect of gravity, light objects are able to levitate when placed at the nodes.
While materials like water droplets have been successfully levitated using this technique in the past, the Japanese researchers have taken it a step further, using arrays of speakers to move objects through the air.
In an email to The Huffington Post, Ochiai said the team used 285 speakers all tuned to an ultrasonic frequency. The resulting "standing wave," he wrote, "generates the force which counters the gravity."
Using this setup, the researchers could then "change the spatial position of standing waves" by controlling the phased array's focal point, thereby moving the objects in space.
Watch what they've termed "Three-Dimensional Mid-Air Acoustic Manipulation" in the video above.
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