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Science

Scientists Use Sound Waves To Levitate, Move Objects 78

Posted by samzenpus
from the they-like-to-move-it-move-it dept.
sciencehabit writes "The tragic opera Rigoletto may move you to tears, but here's a more literal application of the moving power of sound. Sound waves with frequencies just above human hearing can levitate tiny particles and liquid droplets and even move them around, a team of engineers has demonstrated. The advance could open up new ways to handle delicate materials or mix pharmaceuticals."
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Scientists Use Sound Waves To Levitate, Move Objects

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  • Just for the record all Opera moves me tears, what the fuck is up with the middle school rhetorical flourish?

    Also this is basically decades old. How much is /. getting for the clicks?

  • by Anonymous Coward

    Acoustic levitation is nothing new, what they've done is found a way to move stuff around while it's levitating.

    And here's a decent link for those who don't feel like contributing to someone's page counter.

    http://www.pnas.org/content/early/2013/07/10/1301860110

    • by ackthpt (218170)

      Acoustic levitation is nothing new, what they've done is found a way to move stuff around while it's levitating.

      And here's a decent link for those who don't feel like contributing to someone's page counter.

      http://www.pnas.org/content/early/2013/07/10/1301860110

      I move things around on a regular basis, but only when I have a ready supply of beans.

  • Can the bottom of my car be a flat surface which vibrates sprayed water droplets, thus slightly levitating the vehicle and allowing forward movement via those particles?

  • by Grog6 (85859) on Monday July 15, 2013 @05:58PM (#44289615)

    Sand on a 15" speaker, an amp, and a signal generator was a fixture of Hamfests in the 70's.

    Ever notice how sliding a desk across a floor is really heard to do, then gets easier?
    It's because it's levitating part of the mass on trapped sound waves under the sliding feet...

    This is old news by now.

    • by Anonymous Coward

      Yeah i'm pretty sure it's not sound that helps you move desks.
      Once you overcome static friction it becomes easier because sustaining an objects speed at x is less energy intensive than accelerating it from 0 to x.

    • by slew (2918)

      Ever notice how sliding a desk across a floor is really heard to do, then gets easier?
      It's because it's levitating part of the mass on trapped sound waves under the sliding feet...

      I don't think so. I think the desk is an example of Stick/slip [wikipedia.org], not sound wave levitation...

      Of course this acoustic levitation stuff isn't new, every few years someone comes up with crap like this [livescience.com]... Or somehow suggests that similar standing sound waves which cause sonoluminescence [wikipedia.org] can be used for stuff like cold fusion.

    • Ever notice how sliding a desk across a floor is really heard to do, then gets easier? It's because it's levitating part of the mass on trapped sound waves under the sliding feet...

      This is old news by now.

      What? It has nothing whatsoever to do with sound waves, but rather the fact that the coefficient of static friction is higher than that of kinetic friction.

      When you are stationary, you are working against static friction. Once you are moving, however, you are doing work against kinetic friction, which is a weaker force for most substances.

    • by gnomff (2740801)
      From TFA:

      Poulikakos's team spent 4 years trying to budge their floating droplets from a standstill. Finally, they conceived of a chessboard-style setup with multiple vibrating plates, each generating its own sound frequency. By varying the frequency that each plate emits, they can move the acoustic field and the object trapped inside. Their new design, described online today in the Proceedings of the National Academy of Sciences, can precisely control the lateral movement of liquid droplets while keeping them floating smoothly in midair.

      Its the lateral movement and fine control that's new, not the levitation.

    • by Sockatume (732728)

      ...which TFA acknowledges:

      Sound waves don't discriminate, however, and physicists worked out the basic principle of "acoustic levitation" nearly a century ago. A vibrating plate generates a sound wave that bounces against another surface to create a stable standing wave. The points of lower pressure in this static pattern can trap a particle. Scientists have learned how to hold increasingly heavy particles including superdense iridium and even liquid droplets in this acoustic sweet spot.

      But until now, that

  • Back in the 1990s I heard the use of sound waves to move objects proposed as one of the fringe theories for how the pyramids were built, because "people could not have moved those great big blocks such long distances!". So, there must have been earlier work by scientists in moving things with sound waves that crank historians could twist for their own theories.
    • Back in the 1990s I heard the use of sound waves to move objects proposed as one of the fringe theories for how the pyramids were built, because "people could not have moved those great big blocks such long distances!".

      In other news, bumblebees cannot fly.

  • Some people might think this sort of discovery will vindicate claims made by dubious inventors like Keely. Be on the look out for anyone here mentioning "vibratory sympathy".

  • by Megahard (1053072) on Monday July 15, 2013 @06:16PM (#44289813)

    The sound levitated the cat about 2'.

  • by thewils (463314) on Monday July 15, 2013 @06:22PM (#44289859) Journal

    Just play any, for example, Justin Bieber tune and the resulting sound waves instantly move me out of the room. Most commercials on TV work the same way, unless I'm in control of the remote.

  • When will they turn screws using sound?

    • by feufeu (1109929)
      Check. "Unscrew these screws !" to any sufficiently technically literate subordinate will do.
  • Many sounds make things move, for example, the sound of my wife reminding me of chores usually gets me moving pretty swiftly.
  • ...even be able to image human foetuses.
    Sorry -- just thinking out loud.

  • But can it levitate a frog? http://www.youtube.com/watch?v=A1vyB-O5i6E [youtube.com]
  • by Anonymous Coward

    And here I was worried the new owners wouldn't understand the readership when DICE bought /.

  • of when I use my "these aren't the droids you're looking for" sound/hand wave to levitate flies. They shoot straight off. Unfortunately, flies have a very short memory, and two seconds later they're back for more. Definitely too short to be stormtroopers, flies.
  • Who cares? $800 dollar Honda Civics have been doing this with $2500 dollar strereo systems in my neighborhood for years!

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