Science
Related: About this forumScientists Can Levitate Objects Using Sound
As the video points out at the beginning, levitation of objects using sound has been around for a few years. If youve ever stood in front of a large speaker youll know that they can pump out what feels like quite a forceful blast of air as they vibratebut, somewhat deceptively, thats not quite the whole story.
Rather than physically push air out from the speaker, what youre experiencing is a wave of compression moving through the air. The speaker compresses a packet of air, which then rolls through the room, with the size of the compressed air corresponding the wavelength of the sound wave. And, just like sound waves, waves that overlap each other create new waves.
To levitate something just requires creating a standing wave. Think of it like this - if youre watching a sound wave plotted out on a graph, itll be rolling along, going up and down as it oscillates. A standing wave occurs when two or more waves combine to create a new wave where, as the wave oscillates, there are points where theres no movement. Theyre called nodes.
If a speaker outputs a standing wave, in the most basic sense it means that it wont feel like the areas of compression - those blasts of air - are moving. The gaps between those blasts of air will be positions of neutral force, with air pressure pushing in on it from both directions. If you stick an object in there thats light enough, and smaller that the size the gap (which will be the sounds wavelength), the force of the air should keep it floating in a stable position.
Video:
Link: http://www.newrepublic.com/article/116187/scientists-can-levitate-objects-using-sound-waves
DetlefK
(16,423 posts)Water has a higher Reynolds number, so they should be able to manipulate even bigger objects.
yesphan
(1,587 posts)will be the first to roll out this technology for crowd control, etc. ?
Blue Owl
(50,349 posts)n/t