Mon Jul 15, 2013, 07:54 PM
n2doc (44,972 posts)
Sound waves can be used to levitate and move objects
By Meeri Kim, Updated: Monday, July 15, 4:15 PM
Scientists have been able to use the power of sound to levitate small items — including insects and fish — for decades. But now researchers from Switzerland have figured out how to move objects around in midair, according to a new study.
The breakthrough in acoustic levitation will allow scientists to unlock “a huge amount of applications for this very powerful method,” including in pharmaceutical and electronics manufacturing, said author and mechanical engineer Dimos Poulikakos of ETH Zurich, a science and technology university in Switzerland.
The study was published online Monday in the Proceedings of the National Academy of Sciences.
Poulikakos’s team performed a number of midair experiments, such as combining water droplets or chemical solutions, inserting DNA into cells and even making a tiny portion of instant coffee. They also levitated a wooden toothpick — something that had never been done before — while rotating it and moving it forward and backward.
Sound waves exert pressure when they hit a surface, but the effects are usually too small to notice. But if the intensity is cranked up high enough, sound has the ability to counteract the effects of gravity.
4 replies, 1450 views
Always highlight: 10 newest replies | Replies posted after I mark a forum
Replies to this discussion thread
Sound waves can be used to levitate and move objects (Original post)
|Xipe Totec||Jul 2013||#2|
|Judi Lynn||Jul 2013||#4|
Response to n2doc (Original post)
Mon Jul 15, 2013, 08:05 PM
siligut (12,272 posts)
1. Just make sure Fido is no where near
Poulikakos and his colleagues used levels of about 160 decibels; that’s louder than standing near a rocket launch and is enough to rupture a human eardrum. But they were able to work without ear protection.
They took advantage of the fact that the frequency of sound — the physical property that gives it a pitch — also matters. Using 24,000 hertz (Hz), a level comparable to a dog whistle, they were unaffected by the noise. The upper range of human hearing is about 20,000 Hz.
Response to n2doc (Original post)
Wed Jul 17, 2013, 04:01 AM
Judi Lynn (112,378 posts)
4. Sound waves can be used to levitate and move small objects
Sound waves can be used to levitate and move small objects
Tuesday, July 16, 2013 - 1:19pm
It seems that levitation without contact is no longer just a cool illusion trick performed by magicians. Scientists at the Laboratory of Thermodynamics in Emerging Technologies in Zurich, Switzerland, have successfully levitated small objects using only sound waves.
Acoustic levitation is better than magnetic levitation in that it can be used on any object, not just materials that are magnetic. The only limitation with acoustic levitation is that the object's diameter must correspond to half the wavelength of the acoustic waves. Although acoustic levitation has been performed before, this new method allows researchers to have full control over an object's movement with a precision not seen in previous studies. With this new technique, the effect is created by static waves that are held in place by a reflector that bounces the wave back upon itself. This causes interference and creates a consistent upwards pressure that can cancel out the effect of gravity on an object placed within its field.
This research means that with enough power, anything could be possibly levitated, even humans. The power required for human levitation, though, would have to be immense, and it's not exactly a guarantee that the human body could survive such forces. The technology needs to be refined in order to prevent a body from exploding (ouch) or serious internal bleeding. The power involved also limits the reality of levitating heavier items, such as a human body. Needless to say, the standard warning applies: do not try this at home.
This new development could be useful on a smaller scale, though. As many biological and chemical processes can be disrupted by contact with a surface, acoustic levitation could provide a solution for working with such materials.
(Short article, no more at link.)