Acoustic levitation

[donrobison]

I just went to the coast to coast am site and saw the acoustic levitation demonstration in a video posted on a website that is a supposed to be from a research facility. What the clip showed, there are clips of "acoustic levitation" all over the internet so I omitted a link, is a cup floating in air being supported apparently by sound.

I have just witnessed the supposed phenomenon and have not yet been able to come to a conclusion. The explination for airplane lift or the boyant force incorporates pressure differentials and that is what my understanding of sound is. So I guess it could be possible if a sound wave could establish permanent pockets of differing air pressure, but im not sure summing waves that change over time could produce such an effect.

[aquatus1]

To my understanding, sonic levitation is nothing more than a standard application of greater force underneath an object than the object is exerting due to gravity. One can do the same with lasers. It isn't a particularly efficient form of levitation however. It sounds a little like you suspect it doesn't exist, however, which I don't believe has ever been an issue. Of course, many people who don't understand the technology immediately like to bring up ludicrous stories of ancient civilizations using sound to build pyramids and such, but one can hardly compare a trumpet to a focused sonic generator.

[donrobison]

What is the force and what is exerting it?

[aquatus1]

The force is the sonic waves and the source is whatever speaker is generating it.

[donrobison]

sonic waves are not forces. It is true that sonic waves can make things vibrate, but "sonic waves" or sound does not commonly exert a force. I have never been able to move anything with the power of my voice, and I have experienced very loud noises on occasion, but they have never caused a body to displace. How does sound move things? I am looking for a quantative answer. Sound, gravity, force: these dont answer the how. As Galileo would say they are convienient rhetorical tools used to dismiss the mystery behind the phenomenon.

[aquatus1]

sonic waves are not forces. It is true that sonic waves can make things vibrate, but "sonic waves" or sound does not commonly exert a force. I have never been able to move anything with the power of my voice, and I have experienced very loud noises on occasion, but they have never caused a body to displace. How does sound move things? I am looking for a quantative answer. Sound, gravity, force: these dont answer the how. As Galileo would say they are convienient rhetorical tools used to dismiss the mystery behind the phenomenon.

**sigh**

You're going to make me dig out my old physics books, aren't you?

Okay, let me see how much I can dredge up from memory...Sonic waves can be considered a force, in that they "push", they create movement, in other matter, which is pretty close to the scientific definition of force, that being something which has the effect of pushing or pulling, of creating work. Now, sonic waves do indeed exert a force, in that they are a compressive force that progressively moves through matter, ergo it is exerting force on the matter it is traveling through. You may never have been able to move anything with your voice, but You have probably heard the famous example of an opera singer being capable of shattering a wine glass with her voice. And if you have ever been on site at a demolition, or close enough to a sonic boom, you can most definitely feel the sound trying to displace your body (or the the fluids within, at any rate).

I am having a little trouble understanding why you would consider this explanation a rhetorical tool, and why you think sonic waves don't exist as forces. If you want to try a cheap experiment, go to Radio Shack and buy yourself a piezo-electric buzzer. Use a piece of tin foil, about the size of a quarter, slightly bowled, and place it curve side up on the speaker. By alternating the amount of power to the speaker, you can find the optimum frequency that will cause the foil to levitate. Not a lot, and not dramatically, but definitely levitate.

How does it happen? Well, sound waves are essentially waveforms traveling through matter, in this case air. As the compressive waves travel through the air, it alternately compresses and rebounds as the waves pass through it. Frequency dictates the speed at which these compression and rebound cycles occur. By timing it just right, one can cause the moving air (compressing and rebounding) to strike progressively at the surface of the foil, gradually pushing it upwards.

If you feel that I have dismissed the issue by using rhetorical tools again, feel free to ask questions, and if I don't know the answers, I'll see what I can find for you.

[donrobison]

Gravity, electric, magnetic, strong, weak, are forces. Sound isnt a force. I believe the air molecules hitting the bottom more than hitting the top would cause it to levitate, but I still dont see how the air could be manupliated in that way. I assert that your explination doesnt include a fundamental force. Thats fine many people explain things with centripital, boyant, drag, tension, force, friction, and in this case sonic force, but still they dont really get to the heart of the phenomenon. Try explaining your understanding of the phenomenon using a fundamental force and one of the established laws of physics.

My physics teacher warned us about creating our own physics. I havent ever had to explain anything without newton, einstein, kepler, schoringer, pauli, gauss, bernoulli, etc. Im sorry, but physics that excludes them and their laws is a little dubious to me. No offense intended.

Edited December 1, 2006 by donrobison

[aquatus1]

Gravity, electric, magnetic, strong, weak, are forces.

Well...sure, when talking about quantum physics. About interaction between atoms. But we are talking about moving things with sound. We are talking about macro physics. Incidentally, the fundamental forces of nature are Magnetism, Gravitational, Strong nuclear attraction, and Weak nuclear attraction. Electricity isn't in there.

Sound isnt a force.

Sure it is. A force, when talking about macro physics, can be simplisticly defined as something that results in work (i.e. a push or a pull), or more exactly as "an influence on a body or system, producing or tending to produce a change in movement or in shape or other effects." (according to dictionary.com).

I believe the air molecules hitting the bottom more than hitting the top would cause it to levitate, but I still dont see how the air could be manupliated in that way. I assert that your explination doesnt include a fundamental force. Thats fine many people explain things with centripital, boyant, drag, tension, force, friction, and in this case sonic force, but still they dont really get to the heart of the phenomenon. Try explaining your understanding of the phenomenon using a fundamental force and one of the established laws of physics.

That's beyond my knowledge. I could no more explain to you how the fundamental forces of nature drive acoustic levitation than I could explain to you how the fundamental forces of nature drive an internal combustion engine, despite being able to explain how an internal combustion engine works. Frankly, I don't see why it has any relevance. The fundamental forces of nature apply chiefly to the quantum world. In the macro world, we can observe the results of their effects, but their actual force, the effect they have on individual atoms, has little to do with the force that we are measuring in the macro world. Ask your teacher about the difference between quantum physics and macro physics.

My physics teacher warned us about creating our own physics. I havent ever had to explain anything without newton, einstein, kepler, schoringer, pauli, gauss, bernoulli, etc. Im sorry, but physics that excludes them and their laws is a little dubious to me. No offense intended.

Oh, you want me to drop names? I thought you just wanted to understand the concept.

Let's see...sound propagation was described as pressure waves moving through air by Sir Isaac Newton, in his famous Principia. Any device which moves matter (in this case air) creates a pressure wave. Imagine a giant piston moving a diaphragm upwards. The air above the diaphragm is compressed, creating pressure. Pressure seeks to balance out, so it moves away from the diaphragm wall into the air (you can ask your teacher about calculating gas pressure). This movement away, this pressure wave, is what is generally referred to as "the sound wave". That's sound propagation in a nutshell, brought to us by Newton.

Do you understand the basic force behind where the sound wave is coming from?

Edited December 2, 2006 by aquatus1

[donrobison]

No I dont understand. You ask me to make too many assumptions in your explinations. Write a formal proof starting with some well understood physical law. Descartes said that we sould be skeptical of things that arent as obvious to us as our own existance. Also I just realized your expecting thermodynamic processes to be reversable.

Edited December 2, 2006 by donrobison

[aquatus1]

Write a formal proof starting with some well understood physical law.

Formal proof of what?

Descartes said that we sould be skeptical of things that arent as obvious to us as our own existance.

Do you understand that part of having something be obvious to you involves educating yourself on the subject? And that part of educating yourself on a subject involves learning smaller subjects that eventually lead up to greater subjects?

Meaning that unless you have learned enough of the basics, the more advanced subjects won't be clear to you, even though they are valid.

Also I just realized your expecting thermodynamic processes to be reversable.

Why is that?

[donrobison]

yea, this is getting funny. I wanted evidence or a proof that sound can cause a net force on a body or in other words "sonic levitation". This just isnt an obvious consequence of any laws of physics that I know. It seems you cant provide a proof, so I have nothing to tell you. We seem to be going in circles here.

[aquatus1]

You claim that I haven't provided proof, and I haven't, but then, I haven't really explained anything that required proof, in the sense that their existence was in question. You asked me to use a well understood physical law. Are you questioning that sound propagation exists? You previously claimed that I was asking you to make too many assumptions. Which assumption where you having trouble accepting? That a rising diaphragm would compress the air above it? That the compressed air would seek to return to the same pressure as the environment around it? What do you want, the formula for the mathematical description of a wave of force?

To be perfectly honest, I do not think you know what you are asking for. I think you are trying to play "Stump the judge", but don't realize when you have been given the answer, and are continuing to ask "Why?"

[donrobison]

I do not understand how a wave like sound can cause a body to accelerate, it is not at all evident from any law of physics I know and I dont believe you have enough credibility for me to just assume you are right when you keep asserting "sound is a force". Im asking for a formal proof, or supporting evidence. you have provided neither. Its like I keep asking "how does air decrease the acceleration of a body while it falls", and you keep saying drag force drag force drag force drag force drag force drag force drag force drag force drag force drag force drag force drag force drag force drag force drag force drag force. terms are not adequate explinations. I assume you know how einstein proved the phenomenon of time dilation and length contraction merely with the fact that the speed of light is constant with respect to all frames, and a little geometry I want a proof like that. You couldnt know what I want so dont try to pretend you do. If you cannot provide a proof then thats fine, I dont think I could without many hours of contemplation and much research.

[aquatus1]

I do not understand how a wave like sound can cause a body to accelerate, it is not at all evident from any law of physics I know and I dont believe you have enough credibility for me to just assume you are right when you keep asserting "sound is a force".

You don't have to take my word for it. It's a definition. I even gave you a definition and I sourced it. If you don't believe it, that's up to you, but don't go saying that I am asking you to believe me because I am an authority on the subject. I've made no such claim, and said nothing that cannot be cross-checked very easily with a few minutes on google. If you think I made up the definition I gave you from dictionary.com, by all means, go to dictionary.com and check it. I don't care if you don't think I am credible, but don't pretend that I tried to stand on my non-existent credibility.

Im asking for a formal proof, or supporting evidence. you have provided neither. Its like I keep asking "how does air decrease the acceleration of a body while it falls", and you keep saying drag force drag force drag force drag force drag force drag force drag force drag force drag force drag force drag force drag force drag force drag force drag force drag force.

I'm not going to go into any sort of formal proof if you don't even understand the basics of it. If you do not understand that dropping a ball off a building will cause the ball to hit the pavement below, why the heck would I start talking about formulas concerning acceleration, rate of fall, inertia, resistance, and such? First I want to know that you understand the basics, then I'll go beyond. You started talking about the fundamental forces of nature, so that right there indicated to me that you might not know as much about the subject as you might think you do.

terms are not adequate explinations. I assume you know how einstein proved the phenomenon of time dilation and length contraction merely with the fact that the speed of light is constant with respect to all frames, and a little geometry I want a proof like that.

And that was "obvious" to you?

Man, it took me a week to understand relativity! I still don't have it down pat.

You couldnt know what I want so dont try to pretend you do. If you cannot provide a proof then thats fine, I dont think I could without many hours of contemplation and much research.

I asked you specifically if you wanted the formula for a source wave. I can give that to you quite easily. I can't imagine what you intend to do with it, however.

If we are talking about wave motion towards a +x axis, then:

y= A sin (2 pi f t - (2 pi x)/W),

Where y=the displacement of the displaced particle (the molecules of air), A=the amplitude of the wave, f=the frequency, t=time, x=distance, and W=wavelength.

This is the formula used to mathematically describe a wave traveling through a medium. If you want the history and proof of it, ask your teacher, because all I got into this for was to comment on how inefficient acoustic levitation is. Being asked to provide proof of it in the explanation is somewhat akin to trying to explain to someone how a bike works, and having them demand I explain the laws of motion to them. Overkill, to say the least. If you don't understand how the formula works, well, you might have gotten in over your head, so ask someone who knows what level of education you are at to explain it to you. Personally, I'm still of the opinion that you are playing stump the judge, and I am somewhat tired of it.

[crystal sage]

hutchinson and acoustic levitation

http://youtube.com/watch?v=Qewy3UcrP84

and......

http://www.geocities.com/Athens/Olympus/6581/chronos15b.html

[donrobison]

hate to say this , but ai_guardian provided a link to a video of hutichson during one of his levitation experiments in which I saw a wire that looked to be supporting his "flying saucer". Lumping acoustic levitation with Hutchison only diminishes acoustic levitatiopns credibility to me.

[aquatus1]

Ahh, for the record, those clips aren't what I'm talking about.

[crystal sage]

Here's the site I remember reading about last year..... The tibetans had this sound technology...

http://www.crystalinks.com/levitationtibet.html

http://youtube.com/view_play_list?p=FFB5FCC7ED8449DC[/url]

Edited December 2, 2006 by crystal sage

[donrobison]

Thats an interesting account of tibetans doing some acoustic levitation. The explination at the end is baffling to me though.

[crystal sage]

Thats an interesting account of tibetans doing some acoustic levitation. The explination at the end is baffling to me though.

Which part???

This all reminds me of a couple of years ago when I bought 2 cheap tall CD racks...

Was working on the placement of these...put one on either side of the doorway...then got distracted...( the kids)... when someone ( me?) knocked a glass so that it rang... the sound of this was somehow picked up by the 2 CD racks like a tuning fork... and the sound rang on for several minutes.... it was amazing.... !!! I think the shape of the 2 racks and the distance of the glass was triangular....

The kids were hungry so I had to cook dinner and by the time later when I recalled the event the racks had been moved...( one into a daughter's room)...and I couldn't remember exactly where I stood when I knocked the glass....

You certainly could feel the energy...though...who knows if different notes would have had some interesting effects....or could levitate...or change something...somehow....

Edited December 2, 2006 by crystal sage

[shun]

I am dubious of any claims not backed by evidence, including levitation.

Special applications might involve either supersonic or ultrasonic conditions, or even those in between. Without being familiar with the experiment the OP referred to, I would just refer to the publications I have links for.

That said, waves generated and then reflected in the cup cavity move in two or more directions. Those that propagate outward become weaker by geometric effects and viscous damping. Those that propagate inward (A) amplify as outflows diverge. Those (A) dissipate by shocks as they approach the center ©. There, the separation between waves equals the minimum possible distance.

Under very special circumstances, the humidity may play a small factor. Consider at the wave compaction region ©, the possible emergence of sonoluminescence, for example. Though, certainly, only under certain highly controlled conditions.

Transmission of Sound Waves in Gases at Low Pressures

Link

Molecular Simulations of Sound Wave Propagation in Simple Gases

Link

The Limiting Kinetic Equation of the Consistent Boltzmann Algorithm for Dense Gases.

Link

Observations of Single-Pulse Sonoluminescence

Link

[donrobison]

"Waves generated by the cup". The cup must be a source of sound for it to levitate? I thought this could work with only an external source of sound.

[crystal sage]

http://www.livescience.com/technology/0611...levitation.html

Scientists have now levitated small live animals using sounds that are, well, uplifting.

In the past, researchers at Northwestern Polytechnical University in Xi'an, China, used ultrasound fields to successfully levitate globs of the heaviest solid and liquid—iridium and mercury, respectively. The aim of their work is to learn how to manufacture everything from pharmaceuticals to alloys without the aid of containers. At times compounds are too corrosive for containers to hold, or they react with containers in other undesirable ways.

Uplifting Experiences

Ladybugs

Beetle

Fish

Spider

Ant

Fish eggs hatch during levitation

"An interesting question is, 'What will happen if a living animal is put into the acoustic field?' Will it also be stably levitated?" researcher Wenjun Xie, a materials physicist at Northwestern Polytechnical University, told LiveScience.

Xie and his colleagues employed an ultrasound emitter and reflector that generated a sound pressure field between them. The emitter produced roughly 20-millimeter-wavelength sounds, meaning it could in theory levitate objects half that wavelength or less.

After the investigators got the ultrasound field going, they used tweezers to carefully place animals between the emitter and reflector. The scientists found they could float ants, beetles, spiders, ladybugs, bees, tadpoles and fish up to a little more than a third of an inch long in midair. When they levitated the fish and tadpole, the researchers added water to the ultrasound field every minute via syringe.

The levitated ant tried crawling in the air and struggled to escape by rapidly flexing its legs, although it generally failed because its feet find little purchase in the air. The ladybug tried flying away but also failed when the field was too strong to break away from.

"We must control the levitation force carefully, because they try to fly away," Xie said. "An interesting moment was when my colleagues and I had to catch escaping ladybugs."

The ant and ladybug appeared fine after 30 minutes of levitation, although the fish did not fare as well, due to the inadequate water supply, the scientists report.

"Our results may provide some methods or ideas for biology research," Xie said. "We have tried to hatch eggs of fish [during] acoustic levitation."

The research team reported their findings online Nov. 20 in the journal Applied Physics Letters.

[crystal sage]

http://www3.sympatico.ca/slavek.krepelka/ideas/stolev.htm

"The most important records and references come from Edward Leadskalnin, with his Coral Castle and his essays on magnetism and what had been left as his “estate” (see KeelyNet).

Norman Wootan with his magnetic resonance understanding and experimentation (see

KeelyNet), which helped me tremendously to “crack” the beast called sound.

Tibetian levitation report and report from middle east

http://keelynet.com/ufo/tibdisc######

http://www.sacred-texts.com/ufo/tibdisc.htm

http://images.google.com/images?sourceid=n...sa=N&tab=wi

There is actually a simpler way to indicate the harmonic frequency. You can place a small magnet on top of your stone and see when it begins to levitate. No polishing of the stone. But it might not be sufficient in finding out the best tunes and timber of the sound to use.

Set up a partial and stabilized geomagnetic field “gap” by building a ferromagnetic fence. It is not entirely necessary, but it will make the job easier and safer. This can be achieved by sticking two rows of mild steel poles into the ground. The higher they may be, the better. The poles must be closer to each other in each row, than across the isle, which will be your workplace. You should also hose the ground in the isle with water, or work on wet ground to start with, or at least ground the poles by a grounded wire. This will alleviate the problem with radio transmissions and other EM interferences creating a partial Faraday cage around your work. If you join the poles with a steel wire, you will have a better cage, but you will prevent yourself from being able to use the geomagnetic field for stone manipulation, i.e. pushing it wherever you want with magnetic field rather than your bare hands. Do not set your fence directly across geomagnetic meaning East-West. Set it approximately NS to start with your experimentation and find out how much you can deviate from it by experiment. Once your stone has levitated, it can be manipulated outside the fenced isle, but only so long as its resonance lasts in its synchronized mode. I am not certain if you can regenerate the sound and refresh the levitation without accidentally breaking the levitation down by poorly timed and synchronized acoustic wave. That has to be tried. "

Edited December 3, 2006 by crystal sage

[donrobison]

for the sound to do what I saw it do in the video, that is to lift the object one meter above the ground. it would have to have some work done on it. The energy of an object near the surface of the earth is defined to be mgh where g is 10 meters per second per second h is height and m is mass. The work energy theorem can be used here to find the work needed to do this

w=Ef-Ei

w=1kg*10m/s^2*1meter – 1kg*10m/s^2*0meters

w=1kg*10m/s^2*1meter

using si units

w=10j

power is work divided by time.

p=(work done)/(time interval)

lets say it took one second

p=10j/1sec

using si units

p=10w

it would take a ten watt speaker to lift a 1kg object one meter in one second.

All of the power from the speaker would have to be delivered to the object. from the energy stand point it is not impossible, but I've been to concerts where the speakers were probably in the hundreds of watts and nothing moved an inch anywhere in any direction. The sound only vibrated objects. It never manifested itself in a net force on a body. Although common speakers output enough power to lift an object of macroscope proportions, manipulating sound in such a way to produce a net force on a body is still inconcievable to me.