How Does Acoustic Levitation Really Work?
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- เผยแพร่เมื่อ 2 ม.ค. 2025
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I talk about why it isn't intuitive how acoustic levitation works.
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That's the first time I finally understood what standing waves are, super good visual aid here, and very intuitive
same, i could never grasp them
Same
I have a machine based off this .. its a demo of the og tesla oscillator not the one people think it is its on my chan
I know right! I love this guy, he explains it so well that it makes it easier for dumb people like myself.
@@xxACIDVIRUSxx lol 👍
Awesome demonstration! Would have loved to see sand, or something granular to see the effects on it. Given the Node->Anti-Node relationship and the size of the material. Seeing the tinier material push closer to the Anti-Nodes than the objects you used would be neat.
My thoughts exactly. Perhaps some flour or other powder would work well.
I couldn't get any smaller particles to levitate. They have to be very small and very light (microgram range). I believe the smaller particle levitation is a lot more finicky and you have to get really good resonance. I'm not sure my setup could have achieved it.
@@TheActionLab Ah okay, work with what you've got right. Thanks for the response regardless.
@@TheActionLab what about something like smoke?
@@TheActionLab try cutting the Styrofoam with a needle, it should work :)
I've done experiments with arrays of these ultrasonic speakers at university. You can move little beads around in 3D space. If you put your finger in there you can actually feel the pressure zones pushing on the skin.
Thats awesome
That was the first thing I thought of doing if I had a setup like this.
Super understandable video.
It seems like this would have some practical applications in navigation as another means of a gyroscope. But then again why reinvent the wheel.
@@doiron12 not really. One possible application is as a volumetric display, if you move the particle around fast enough and make it reflect light. But there are better volumetric display technologies.
can it be scaled up to lift up a car? or can it be improved to act as a shield for cars during crashes?
Imagine doing all these experiments on your channel at the annual school science fair?
There'd be no competition!
Unless the competition also watches The Action Lab.
But if I did them I still wouldn't win I was truly hated during middle school even though I did everything right and stayed out of everyone's way,and still got bullied, they would say either I was cheating or I stole it from the entitled kids project.
@@cyankirkpatrick5194 :(
@@cyankirkpatrick5194 Buddy that victim attitude is going to get you absolutely nowhere.
bro this is legit what im doing for 2023 science fair
Now I really want to see what this would look like in a schlieren imaging system. With one of those you'd be able to see the standing wave itself.
It's been done! This whole video is basically quoting a paper from David Jackson in the American Journal of Physics (without giving any credit)
That slinky demonstration made me actually understand the standing wave! I learnt about it in Physics but never could properly visualise it until now. Thanks!
Loving this channel i learn so much from watching one video than an entire year in school 😂… also inspirational for ur creators 💯🔥
The best explanation I've seen of this. Thank you for the great teaching!
This channel is nothing short of phenomenal. Keep up the great work
What a great explanation and visual demonstration of a basic physics principle! Thanks so much.
This man has the unique ability to somehow insert the vacuum chamber in every video.
Damnnn, the standing wave in the slinky was actually so cool!!
What people don't understand is that destructive interferences don't cancel each other. The amplitude is the sound pressure and not energy. Cancelling each other means that the sum of forces is zero which create a node. The energy however is reflected by the node like it was a solid wall.
Your channel has just become my favorite! .....and you have been on the "tube" forever! Love these experiments!
Extremely helpful explanation! Truly gifted
I’ve been saying this for a long time, I think the solution to levitating cars (not flying cars) is sound!! Not giant fans (too windy), not magnets (need super conductors) but sound. It works at normal temperatures and pressure. Just install transponders under the roads and the car will have the receiver and voilà! Although, the question is can sound hold the weight of cars? But then again, most of the weight in cars is for energy to make the car move and balance on wheels - in this case there’s no need for all that, we’d have to reinvent the construction of cars!
Exciting stuff.
that would destroy your ears lolll
@@derricksallazzo1502 I don’t think it has to be lol. Could you very low or very high frequencies (ultrasound) that we can’t hear. Or use sound absorption.
@@amusableackeem The larger the object, the bigger the acoustic wavelength you'd need, hence the larger the "speaker". For a car, you'd need insane woofers whose wavelength would make it resonate with all kinds of objects. Also, these waves would affect the passengers, and it would transmit up as well, into birds and stuff. Not to mention the amount of energy required would be insane. I work with acoustic levitation of cells. You need 1 to 30 W to levitate micrometer sized cells. Imagine a car that weighs about 200 kg with passengers. I'd go with Musk's hyperloop instead :D
These are some of the best executed and reported experiments. There are a lot of youtube scientists but few show this level of experimental and analytical skill. Lots of love!
Wow. This made my head spin. Your videos are really good.
I'm so glad you hit this topic!!
I actually work in acoustic levitation or rather acoustophoresis, and it's even more complex than explained in the video. First of all, you don't need a standing wave to have acoustic levitation. You just need radiation pressure. So you just need high acoustic pressure, to have enough non linear effects that create that pressure. You can do that with standing waves but also with focused transducers. Moreover, the radiation pressure is much more complex than explained. You have particles that will go to the nodes, and particles that go to the anti node, regardless of their size. It depends on the acoustic contrast factor. For example, if we're talking levitating cells in water, you're gonna have blood cells that will go to the nodes, because their speed of sound and density is a bit larger than water, so the contrast factor is positive. If you have fat cells, which are less dense and with a lower speed of sound than water, they're gonna move to the anti-nodes. At its simplest, radiation pressure is a non linear effect that occurs when a powerful acoustic wave passes from a medium to another. The transfer of "momentum" from a medium to the other creates a force on that interface between the two media. Those media can be two liquids, like a cell in water, or an oil/water interface. It can also be liquid and solid, like a steel ball in water, or it can be gas and solid, like your experiment. I suggest you try water droplets in levitation, some fun stuff can happen, as well as powders, like ground coffee for example. You'll see strange patterns like spirals occurring, showing that on the horizontal plane the acoustic pressure depends on the horizontal coordinates as well, coz no standing wave is perfect. Also, there are amazing similarities between acoustic radiation pressure and electromagnetic radiation pressure. But when acoustic radiation pressure occurs due to a contrast of impedance (IE density and speed of sound), EM radiation pressure occurs due to a contrast of optical index. Also, photons have momentum, but technically an acoustic wave doesn't... So in the world of experts in acoustics, it is not totally understood how it works... You can extract radiation pressure from the equations but in my opinion there is no simple satisfying way to explain its source. A laser emits photons, those photons accelerate or decelerate when passing through an interface, so that interface is subject to a change in momentum, and a force is applied on it as a result. But with acoustic waves, where are the particles ? Where is the momentum ? Physicists have different views on this. Some will say it's simple and they're convinced it's this or that, but to be honest, it's just maths. There is no satisfying explanation.
Than you, your note has been very helpful. A possible answer to those last questions may be in a small sub quantum level where there are only waves of vibrations that intersect to create spikes of energy and small balls of energy that appear/disappear/appear on the larger quantum level. This would explain both the momentum and the two slit experiment observations.
Really cool!
I did know about standing waves since I have played with sound s a lot and have also been building a listening room (in which case, the task is to get rid of standing waves - which can be tricky sometimes, haha). At bass frequencies, the wavelengths get about the same as the room dimensions of normal rooms. Quite cool when playing with bass tone and a standing wave accors - certain frequencies can sound really strong at one point and just one or a few meters beside it, there is pretty much complete silence (since we only hear pressure, not air movement) - but these effects usually don't affect music or sound effects in a pleasant way.
I still had no idea that the pressure or air movements can counteract gravity like that - really cool.
Since particles go to the nodes or anti-nodes depending on their size, can this setup allow for separating particles by size? Thanks
I was wondering what would happen if you just tossed some salt or baking powder or such in there.
I also wondered about the potential of a "sound sieve"
Actually he got it wrong about the size of the particle. If particle go to anti node or node is determined by acoustic contrast factor, I.e. the material property of the target object.
I took that waves and optics a few years ago.
Only now, after this video, do I understand what the heck I was calculating in those acoustic problems
The way you push a particle to the next node reminds me of energy levels and quantum jumps in atoms.
And watching the slinky rings at the antinodes gives the ilusion they are teleporting but they are not.
Amazing video. The demonstration with the slinky is insane.
Can this be accomplished with light waves? I would love to see that!
I wouldn't think so, light waves wouldn't develop pressure like sound waves
Yes they are called optical tweezers, which utilizes focused laser beam
@@theolderwaitor3662 Very interesting!
@@thefuzzman Light waves have momentum which is similar. He's done a few videos about that. They can move objects in a vacuum
Would really love a dedicated video explaining how you built those speakers. Like calculations to arrive on the amplitude, frequency, based on what thing you want to levitate
school sucks beside explanations like this, thank you man
Love this channel. Are you a chemist or physicist by training?
Yeah he has a phd in chemical engineering. Dudes rly smart and has the knowledge to go with it
A good analogue to that is depth charges. If you look at the explosions, they seem to vibrate. And that's due to thermodynamics.
Could you put large particles and small ones at the same time ?
Like he’s literally the professor we all need!
What would you see if you puffed smoke into the “antigravity “ area?
That's a great idea! I wonder if it would look like a diffraction pattern?
Thanks. I finally understand how this works. You're right, other sites have a poor explanation.
New upload yay!
The visualizations are great in this video, very well explained, thank you!
I have one trivial question:
If air is the medium of this soundwaves in your experiment, what medium do electromagnetic waves use?
We all know this magnetic floater toys where you can levitate an object with electromagnets.
If the principle is the same (standing waves) what is the medium for electromagnetic waves?
Gravity?
@@godwinemerald2289 As far as my understanding goes gravity is not a thing, therefore it can be no medium like air or water, which are things.
Gravity is described as a force and a force is what something does and not what something is.
Electromagnet waves are a disturbance in the field lines of the electric fields all around us. So the electric field is kind of like the medium that is disturbed. Or another way of thinking about it it in terms of particle theory is that electromagnetic waves are actually photons that are shot out like bullets. A bullet doesn't need a medium to fly through, neither do photons.
IMO the issue in the video is that it seems like you need standing waves to have radiation pressure. You don't. You just need any wave, electromagnetic or acoustic. You also confuse a magnetic force with the electromagnetic radiation pressure, those are not the same forces at all. The first one results from the magnetic properties of materials, the other from the optical contrast between two media or objects. Radiation pressure can move any object, regardless of their magnetic properties.
@@TheActionLab Can you please inform me how can I get the system kit from India and how much is the cost?
Thanks
To any youngster who is watching this clip I implore you to take every advantage of whatever education you are currently receiving. I had to educate myself (as best I could) in adulthood. I wish I could give suitable emphasis on how a good education will enrich your life.
Military service provided me with options, and joining SF’s provided me with experiences that most people never have, regardless of their wealth or status, although I confess to a healthy kind of envy towards anyone who has received a classical education.
Ok sir❤🎉 im in class 11😊
What if, you play 2 notes with different frequency, say a C & a G ( a perfect 5th interval) , will the nodes & anti-nodes form at equal distance? What if other combinations, a C & a F# ?
If you use waves at two different frequencies from either side of the spring, you'll end up forming a beat frequency. When adding both waves together at a point, the amplitude, or size, of the resulting wave will have a pattern of decreasing and then increasing over the course of the beat frequency, which can be worked out by looking at the difference in frequency between the two waves used.
As the points of maximum and minimum amplitude of the wave won't necessarily be in the same place, I don't think you'll be able to produce a standing wave pattern that is stable enough to make objects levitate as in this video.
As always it was very interesting to see!
Can you help out Vladflix with some chemistry/physics? He posted a video about an effect where steam from a ball/dome of ice drops to the centre of a flaming cocktail and pools rather than just dropping indiscriminately.
It would be interesting to see how smoke would look in your apparatus.
Hello from the Beaver State.
This is so cool. Where did you get those things?
With the right camera you can see the sound vibrations in the air and using the right code you can take those packets of low and high pressure and change them to sound
I wonder if there is a particle size effected by both forces equally and settles between the node and antinode
I never watch videos that are longer than 3mins but this dude had a very interesting way to demonstrate things
Wonder if it's possible to suspend water droplets as well or if it would be too heavy but would be interesting to see if the droplets vibrate on the surface since their not rigid.
Is there any chance we could see this demonstrated in a liquid medium?
Don't think so, as liquids are almost uncompressible, as opposed to the air
Yes it does work in a liquid but it is a bit tricker, the wavelenght of the sound in liquids (water for instance) is much smaller so only very small particles can fit the nodes and also viscosity must be taken into account.
@@mariosebastiani3214 not true, look up acoustophoresis. I work in that field. You can levitate stuff quite easily. Yes it's less compressible, but it is compressible. Otherwise you wouldn't hear under water, have sonar, or whales communicating. But there is also much less dissipation than in air. Plus with focused transducers, you don't need standing waves.
@@nicolasbertin8552 That's interesting, especially your last sentence. Can you please point me at a specific online document on the topic? I'm used to work with air propagation only, and I'd like to broaden my knowledge. Thanks!
@@mariosebastiani3214 just look up any acoustophoresis article, they're all in liquids. For a full understanding of the subject, Lab on a Chip, the journal, published a series of articles called "acoustofluidics". You'll see in there how to produce levitation (mostly in liquids) with surface transducers, standing waves, or focused transducers. You just need sound to have levitation, that's why the video is misleading, it sounds like you absolutely need standing waves but you don't.
This guy always makes sense... Such a good teacher
Was really hanging out for that "...continue the experiment" promise!
Speaking about sound, if sound can't travel without air, can you record audio from inside (from a speaker inside and outside the chamber) the vacuum chamber?
It would be really loud for a bit while the air is sucked out and then it would get quieter and quieter untill there was no more sound. He could then do things like smack on the side of it and you would only hear it if it hits the chamber hard enough to vibrate the recording device itself.
It's crazy how deep you can dive into seemingly simple subjects.
I got a commercial for a show about this earlier. Great timing
I wish they showed us this slinky experiment in physics to explain longitudinal waves. The way that we did it is place a hook on a speaker facing upwards with a string connected going perpendicular to the sound wave out to a rod. Then we calculated the frequency we needed to play the speaker at to get the string to be in a standing transversal wave. It looked really cool, but didn’t really help us understand how the pressure waves of sound work.
So it means air molecules/particles are settling at the antinode?
What happens if you rotate the speakers 180° and really crank the juice?
Thanks for helping popularize these awesome little units! You're right. Way easier to deal with than the bulky flat-surface metal ones. I'm going to put them on the Physics Bus so kids can share in the fun!
I have seen this effect in ultrasonic bath sonicators. When we turn the bath sonicator on, the trapped air in the water makes small air bubbles that move to the nodes and thus cannot get out of the water. I can see the air bubbles literally stuck in the middle of the water.
Air bubbles in water actually have a negative acoustic contrast factor. So they move to the pressure anti nodes. If it were water droplets in air, they'd move to the nodes.
Best episode! This is it! That's how it works! Now imagine you understood how to control the sound waves to the point of being able to move all particles caught in the wave. This idea is the clue.
What a great demonstration and explanation!
The only thing missing is an affiliate link for those ultrasonic transducers !!!
I love this channel ... Love to learn new things in phy and chem love from India ❤️❤️👍🏻
Well i have done engineering in electronics and communication, but i didn't know this till now , well humbled by science and education and your knowledge. Lot of things to learn and especially relearn 🤣😌.
Very interesting! I wonder how it looks using smoke particles.
Can you make the soundwaves visible with like a powder or something else?
This was sooooo beautiful ❤️ thanks
Awesome. I love your videos. This is the best one yet
I bought the levitation kit that you put together to use with the arduino but never got it working. I would love to give this a try and your setup looks so simple, Could you please do a video on your set up like the ultrasonic transducers you used and what you used to send the signal to the transducers. That would be gratefully appreciated, David.
Wish I had you as a teacher in high school. You're extremely intelligent my feiend and you have a great qay of explaining things for the lay person.
What is the largest object you can levitate with this? Cool stuff!
Bigger transducers=bigger objects to levitate!
On a related note, there's a character in Xmen called Banshee with a super-powered scream. He uses this to fly by basically screaming at the ground and riding the reflected sound wave like a human surfboard. I've long wondered what the actual energy needed to do this would be, and what if any collateral damage there would be to anything in his path.
Is this possible large scale, like imagine a big speaker in your home that above it, it traps all dust particles? :P
That sounds cool and gross at the same time, a meter for how dirty your room is!
Really an outstanding and informative demonstration.
One of the best videos to be bestowed to mankind, thank you.
It would be really cool if you could charge them so that they repel each other and model electron orbitals
0:50 "...transducer is a little bit PARABOLIC so it can easily set up a standing wave even if you are not an exact multiple away from it." Please explain "parabolic"! If the transducer is in a self-resonant circuit, I would suspect that its frequency is detuned by the reflector.
Fantastic video my friend, great job and thank you.
What are you driving the transducer with? I want to make one and have a play!
I love this channel
Thanks a lot for this video and the clear explanation.. I've never seen this in my life until now..
I hereby crown you the new "Science Guy". Out with Bill Nye, In with The Action Lab Guy! Great stuff!
That was awesome, thanks my man!
1. Relativity of the electron and its motion. His waveform.
2. Refraction of different materials. Q: Why do metals not refract light?
3. Radius of an atom. The properties of substances depend on electrons.
4. The similarity between the gravitational field and the magnetic one. From what elementary law they are drawn. What unites them.
5. What is the frequency in a photon.
6. How light refraction works.
7. I believe electromagnetic radiation is due to the relativity of the electron, and the number of molecules.
8. How electr moves
Use argon gas in a balloon to focus the sound into one point like focusing light with glass
gas acts as focusing agent for sound 👌
He did a video on that once.
@@westonding8953 you are correct
I am soooo glad i subscribed and hit the bell...you are brilliant...great science for adults and children alike :-)
Can you use this effect to filter air?
I'm such a nerd for science. It's like porn addiction, but productive and fascinating at the same time.
I have to say, after watching the first video I seen of yours; then subscribing; and then getting notifications to a few of your recent videos. I'm very glad that I subscribed. . .
My favorite part of any science, is the lab portions where I can see it, and participate in it.
Your demonstrations are truly fun to watch every single time!
The last one I watched was with the laser and the small ball bearing. The light that actually passes through a spherical object at it's precise center. That was fascinating, and I can't wait to one day, replicate it for someone.
I didn't know acoustic levitation was a thing, but now I know WHY it is a thing.
I need this item in my life now!
7:52 “before we continue with this experiment, i’d like to thank the sponsor for this video”
**video ends one minute later**
Plz explain the working of MRI with law/principal or rule of physics
Could this effect be visualized with smoke and a high-framerate camera?
no coz smoke particles are very small. You'd need a higher frequency, more power, it'd take some doing. The larger the object, the higher the force. It's proportional to the cubeof the radius of the object. Meaning that a 1 mm particle will have 1000 times the force applied to it than a 100 µm particle. Smoke would be micron sized, so he'd need a billion times the power at least, although he'd gain power by increasing the frequency as well... But it'd take a lot. At least there'd be no gravity involved (or very little). But still, to attract those smoke particles from far out the nodes towards the nodes... Heh, would be tough.
An interesting demonstration.
I have had people who believe that a lost ancient civilisation tell me that this method might have been used to move dense objects like stone blocks, but this seems unlikely to me.
When you add in a Styrofoam chunk into the air gap, is there a relationship between the air pressure generated and the density / mass which can be lifted?
Is there a consequent down force on the acoustic generator when the styrofoam pieces are introduced?
With thanks, Simon
I love how you correctly described longitudunal wave but I think you labeled node and antinode wrong.
In standing wave node means no vibration and antinode means vibrating the most. It has nothing to do with pressure.
Could you please list sources for the US transducers, the frequency used, and the tone generator settings in case anyone wants to recreate this cool experiment.
I really love this demonstration and explanations....it would have made US Navy radar school quite a bit easier years ago
Have you shown the sand in a flat plate mounted to a speaker? Playing different frequencies on the speaker makes patterns on the sand
Look up “hair trick” car audio.
A few years ago when I was big into car audio, I could float towels, shirts, empty coke cans, and long hair Ofcourse in the window. It takes a lot of subwoofers and a lot of power. The larger the cabin space the more you need. I had 10-15’s on 20k watts.
You find the most incredible uses for your vacuum chamber 🤯
That's a nice concise explanation.
Okay, so now my question is: could this be scaled up the size necessary to function as, say a crane to levitate heavy objects? Could those two ultrasonic transducers be used as manipulators to maneuver parts into place?
Also, I have to wonder if it would even be worth substituting cranes for acoustic levitation, since actively generating acoustic waves would, I imagine, be more energy intensive.
Allegedly, sound was used to create the ancient pyramids, so I can't help but wonder if acoustic levitation could ever actually be adapted into a practical technology.
Oh, wow, I just built one of my own and I can do 5 :-). It is always amazing to watch this.
It would be cool to put a recorder inside the vacuum chamber while a sound is being reproduced to hear how the sound fades away with no air.