What Does Acoustic Interference Look Like?

[@zakolia]

Shlieren effect and standing waves is a super fascinating mix. I would really enjoy playing with the possibilities.

[@shawnphillips4804]

Absolutely amazing!

[@Zeno2Day]

Excellent demonstration

[@choppps5858]

Looks like real magic. Totally impressive

[@bookdream]

This is fascinating and beautiful, I want to see more sound waves and fluid dynamics with this imaging technique.

[@backonrun626]

Wow this was very educative

[@davidnikon8501]

I love learning from you.

[@treyharper7885]

Wow, so fascinating! Thank you very much, you're an excellent teacher.

[@wolfgangrueckner7151]

thank you

[@MrEstebanEscudero]

Great video!

[@GlutesEnjoyer]

amazing demonstration. thank you!

[@patiram5439]

Nice project

[@hawkfpv1636]

Reminds me of the double slit experiment

[@cheyennealvis7899]

yup. follow that line of thought and you'll come to an amazing realization. But if you tell people they'll laugh at you. So it's better to just give them the bread crumbs they need to help them figure it out themselves.

[@ed-xs3pu]

That light is only a wave and the particle theory was to cover up the fact that they couldn't admit they were wrong?

[@ccc321321321]

Hello, professor, the video uses this method to see the movement behavior of waves in the air. Is there a way to see the movement behavior of the transducer?

[@NatSciDemos]

The transducer moves under the influence of a sinusoidal current, just like a transducer in, say, a stereo speaker. Because it's driven near resonance, the phase between the motion and input current will differ by about 90 degrees. Viewing the motion visually could be done using a very fast (approx 28 kHz) strobe light, but it would still be difficult to see because of the small amplitude.

[@nickplaysviola]

this is so good, thank you

[@AbeDillon]

If you offset the frequency of one of the transducers by 30-60 hz would the camera pick up the beat frequency?

[@NatSciDemos]

In principle it could be done, but as a practical matter it would be complicated by the fact that these particular transducers do not give a constant power output for all frequencies.

[@maitland1007]

Pretty nice mirror you have! Thanks for the video.

[@shaunlewia9710]

has a variation been tried with the double split experiment, to me it seems the wave forms are partictice when one transducer observes the other, and by the end we see everything is a wave. just time and case for observer for items to become solid. Blown my mind

[@wolfgangrueckner7151]

Unhappily, our mirror is not large enough to do a double slit type experiment.

[@ed-xs3pu]

The double slit experiment is the lightwave version of this. It has been falsely claimed to prove light is a particle, but we see quite obviously that it's just wave interference.

[@adrianskotniczny5413]

nice job

[@karlharvymarx2650]

The sound is ultrasonic, so by definition I can't hear it and even if I could, the audio is low pass filtered at about 15.5kHz. Yet I can hear something when the emitters are running. To verify that I'm not hallucinating, I downloaded the audio and had a look at the FFT. They really do seem to be producing extra sound, strongest at roughly 14.25kHz and 14.6kHz. I have noticed the same thing using cheap piezo buzzers to play with ultrasound at home. Is it caused by alternate vibration modes in the emitters, rattling, or something else? It is loudest at the et the end of the video.

[@wolfgangrueckner7151]

The transducers are known to also emit sub-harmonics

[@IronMoe]

this is very nice

[@funnycatvideos5490]

Light looks exactly like this when I leave my light on, through a slit in my bedroom door. Awesome that could definitely explain the double slit, just pressure mediations in the medium, nothing is being emitted lol.

[@zakolia]

Can you show gradually decreasing sound frequencies with corresponding strobe frequency? We could see the waves stretch appart.

[@wolfgangrueckner7151]

I'm afraid we can't do that with our transducer because it's a fixed frequency. Otherwise, it would be possible.

[@zakolia]

Ok, thanks for answering. I really like your videos

[@wolfgangrueckner7151]

@@zakolia thank you

[@zakolia]

@@wolfgangrueckner7151 I mean, we could tell if the sound waves are quantized. Streching them apart hertz by hertz and see if it jumps straight to the next position. I would love to play with your contraptions!

[@ScientificSolutions]

Very nice, thank you for sharing this new video! What I would like to know is, from one of your earlier videos in which you suspend balls on the standing waves, are you able to feel (with your finger, or a wand of sorts, etc) the compression zone boundaries?

[@wolfgangrueckner7151]

No, I don't feel a thing with my finger.

[@zakolia]

Wolfgang Rueckner hmm.. maybe you should see a medicine doctor!?

[@zakolia]

That's a question I had in mind for a long time, thanks.

[@wolfgangrueckner7151]

@@zakolia I believe most human body senses require a stimulus of the order of at least 1 millisecond long, or longer. 28 kHz has a period of 37 microseconds.

[@zakolia]

Wolfgang Rueckner wow! That's a great answer, thanks a lot. But I meant that as a joke: don't feel A thing with your finger... Thanks for your professionalism.

[@xxcood]

Hi there, it waz very interested to see some with a real knowledge about an idea that came to me since 10 years, and i wonder if you get with your knowledge to the results i did, but i couldn't deploy it because i was not my bath and also i didn't have the resources, you did mention about the levitation an opject with a sound wave, did you ever consider for levitation the source of the sound with those waves?

[@realamerican6161]

Wonderful experiments.. I would like to see the two emitting sources placed into one-another. Placed in such a manner that the position of the 2nd emitter may be adjusted spatially so the node/anti-node can coincide with the 1st. Much the same as you did with the glass plate. I enjoy the videos Wolfgang...

[@wolfgangrueckner7151]

Thank you. We'll try aiming them at each other some time in the near future.

[@WakarimasenKa]

The troughs interacting with each other would also be constuctive intereference, right?

[@wolfgangrueckner7151]

correct

[@WakarimasenKa]

@@wolfgangrueckner7151 thanks

[@il_vero_saspacifico6141]

Soooo cooolll

[@rogershanklin3210]

Why can we see the constructive interference, but not the actual, or whole(?), wave?

[@NatSciDemos]

To see the constructive interference, we use continuous illumination. We don't see the traveling waves under continuous illumination because they move very fast (the speed of sound is about 340 m/s).

[@tristang444]

Could you rotate the pair of transducers so we could see it three dimensionally?

[@wolfgangrueckner7151]

In principle, that could be done. In practice, that would be extremely difficult with our present set-up.

[@websonic1000]

HI, It would be great if you would oblige us to do experiment with double slit experiment with your setup.

[@wolfgangrueckner7151]

We need a larger mirror to do that ...

[@websonic1000]

@@wolfgangrueckner7151 Pitty, Have this feeling that Schlieren effect could show us what is happening with light beam before entering one of those two holes and after.

[@shamsulalamdhaka]

Nice. Thanks.

[@smokysmoka]

💙

[@axelvf1981]

Great video! I'm working on a project where we are looking for someone to visualize three different acoustic frequencies with schlieren photography. Would you be able to help us? We would of course be able to reimburse for your work.

[@wolfgangrueckner7151]

I would need to know more details (concerning what you want to do and see) to know if I can help you.

[@axelvf1981]

Of course! Can i send you an email?

[@wolfgangrueckner7151]

@@axelvf1981 Certainly. It's [e-mail]

[@johannesdeboeck]

This sounds very interesting. Did you manage to do this?

[@geoffrygifari4179]

i think its remarkable that transducers shoot up sound waves that go somewhat in a straight beam instead of diffracting outwards

[@wolfgangrueckner7151]

It's because the transducers a flat and not a point source. The waves do diverge because the flat areas are not all that large.

[@geoffrygifari4179]

@@wolfgangrueckner7151 for how long do you think the waves would not diverge? several meters?

[@wolfgangrueckner7151]

@@geoffrygifari4179 Generally speaking, waves diverge from their source by the ratio of their wavelength to the diameter of the source. In our case the wavelength is 12 mm and the transducer diameter is 45 mm. Thus, 12/45 = 0.27 radians, or about 15 degrees. And that's pretty much what we see in the video.

[@vladmatsala9753]

How does that mirror work? Is that some camera mode?

[@wolfgangrueckner7151]

It's a concave 2-m focal-length telescope mirror

[@mark5150ty]

Has anybody tried using infrasound with this setup?

[@kguy152000]

Wow

[@AbeDillon]

Why does ultrasonic sound travel so linearly?

[@NatSciDemos]

The waves are seen to spread out only a little bit in the picture because the transducers are flat surfaces and we're looking at a very close area around them. In other words, if the transducers were more like point sources then we would see the waves radiate out at a wider angle.

[@AbeDillon]

@@NatSciDemos That makes a lot of sense. I've heard that higher-frequency sounds travel more linearly than radially, but it makes much more sense for that to be a consequence of the transducer than an inherent property of high-frequency waves.

[@primodernious]

in theory you chould be able to levitate a small object with only two transducers in this configuration.

[@wolfgangrueckner7151]

correct ... and many people do it that way

[@MrJdcirbo]

You didn't talk about destructive interference, where crests meet troughs. That's part of the interference pattern. Otherwise, awesome video! I love how the strobe frequency created the illusion of a standing wave. Brilliant!

[@wolfgangrueckner7151]

thank you

[@deilusi]

rotate it 90' and add those tiny balls for extra effect.

[@labbeaj]

Looks like the clouds above our heads.... Especially, if the Nexrad Radars actually are manipulating the clouds instead of predicting them.

[@cheyennealvis7899]

he solved the problem relating to quantum mechanics and the double slit experiment and the nature of particle vs wave without even knowing it lol.

[@fattmouth7715]

Love it. Problem is the guy's voice puts me to sleep.

[@j3ckl3r]

I want to see what happens when you try to levitate a ball in it

[@SuperDatsun71]

Nikola tesla said this if I'm not mistaken already

[@patiram5439]

Easily found slowly bites 2.8 2.8 2.8 speed

[@vanotank1645]

даёшь такой опыт на 2 щелях

[@GPCTM]

1:45 really?! an Harvard man stating the obvious? omg it's "simply because" the light travels at different speed in that region "simply because" the density there is different "simply because" the pressure is different and because of that temperature is different and density affects light speed...

[@lalitpal9302]

The sound/vibration of AUM is very important in Hinduism. In yoga the there is whole science behind sound/vibration. The whole universe is menifested in vibration/sound which is AUM as per Hinduism. AUM is base of all sound just like red, green and blue is the primary color in the world of colors . I wish modern scientists can explore more into vibration/sound.

[@fvfdbsj]

after 3:33 this starts to giving me headaches this sound is so annoying

[@patiram5439]

Nies

[@tamaseduard5145]

Thank you sir 👍🙏 I remain to my idea that the formula of energy is this: ENERGY = ( ETHER / MATTER ) X ( RATE OF CHANGE )

[@GTAVBM]

This explains how ancient megaliths were moved around in the past.

[@tameraiead5212]

Looks fake but sounds true

[@nicolascovers.]

goofy ahh ohio physicist

[@chadcarvell1908]

Not at all like a double slit experiment.... Wink wink

[@wolfgangrueckner7151]

Correct. The waves radiate outward from the slits whereas these are planar waves.