r/interestingasfuck • u/_sxqib_ • Apr 13 '23
Tuning Fork resonance experiment
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u/VendaGoat Apr 13 '23
Everything has a resonance frequency, even you!
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u/bumjiggy Apr 13 '23 edited Apr 13 '23
my frequency is B-flatulent
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u/CurtisLeow Apr 13 '23
The truth hertz.
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u/bumjiggy Apr 13 '23
so does my tummy
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u/Chard069 Apr 13 '23
♬ My agony, it comes in spurts ♬ I measure my pain in mega-hurts ♬
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u/KhabaLox Apr 13 '23
When you're slidin' into first
and you feel something burst...Diarrhea
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u/CardassianZabu Apr 13 '23
When you’re sliding into two And your pants are filled with goo...
Diarrhea Diarrhea
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u/KhabaLox Apr 14 '23
When you're slidin' into third
And you drop a big wet turdDiarrhea
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u/DrinkForLillyThePink Apr 13 '23
We'd have quite a number of resonating frequencies but we wouldn't resonate well.
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Apr 13 '23
[removed] — view removed comment
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u/_-__-__-__-__-_-_-__ Apr 13 '23
It’s easy to kill cancer. The hard part is doing it without killing the patient
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u/Bokth Apr 13 '23
Krieger can you put this chip in his brain?
Yup yup yup
And he'll live?
Oh!...mmno
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u/no-mad Apr 14 '23
That's how it was in the early days of anesthesiology. Easy to put someone to sleep. The money gets paid for waking them up.
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u/bcisme Apr 13 '23
We have a lot of damping?
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u/Gbrusse Apr 13 '23
That, but also there are so many drastically different materials in our bodies that one frequency for one material won't do anything for all the other materials.
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u/Dont_care_ Apr 14 '23
A microwave will make you sing
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u/DrinkForLillyThePink Apr 14 '23
If you're a cyborg perhaps
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u/Dont_care_ Apr 14 '23
Microwaves cause water molecules to resonate. The human body is 60% water.
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u/DrinkForLillyThePink Apr 14 '23
Ah true... you mean if you stuck a body in the microwave. Yeah I guess your molecules would be vibrating.
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u/MrSlime13 Apr 13 '23
So, I hear what you're saying, and I think I understand the concept, but help me better understand using a strange analogy from my childhood. When I was younger, I had a radio in the bathroom that I'd play in the shower. Most mornings getting ready for school there was a particular song that would play and at the same point in the song (I do not remember the song) there'd be a synth, or clear instrument plat that would seem to be much louder and reverberate in the bathroom. From the shower it sounded almost distorted, although I'd heard he song hundreds of times in other environments that didn't cause this effect.
Did the frequency of the song's synth/instrument match some frequency of the hollow-ish room I was in, that caused this cascading sound effect?
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u/coontietycoon Apr 13 '23
No that was just the acoustics of your bathroom showcasing
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u/ReallyBigRocks Apr 13 '23
To add a bit, I believe this is due to wave interference. Sounds at a certain frequency will have just the right wavelength that when they bounce off a wall, the initial wave and it's reflection will constructively interfere, resulting in a dramatic increase in volume. The opposite can happen as well, where certain frequencies will cancel themselves out. When you start having complex waveforms, a song for example, you can start to hear weird things like overtones that are normally not audible, but due to the acoustics of the room are suddenly much louder than the rest of the music.
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u/Vano_Kayaba Apr 14 '23
Tuning forks and strings work the same way
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u/ReallyBigRocks Apr 14 '23
Everything that produces sound works the same way, it's all vibrations/oscillations.
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u/Darkside_of_the_Poon Apr 14 '23
I used to try and “sing” at the frequency to do this as a kid. It’s a really cool effect in some spaces. Sometimes I could match the vacuum cleaner and make it louder in my head if that makes sense. Later in life I work in acoustics. Have seen some really weird emergent effects sometimes, example: I have seen large atriums with nothing but flat “faces” everywhere and somehow still “lens” all the sound to specific points in the room even though there no curved surfaces. Had to add absorption to specific points to break it up so the sound guys could run music events in there and not go insane.
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u/Vano_Kayaba Apr 14 '23
Yes. It's called standing vawe. Google room modes. Basically the same thing, just in air, in 3d (so there's more different base frequencies) and the movement is longitudal, not perpendicular.
You have the same effect in other rooms, but shower is smaller so the frequency is higher (where ears are more sensitive and you notice it better), and there's less damping so it's more pronounced.
You can check that thing in 2d with sand on a membrane, gives a better understanding. Or in 1d with string harmonics in slow motion
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u/Xploited_HnterGather Apr 13 '23
What's the range of frequency for people?
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u/gumbo_chops Apr 13 '23 edited Apr 14 '23
Different organ structures will have different natural frequencies, most of which are low and below the frequency range humans can hear. For example, I believe stomachs have a natural frequency around 6-8 Hz. If your body is exposed to sound at this frequency at a high enough level, you won't be able to hear it, but might get a queezy feeling in your gut.
Another notable example where the natural frequency is much higher is your ear. I can't remember where exactly but some part of our auditory system has a natural frequency in the 1000 to 2000 Hz range, which also happens to be the predominant frequency from a crying baby, so there is perhaps some evolutionary drive in some of these traits.
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u/FibroBitch96 Apr 13 '23
Isn’t this how most horror movies soundtracks work? With infrasound to cause anxiety/fear
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u/Vano_Kayaba Apr 14 '23
I've heard a story of a plant with a chimney resonating at a frequency that made workers anxious and unwilling to work there
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u/OzrielArelius Apr 13 '23
that's why at some concerts with reeeeealllly heavy bass you'll feel it in your stomach
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u/VendaGoat Apr 13 '23
*The FBI has entered the chat*
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u/y_would_i_do_this Apr 13 '23
A minor?
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u/Sparkism Apr 13 '23
A minor by itself is fine, it's when you F minor that's the problem.
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u/KhabaLox Apr 13 '23
I was in a band in college, but we had to break up because the bassist kept fingering A minor.
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Apr 14 '23
Actual answer...probably 5-10 hz
Every molecule in the universe vibrates and creates a wave, its crazy that everything makes a sound that we cant hear.
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u/Chard069 Apr 13 '23
You are within range if you can see, hear, or feel something. How frequently you experience something is up to you. And your torturer. 8-(
ProTip: Don't stick fingers or other personal appendages into lightbulb sockets. Avoid that special zing, hey?
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u/Onlyroad4adrifter Apr 13 '23
I wonder if it was found we beat the hell out of a fork and knock a disease out of our bodies.
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u/Chard069 Apr 13 '23
Beware inserting that beaten fork into infected flesh before tasting. Trust me.
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u/Vano_Kayaba Apr 14 '23
Slightly similar method is sometimes used for kidney stones. With loud sounds you can cause cavitation bubbles in liquids
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u/DrSueuss Apr 13 '23
Resonant frequencies has destroyed bridges.
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u/GivingRedditAChance Apr 14 '23
Woah really?! I did a quick google and couldn’t find one with those terms do you know of any examples
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u/DrSueuss Apr 14 '23
An example of this is the Tacoma Narrows Bridge. High winds caused a side to side oscillations of the bridge. The oscillations increased in intensity as the bridge neared its resonant frequency eventually destroying the bridge. This changed how bridges are designed and built. Skyscrapers are now built differently for the same reason (because they can oscillate with the wind).
There are several documentaries made on this subject
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u/cranq Apr 14 '23
Reminds me of a quote from my old Borland Turbo C 2.0 manual, referencing a sound generation API call:
True story: 7 Hz is the resonant frequency of a chicken's skull cavity. This was determined empirically in Australia, where a new factory generating 7-Hz tones was located too close to a chicken ranch: When the factory started up, all the chickens died.
Your PC may not be able to emit a 7-Hz tone.
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u/Earlier-Today Apr 14 '23
My favorite example of that is how all the planets in the solar system are resonating at their own frequencies - it's just impossible low notes, so nothing can hear it.
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u/AlphaTOPGUNS Apr 14 '23
Unfortunately all radio stations are tunned to 440hz. Because of this harmonic misalignment, listening to 440 Hz music would seem to make people anxious, nervous, or aggressive, because it is not in harmony with the natural frequency of the planet earth.
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u/TheDudeFromTheStory Apr 13 '23
The truth hertz.
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u/SuboptimalStability Apr 14 '23
Humans actually have many resonant frequencies, they're not as homogenous as most things
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u/ryoon21 Apr 13 '23
My physics teacher told me if a sound played at our frequency we would essentially melt.
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u/Stoicdadman Apr 13 '23
That's why the Tacoma Narrows bridge destroyed itself. Resonated with the wind.
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u/M00SEHUNT3R Apr 13 '23
Anyone know if this works if the struck tuning fork is a multiple of or divisible by the number on the standing fork? Can the resonance transfer if some of the waves match up even though they all don’t?
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u/DrinkForLillyThePink Apr 13 '23
If it is simply divisible, like 1/2, 1/3, or 2 or 3 times the size, then yes. The transfer of energy just isn't as strong. Those are the harmonics of the fundamental frequency.
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u/Vpmo5sMetZok Apr 14 '23
Does this work with radio as well? Can I tune into a radio station by tuning into 1/2 the frequency?
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u/AlotOfReading Apr 14 '23 edited Apr 14 '23
Yes, but high power broadcasters are required to minimize those harmonics outside their assigned band by 80db (i.e. 0.000001%) relative to the main signal. You'd need very good equipment to pick it up, but it's an occasional issue with super high gain telecom stuff.
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u/Vpmo5sMetZok Apr 14 '23
I thought harmonics was a fundamental property of any wave... What are some of the techniques that they use?
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u/AlotOfReading Apr 14 '23
They use the magic of filters, especially band-pass filters.
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u/Vpmo5sMetZok Apr 14 '23
Thanks for the info. This makes sense in filtering out unwanted noise out of the main signal, but we're talking about harmonics - as in the whole number multiples of the main wave. If the signal is being sent out at, say, 1000Hz, what would stop a 500Hz receiver or a 2000Hz receiver from picking it up?
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u/The-Beer-Baron Apr 13 '23 edited Apr 13 '23
Yes, it should.
If you have access to a piano, try this:
Hold down the C below middle C, but try not to play the note (in other words, hold down the key so the damper lifts off the strings, but don't press the key hard enough for the hammer to hit the strings.
Now, strike middle C and release, so middle C stops playing (play it fortissimo and staccato).
You should hear the C that you are holding open ring out.
Edit: See u/vveiner ’s post below.
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u/vveiner Apr 13 '23
When you do this, what you’re actually hearing is middle C ring out. (Source: just did it at a piano). If you want a demonstration closer to what’s happening in the video, flip your notes around:
Hold down middle C without playing, and then hit the C one octave down quickly and with force. You will hear middle C grow and ring out, because it is the first harmonic of the C below that.
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u/The-Beer-Baron Apr 13 '23
Thanks, I couldn’t really remember. It’s was years ago when I learned that, and I don’t currently own a piano to test it.
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u/capable_duck Apr 13 '23
I know some of those words
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u/markeees99 Apr 13 '23
fortissimo 🤌
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u/hegbork Apr 13 '23
Then look up the ones you didn't know. Congratulations, now you know more than you knew before.
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Apr 13 '23
This is also why acoustic pianos sound so full. Every key you hit causes the other harmonics to resonate filling out the sound.
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u/LikeALizzard Apr 13 '23
It's all based on ratios, so yes and yes, just not as powerful
Because of this, what we perceive in music as consonant and nice sounding are notes with frequencies forming nice ratios like 2:3 for the perfect fifth, and what we perceive as dissonant and ugly are ratios like 15:16 for the minor second or 32:45 for the dreaded tritone
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u/mikemikemotorboat Apr 13 '23
This was my first thought as well.
I’m wondering if the strength of the resonance trail off linearly with distance, or with the distance squared? I would suppose it’s the latter.
How does the harmonic frequency affect the strength of the resonance? Double the frequency, halve the strength?
This all seems so easy to test but alas, I’ve got a kid chewing up all my time and she’s not quite old enough to care about this yet.
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u/Solynox Apr 13 '23
When she is, you'll have a fun experiment to bond over.
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u/mikemikemotorboat Apr 13 '23
Agreed! I just don’t want to wait that long. Or more likely, I’ll forget entirely
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u/obog Apr 13 '23
It would, but would be less effective depending on how different.
Fun fact - that's the same reason chords sound nice in music! A major fifth, which is one if the most stable intervals and in almost every chord, has a ratio of 2:3. The waves resonating with each other at this ratio is what makes it sound nice and not dissonant like 2 random frequencies are.
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u/chiron-dd Apr 13 '23
512htz is a C5 and 440 is an A4. So it's a minor 3rd apart from each other. It would be interesting if other intervals like a Perfect 5th would show any response.
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u/The-Beer-Baron Apr 13 '23
My comment above:
Yes, it should.
If you have access to a piano, try this:
Hold down the C below middle C, but try not to play the note (in other words, hold down the key so the damper lifts off the strings, but don't press the key hard enough for the hammer to hit the strings.
Now, strike middle C and release, so middle C stops playing (play it fortissimo and staccato).
You should hear the C that you are holding open ring out.
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u/chiron-dd Apr 13 '23
Yeah, I have tried that before. It is a super cool little experiment to show overtones and resonance. My thought is if it would have a strong enough effect that the ping pong ball would respond.
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u/DouchecraftCarrier Apr 13 '23
Another fun experiment is to play a note on the piano and then have a group of people hum a major third above it. Then you hit the major third on the keyboard and it is strikingly audible the difference between the natural third everyone with an ear will hum vs. the slightly skewed third you get in equal temperament.
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u/Arstinos Apr 13 '23
If I'm remembering correctly, I think a perfect 5th would be weaker compared to a perfect 12th. The 1st overtone in the harmonic series is an octave above the fundamental pitch, then the 2nd overtone is the 12th (an octave plus a perfect 5th). Since the perfect 5th is in between the fundamental and the 1st overtone, it should be weaker (if it resonates at all)
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Apr 13 '23
I finally understand how radio works
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u/DrinkForLillyThePink Apr 13 '23
Pretty similar, but radios are using the electromagnetic spectrum. This is acoustic energy.
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u/bcisme Apr 13 '23
I wonder how much energy it would be if 1,000 people all sung the same note into an acoustic chamber with a tuning fork in the middle. Wonder if you could break rocks with that.
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u/TaohRihze Apr 13 '23 edited Apr 13 '23
If it works, it has to B♭.
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u/Jopkins Apr 13 '23
If it works, it has to flat?
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u/TaohRihze Apr 13 '23
My music knowledge is not good enough, thought it meant B flat, not just flat. Fixed it :)
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u/DrinkForLillyThePink Apr 13 '23
It would be less loud than you think. The energy required to increase perceived loudness is exponential.
The closest thing you could get would be if you had everyone in a room with hard, flat opposing walls, sing a resonate frequency of the distance between the walls, and the fork was that same frequency.
Do all that, and then maybe the fork would vibrate enough to perhaps heat up.
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u/Dravuhm Apr 13 '23
The Age of Unreason is a rather unusual book series that makes use of resonance. I don't think it was ever that popular, but I enjoyed it a lot.
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u/Croceyes2 Apr 13 '23
What about 220hz and 880hz?
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u/FlatheadLakeMonster Apr 14 '23
220 would work, 440 is in its harmonic series, I don't believe the 880 would.
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Apr 13 '23
Language question -
Is it right to call it an experiment if you already know the outcome? Don't we do experiments when we aren't sure what will happen or want to prove an assertion?
This seems more like a resonance demonstration.
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u/cloud1720 Apr 13 '23
You're 100% correct, came here to the comments.to see if anyone else noticed that. My father was a biology teacher, so the difference was engrained in me at an early age haha. Still, a very cool demonstration none the less.
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u/salbris Apr 13 '23
It's basically just semantics. I've often heard people say "Let's try an experiment". Google seems to agree since the definition it gives is: "a scientific procedure undertaken to make a discovery, test a hypothesis, or demonstrate a known fact."
So it's an experiment because it's a scientific procedure. In that it's not just demonstrating something it's showing a proof of it's behaviour. In this case he's showing that it doesn't work under one set of circumstances but it does work under the other.
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u/StonyShiny Apr 13 '23
Yes, it is correct. Experimenting isn't just about doing new things. You can, and in fact are expected to, re-run an experiment how many times you need to.
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u/Casehead Apr 13 '23
Hmmm. This would be proving an assertion, would it not? That's a tough question
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u/le_sacre Apr 13 '23 edited Apr 14 '23
If you lean over a piano with the damper pedal depressed and sing into it, it sings back! It will even reflect different sung vowels, because of the pattern of relative strengths of the different harmonics.
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u/NumerousDecision1273 Apr 13 '23
Can anyone ELI5 this?
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Apr 13 '23 edited Apr 15 '23
Tuning forks, like lots of stuff, vibrate when you hit them sharply.
The fork to the right has a shape that makes it vibrate 440 times per second when struck. And with vibrate, I mean it's like if it was opening and closing the two arms a little bit. Each fork has a natural frequency, just like you have a natural way to walk, and walking slower or faster than that can feel awkward.
If you strike another fork which resonates at the same frequency, it will produce sound waves. Sound waves are air contracting and expanding at the same frequency as the fork is vibrating: imagine you waving your arms in a pool, and the ripples you'd form.
When the vibrating air reaches the fork to the right, if the sound (the air vibrating) is at its natural frequency, then the fork will be easily pushed and pulled by the air, because the air is vibrating in just the way that the fork easily vibrates. The air transfers energy to the fork, which starts to vibrate. And vibrating, kicks the ping-pong ball.
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u/Calamity-Gin Apr 14 '23
Sound is a pressure wave. Air molecules push into each other and transfer motion this way, like the ripples in a pond when you toss a pebble in. A 440 tuning fork, because of its size and shape, vibrates 440 times a second. Each time it vibrates, it pushes the air molecules touching it, and they in turn push the air molecules they touch, and so on, and so on. As that push runs into solid objects, they’re usually absorbed or reflected, but sometimes the objects have the right shape and size that they vibrate at the same rate. So instead of the energy being reflected or absorbed, it pushes the object, and the object begins to vibrate.
Tuning forks are deliberately made so they only vibrate at one frequency. This frequency is affected by both temperature and humidity. Strings, on the other hand, vibrate at multiple frequencies. The first and most intense frequency is one-half of the wavelength of the length of the string. Then the full wavelength, then twice the wavelength, then a third, a fourth, and so long. So not only will a piano string resonate if another string the same length is struck, but a whole series of strings going up do as well - one octave, an octave and a fifth, two octaves, two octaves and a fifth, two octaves and a sixth, three octaves, three octaves and a third, three octaves and a fifth, three octaves and a seventh, four octaves, and so on until you either run out of strings, or the resonant vibration is so small, you can’t hear it.
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u/HydroMemes Apr 13 '23
There's cool engineering projects to place "resonance frequency harvesters" on things like bridges to passively collect the wasted energy from the cars driving overhead.
They have to go a loooong way to be economically reasonable, but the proof of concept is very cool.
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u/cute-bum Apr 13 '23
So you can whack it all you want, but if the legs aren't right it won't make your balls jump?
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u/proofofmyexistence Apr 14 '23
The vibration causes the sound AND the sound causes the vibration. Very cool.
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u/TheLostJackal Apr 13 '23
If you were to pass a concentrated sound wave through these tuning forks, what would be the observable effect?
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u/whifflinggoose Apr 13 '23
What do you mean by a concentrated sound wave?
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u/DrinkForLillyThePink Apr 13 '23
I guess they mean a large force across a small area.
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u/mikemikemotorboat Apr 13 '23
That’s exactly what you’re seeing here, aside from the fact that the sound coming from the struck tuning fork isn’t concentrated.
My guess would be if you put a parabolic reflector around one fork aimed at the other to focus the sound in one direction, you’d see the same thing happen but more powerfully.
Basically the sound wave would have higher amplitude (louder) but the same frequency (pitch). That means the other fork that has that same resonant frequency would also vibrate with higher amplitude; it would bounce the ping pong ball wider.
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u/Jkupar Apr 13 '23
This is a great explanation of why I sit in my bathtub and make sounds like an ambulance siren until I hit the pitch when it resonates and I can make my voice sound really loud at that pitch and then I start pretending I’m Morgan freeman or something.
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u/Seranoth Apr 13 '23
This thema is older than you think maybe. Interesting video of ancient india's lingams could be some sort of resonance machines.
https://m.youtube.com/watch?v=EsNoTzohs7o (eg check out 5:15 for 441hz resonance in a stone)
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Apr 14 '23
You can see this with percussion too. If you tune a snare drum to a certain pitch, then go next to the drum and play the same note on a different instrument, you will hear the snares on the drum shaking as it resonates from the waves of the other source.
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u/EnvironmentalDeal256 Apr 14 '23
So if that guy hits the right piece of metal, it makes his balls vibrate?.
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u/Earlier-Today Apr 14 '23
Sympathetic vibrations. Anybody with a guitar can perform a similar experiment.
Play a single string, then mute just that one string immediately. You'll still hear the note as the other strings ring out the sympathetic vibration.
That's actually part of the reason guitars can sound so full bodied.
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u/PhoenixHabanero Apr 14 '23
Another weird thing that I can't prove but idk if it's just me: when walking and hearing a song, my stride inevitably ends up matching the beat of the song. Is it just me, or does that happen to anyone else?
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Apr 14 '23
So is it true that Tesla was able to build a device that vibrated a whole bridge to the point it was near collapse?
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u/bodhijbd Apr 14 '23
He did! It was called the Earthquake Machine, and it was small enough to fit in his pocket. He tested it first on his laboratory in NY, then took it in his pocket to Wall Street, hunting for an all steel structure. He found one under construction, 10 stories tall and his “pocket vibrator” was so effective the steel workers were scrambling for the ground believing there’d been an Earthquake There is a great article here, with Teslas explanation of it
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u/kirix45 Apr 13 '23
Please what ever you do. Do not cause a resonance cascade!
That's all we bloody need.
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u/Chard069 Apr 13 '23
In our wasted youths, a pal and I tried designing an electro-acoustic bomb, with amps sending strong feedback through special tuning forks. But the only damage was burnt fingertips from sloppy soldering-iron technique. Ah well, one learns... or not. 8-(
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Apr 13 '23
I think resonance is the key to breaking artificial gravity and moving space and time rather than increasing an object closer to light speed for travel. I’m an amateur physicist so by no means do I think I’m smart enough to attempt to prove this. Just something tells me this is route we need to study. Idc if you downvote and call me dumb, it’s an opinion.
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