২ জুলাই, ২০১৯

Resonance.

I'm really speechless. from r/blackmagicfuckery


ADDED: I think you have to click through to get the sound... which is kind of the whole point. Don't know how to change that. Wouldn't have posted if I'd anticipated silence...

২৭টি মন্তব্য:

Fen বলেছেন...

Link not working? Please delete me after fix ;)

Ann Althouse বলেছেন...

The link works.

Just click the title ("I am speechless").

It's just that you have to click through to get the audio.

I copied the code for embedding. The embedding is just video without audio. That might be standard for Reddit. If it is, I won't be using Reddit for embedding in the future.

Fen বলেছেন...

okay my bad, I took your intro to mean "click on Resonance" instead of "Speechless"

MOAR coffee please.

rhhardin বলেছেন...

That's called a glass harmonica. Usually played on wine glasses filled with different amounts of water. If you have a thin glass, wet the rim and try it with your finger.

No doubt youtube must have a thousand instruction videos.

I did it as a kid.

Ann Althouse বলেছেন...

@Fen

K.

Just look at this for a while and all will be clear.

Ann Althouse বলেছেন...

@rh

Then maybe the visual is the better part of it.

Of course, I have seen those glasses (and even posted on the topic before).

But here you get the effect of the water becoming turbulent, just from the sound. Is that not different from all those glasses?

Known Unknown বলেছেন...

Great. Now I am in a crazy magic wormhole on this subreddit.

Jaq বলেছেন...

Maybe having studied physics sort of takes the romance out of it.

I knew a guy who spent his whole career looking for sympathetic resonances in jet engines. He was kind of boring, but he could probably jot down the equations to model this on a napkin at lunch.

Jaq বলেছেন...

“Black magic” Yeesh!

Fen বলেছেন...

Just look at this for a while and all will be clear.

And I was promised coffee. Bait n Switch witch! :)

rhhardin বলেছেন...

The water is spashing owing to vibration of the side of the bowl, not from the sound.

You probably get bessel functions. Look at the pattern of spash and google some bessel function images.

(I put away the new win10 scratch'n'dent laptop that I have to get out to play modern videos.)

rehajm বলেছেন...

Chladni patterns are cool. (second tweet down)

Jaq বলেছেন...

Did you see the second comment on rehajm’s link? “There is so much that we don’t understand.”

Oh my god. And this guy’s vote counts the same as anybody else’s. He probably thinks it should count for more.

Jaq বলেছেন...

He should have said “There is so much that I don’t understand.”

That’s a true statement for everybody.

MadisonMan বলেছেন...

I do like that the interference pattern looks square-ish to me. I wonder if it really is.

This is probably easily modeled. Someone has already written the PyThon code, I'm sure, it's just a matter of finding it.

Ann Althouse বলেছেন...

"Great. Now I am in a crazy magic wormhole on this subreddit."

Yeah, me too.

Ice Nine বলেছেন...

Didn't everyone do this with an ordinary drinking glass, as a kid? Or at least see it done in science class?

Freeman Hunt বলেছেন...

I got the audio without clicking through. In fact, it auto-played.

rhhardin বলেছেন...

The important part is that it's linear, which means it vibrates with a superposition of distinct patterns, each at a different (probably) frequency. If you arrange it so that exactly one of those patterns grows and the others decay, then you get a single frequency sounding. If the object has some symmetry, that vibration pattern most likely has symmetry too.

Clark বলেছেন...

That's a Tibetan singing bowl.

Fernandinande বলেছেন...

Who'da thunk that "Black Magic Fuckery" consists of jr high science demos?

That's called a glass harmonica.

Johnny Carson played that(those) while juggling a Buick on The Simpsons.

Howard বলেছেন...

Maybe the remembers this post

https://climateaudit.org/2009/02/24/steig-eigenvectors-and-chladni-patterns/

traditionalguy বলেছেন...

Is it Marianne Williamson at work? Debate prep her way.

Yancey Ward বলেছেন...

BlackMagicFuckery is one of the reddit threads I have bookmarked. Some pretty amazing stuff in there every day- some of it physics and chemistry applications, some of it pure illusion- some well done, some not.

Ken B বলেছেন...

Jeez. Bessel functions. Hardin is right, there probably are a bunch there. They won’t give you splashing sounds though. That might be caused by cavitation, or waves cresting against the side(?)

Ann Althouse বলেছেন...

"I got the audio without clicking through. In fact, it auto-played."

That's kind of worse...

Can't trust Reddit embeds...

Fernandinande বলেছেন...

Johnny Carson played that(those) while juggling a Buick on The Simpsons.

Close. Johnny sings opera while juggling a Buick then Hugh Hefner plays the glass harmonica.

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