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Topic: Listen! Can you see it? (Read 1232 times) |
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rloginunix
Uberpuzzler
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Listen! Can you see it?
« on: Oct 16th, 2014, 6:58pm » |
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Listen! Can you see it?
That is it - how can you make sound visible?
This question (and the intended answer) is based on a real scientific event and has to do both with math and physics, which go hand in hand on this one, in tune so to speak.
P.S.
I have no doubt in the awesome inventive powers of the members of this forum so other scientifically plausible answers are also welcome.
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diva
Newbie
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Re: Listen! Can you see it?
« Reply #1 on: Oct 16th, 2014, 9:37pm » |
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it would be great if i cna understand more about it. @william pen
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SWF
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Re: Listen! Can you see it?
« Reply #2 on: Oct 16th, 2014, 10:16pm » |
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Density difference in air results in different index of refraction, which can be visible: see slow motion video of power explosions, or shadow graphs of high speed projectiles. Can sprlkle sand on a drum head to see vibration patterns. See "sonoluminescence": light emitted from bubbles in an ultrasonically excited liquid.
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dudiobugtron
Uberpuzzler
Posts: 735
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Re: Listen! Can you see it?
« Reply #3 on: Oct 16th, 2014, 11:46pm » |
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Buy one of these?
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towr
wu::riddles Moderator
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Some people are average, some are just mean.
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Re: Listen! Can you see it?
« Reply #4 on: Oct 17th, 2014, 1:54am » |
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A balloon (or other receptive surface) and a strobe light?
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Wikipedia, Google, Mathworld, Integer sequence DB
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alien2
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Re: Listen! Can you see it?
« Reply #5 on: Oct 17th, 2014, 4:36am » |
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on Oct 16th, 2014, 6:58pm, rloginunix wrote:| That is it - how can you make sound visible? |
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Nobody suggested, except for crazy people, that the written word 'sound' is invisible. My imagination has its limits so this is all I can think of.
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rloginunix
Uberpuzzler
Posts: 1029
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Re: Listen! Can you see it?
« Reply #6 on: Oct 17th, 2014, 9:08am » |
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All the ideas are interesting but SWF and towr got closest to the intended answer. Out of the three main items used in the experiment they both mentioned one.
For a clue as to the second item look at the problem statement, there's a hint there.
The third item is so common that most of us see it every morning without giving it a second thought.
The last hint: time travel to 1855.
[edit]
Sorry. One more thing. Don't forget about the math portion - least common multiple, rational and irrational numbers are involved.
[/edit]
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| « Last Edit: Oct 17th, 2014, 9:14am by rloginunix » |
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rloginunix
Uberpuzzler
Posts: 1029
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Re: Listen! Can you see it?
« Reply #8 on: Oct 18th, 2014, 8:26am » |
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That is an interesting new development. Thank you for the link, alien2. I've bookmarked the page.
May be my clues were too vague, sorry.
So SWF and towr got the beam of light.
The second item is hinted at in the problem statement's "... in tune so to speak". If you play(ed) a guitar, for example, you likely have used this item once in a while.
When you look into the third item in the morning someone very familiar stares back at you.
1855, France.
Wiki has an article about it, another article covers the experiment's math, youtube has a bunch of clips showing the recreation of the experiment.
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rloginunix
Uberpuzzler
Posts: 1029
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Re: Listen! Can you see it?
« Reply #9 on: Nov 7th, 2014, 11:42am » |
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Just me. Tying up the loose ends.
The experiment I was hinting at was performed by the French mathematician Jules Lissajous where he used two tuning forks in orthogonal formation. Each fork had a small mirror attached to it. When a beam of light is shone on the vibrating mirrors it paints a curve on a wall thus making the sound visible.
If each vibration is a simple harmonic motion then the resulting compound curve traced by an (x, y) point is:
x = aSin(  t +  )
y = bSin( t + )
If the ratio (\) is a rational number then the resulting curve (no matter how intricate) will eventually close and the motion of the above point will be periodic, the least common multiple of the two individual periods being a common period.
If the above ratio is an irrational number then the curve will never close but the point will eventually paint the a by b rectangle.
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