Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Question about light and sound.

  1. Jul 25, 2008 #1
    Just to let everyone know - I'm a Senior in highschool. I know a little bit about science and physics - but I am no where near a genius in the subject... so if I say something totally stupid - laugh, but be sure to correctly me kindly. Heheheh...

    Aight, so here's the question.

    I'm doing research on the history of music, right? And I think, what if light can make music? It kind of make sense... Light is a wave that when it strikes an object - it causes a vibration - which makes sound - right? And music is sound that has rhythm. So is it possible that light can make music? (Whether or not human ears can detect it)

    If you have any interesting info on this - or reasons that that doesn't work out... could you let me know? Any better explanations would be great. I'm writing a research paper on it and need it a.s.a.p.


    Lady L'Rae :blushing:
  2. jcsd
  3. Jul 25, 2008 #2
    Are you asking in theory or practice?

    One way is to frequency shift a light beam, but visible light spans a fairly narrow range of frequencies, less than an octave. Or you can superheterodyne a light beam against a yellow reference. I suspect that would be difficult and expensive to build.

    Another way would be to code the sound into a modulated light beam, shine it onto a photocell, and amplify the resulting current and drive an amplifier. Say you wanted to play the sound of, say, the view of a mountain landscape. Take a small spotting telescope, and put a prism at the eyepiece. Make five or six photocell amplifiers tuned to different frequencies, and use that signal to drive either the pitch or volume of a tone generator. Sweep the telescope over the scene, and listen to the chords change. I wonder if that could sound musical with the right kind of scene, and the right way to sweep the scope.

    But does light make any sounds without such a device? No, not really, and certainly not directly. The frequencies are too high and the energies per photon are too low. Air molecules don't react to that much, which is why air is transparent. Indirectly, on large scales, the light of the sun does heat the earth, more at the equator and less at the poles. That makes for wind and weather. So I guess you could say that the sound of light is the howl of the wind and the crash of thunder.

    Is that like what you were thinking of?
  4. Jul 25, 2008 #3
    Optics fibres can conduct signals, including sounds/ musics
  5. Jul 25, 2008 #4
    Thank you so much!

    I'm interested in the idea of the sun causing the wind and thunder...

    And I was speaking in theory - are there any theories on this at all... I meant naturally - without a device - there really isn't anything on a small scale?

    Thanks for your response!
  6. Jul 25, 2008 #5
    Ooh, ooh... further explanation?
  7. Jul 25, 2008 #6


    User Avatar
    Gold Member

    And apparently, once you eliminate the noise from known sources, you can hear that the Earth actually rings like a bell. A very, very large bell.
  8. Jul 25, 2008 #7
    Really? How? This is cool...
  9. Jul 26, 2008 #8


    User Avatar
    Gold Member

  10. Jul 30, 2008 #9
    here's something to think on;

    Light is really nothing more than a range of electromagnetic wave frequencies that our biological optic nerves can detect. If we then decide that electromagnetic waves of all frequencies were a form of light.. or rather, if we throw out the notion of light itself and focus only on the ambient EMF signals around us as a source of music, here is what you can do...

    Sound that the human ear can detect is in a range roughly from 20hz to 30,000hz, if we then listen for EMF at those frequencies (we could not 'see' those frequencies of radio wave) with a coil designed to amplify those signals and pass them through a speaker, what you will get is audible sound generated directly from natural or synthetic EMF.

    Some folks have done just that with celestial bodies.. Like Jupiter for example (check youtube for 'the sounds of jupiter' for an example).
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook