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Can Atoms make a sound?

  1. Sep 29, 2007 #1
    I'm new here and don't know anything about Quantum Physics but I love the concepts and ideas that surround the theories.


    well I know it sounds silly but is it possible?

    Its something I was thinking about when talking about Absolute Zero, they have used so many methods to slow the atom down so I am just wondering if an atom made a sound could it be silenced as in sound cancellation, when two wave meet each other out of phase they cancel each other out.

    I am of course not talking about a sound or frequency our human ears could ever hear.
     
    Last edited: Sep 29, 2007
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  3. Sep 29, 2007 #2

    HallsofIvy

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    ?? The difficulty is that "sound waves", whether they are of a frequency we can hear or loud enough for us to hear, are still waves in the air or some other medium- which is itself made of atoms. You are talking, then, about atoms making other atoms move. In a sense, yes, of course. When you clap your hands together, it is the atoms and molecules in your hands that make the sound! But I don't think that is what you mean. With your reference to "slowing" atoms down to get to absolute zero you seem to be thinking that "canceling" the sound waves would "slow" the atoms. That is certainly wrong. However an atom makes a sound, the sound is NOT the atom itself!
     
  4. Sep 29, 2007 #3

    JesseM

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    Yes, take a look at the animation of a "longitudinal wave" on this page to get a sense of what the air molecules are doing when a sound wave passes through the air--sound waves are a collective behavior of very large numbers of molecules oscillating back and forth.
     
  5. Sep 29, 2007 #4
    I should not use the word sound but for lack of a better word or expression I had to use it, basically an Atom must have some rotation/ spin or clatter, I mean does some kind of friction not apply to Atoms?

    It must be wasting some energy somehow? I thought this is why even the deepest reaches of space are not at absolute zero because the atoms themselves lost some energy as they spun or just sat there.

    If you could magnify and increase the size of an atom in our real world, lets say to the size of a football, would it not be making some kind of noise even if we placed it in a vacuum?

    You see I used another bad word like noise but what I am trying to get at is could it be making a sound at the atomic level, wasted energy, it seems that everything makes some kind of sound at some level.
     
  6. Sep 29, 2007 #5
    i believe hari manoharan of stanford has done some work on the sounds of atoms. i think stm's are used to drag atoms across other atoms. here's a link: http://www.acfnewsource.org/science/atom_sounds.html
     
  7. Sep 29, 2007 #6

    A/4

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    Sort of related to your question is the phenomenon of "baryon acoustic oscillations". When the early universe was extreme hot, atoms, protons, and neutrons were sitting in a plasma "soup" of expanding matter. The different between gaseous pressure and gravitational attraction created what effectively/literally were sound waves in this plasma fluid. As the temperatures dropped enough to allow protons, neutrons, and eventually simple atoms to form out of the soup, the "snap" from the resistance to the outward expansion of the universe caused these shock waves to stall out, not unlike a damped ringing bell. Evidence of these acoustic oscillations is imprinted on the Cosmic Microwave Background and various other structures around us.

    For more information, see:

    http://t8web.lanl.gov/people/heitmann/darkuniverse/bao.html
    (A relatively non-technical and brief description)

    http://cmb.as.arizona.edu/~eisenste/acousticpeak/acoustic_physics.html
    (a bit more technical, but with some fun graphs and pictures)
     
  8. Sep 30, 2007 #7
    Fantastic web site. Thank you for the link.
     
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