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Homework Help: Why Sound Doesnt Travel Through A Vacuum

  1. May 9, 2005 #1
    Hey guys!
    I am just wondering if any of ya'll can help give me a good in depth understanding of "why sound waves can not travel through a vacuum".

    Also if any of ya'll know how to show a class presentation of how to demonstrate this and good instructions on how to make this object please let me know a.s.a.p.

    I would deeply appreciate it!

  2. jcsd
  3. May 9, 2005 #2


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    "Sound" refers to waves of compression which travel through matter. When there is no matter, there can be no such waves, and therefore no sound.

    - Warren
  4. May 10, 2005 #3
    The animation of the longitudinal wave on http://www.kettering.edu/~drussell/Demos/waves/wavemotion.html [Broken] is a good example of sound waves. If those were molecules of air they would continute bouncing like that until they hit your ear drum and then you would hear sound. Without those molecules or any others there could be no compression waves and no sound.
    Last edited by a moderator: May 2, 2017
  5. May 10, 2005 #4


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    You can demonstrate this of front of class by taking an alarm clock, a bell jar and a vacuum pump.
    Let the alarm clock ring and put the jar on top of it. As you pump away the air from the jar the sound will diminish until it is gone completely. When you let the air back in, you'll hear the sound again.

    Hopefully (probably) they'll have the necessary equipment at your school. Physics at school should always be accompanied by experiments.
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