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Concerning sound

  1. Oct 22, 2012 #1
    Why doesen't hand swaying produce sound and why does my slight scratching my skin produce an audible sound?
  2. jcsd
  3. Oct 22, 2012 #2


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    Staff: Mentor

    It does, it's just too low frequency/amplitude for you to hear it. Scratching is within the range of human hearing.
  4. Oct 22, 2012 #3
    It can, if you move your hand suddenly, and fast enough towards your ear, you can detect a dull "Thump", but it's so low in frequency that it's more of a gust of wind. In passing, you can actually hear a doppler shift if you generate a pure sine wave from a speaker and jerk your head towards it very hard.....or away from it.
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