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Resonance frequency of an object

  1. Feb 4, 2005 #1
    hi this is not physics homework
    I really need to find out the natural frequency of a window size glass so that I can brake it with a couple of speakers. this is not a prank joke either. I need a practical way to find it help please. So far all i know is that the frequency is low by hitting it with a stick and I have a tool to generate a sound of any given frequency. What do I need to do now?
  2. jcsd
  3. Feb 4, 2005 #2
    Find out the material of the glass window (I believe some are SiO2 silicon dioxide). Then find out at what frequency SiO2 vibrates at a given temperature.
  4. Feb 5, 2005 #3
    If you get a frequency generator and a small speaker (approx 5 cm) and put the speaker face down on the glass(not in a case, just straight against it), change the frequency of the small speaker until it starts jumping and buzzing around on the glass the most. This will be your resonant frequency, when the power of the little speaker gives the most oscillations in the glass.
  5. Feb 5, 2005 #4


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    If you have a 'tuner' (a device to measure pitch), then you can give the glass a clunk with a spoon or so and record the frequency of the *ping*. That'll be the resonant frequency.

    Another way is to strobe the glass with a stroboscope while going at it with the speakers.
  6. Feb 5, 2005 #5
    I'd knock on the window, and record the dissipating noise with a microphone hooked up to a 'scope.
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