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Al Tobias (wat4y) - Office: Gibson S123 & Physics 218, (434) 924-0538

Physics Demo Manual

Demonstrations are cataloged according to PIRA Bibliography


Due to Physics Building renovations, the lead time to set up demo requests has increased due to the need to transport equipment across campus. Please be kind and let me know well ahead of time what you need.

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 Harmonic Motion

 video  - Oscillator Beats


A simple method of showing the dependence of the beat frequency on the difference of frequencies emmited by two sound sources.


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  DEMO VIDEO DOWNLOAD w/ sound / 854x480 / 5.69Mb/s / 153MB size  

Connect a separate oscillator to each of the amplified speakers. Beats will be heard when one of the oscillators is tuned to a slightly different frequency than the other.
The beats can be visualized on the scope using the set up shown on the picture.


The very same set up can be used to explain why certain intervals are "musical" to our ears. The unison (1:1), an octave (2:1), the fifth (3:2) and the forth (4:3) all form periodic structures.


  • Audio Oscillator
  • Speakers w/ Built-In Audio Amps