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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  - Pendula, Spring and Simple
 Pendula, Conical and Torsional
  video  - Pendula, Physical (Center of Percussion)
 Projected Uniform Circular Motion
 Damped Mass on Spring
  video  - Forced Oscillations
 Hacksaw Blade Resonance
  video  - Resonance Wire Ring
  video  - Inverted Pendulum - Function Generator
 Inverted Pendulum - Reciprocating Saw
 Coupled Pendulum Oscillators
 Coupled Magnetic Oscillations
 Coupled Harmonic Oscillators
 Lissajous Figures on the Scope
 Lissajous Fifures with Laser
 Parametric Amplifier / Oscillator

 video  - Forced Oscillations


To show resonance in a damped oscillatory system and to demonstrate destruction of an undamped (no resistance) system.


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  DEMO VIDEO DOWNLOAD / no audio / 1920x1080 / 24.19Mb/s / 432MB size  

  DEMO VIDEO DOWNLOAD / no audio / 854x480 / 5.69Mb/s / 99MB size  

Set up demo as shown making sure that the mass is aligned properly in the tube. Start motor and run speed up and down pointing out the effects of too little and too much speed. Reach resonance and let go for a few cycles to establish regularity and watch as the system 'destroys' itself. Now is a good time to show the Tacoma Narrows movie.


With motor speed range set to "HI", the apparatus can be shown the following (numbers represent dial settings):

  • Underdriven - 85
  • Overdriven - 100
  • Resonance - 92

One can show the system "go thru resonance" without destroying itself in the undamped system by going quickly to 100 on the dial to the "overdriven" case.


  • Bodine Variable Speed Motor and Control Box
  • Forced Oscillation Apparatus