Al Tobias (wat4y) - Office: Gibson S123 & Physics 218, (434) 924-0538
Demonstrations are cataloged according to PIRA Bibliography
PLEASE REQUEST DEMOS WELL IN ADVANCE
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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You have selected the following Demos:
Hacksaw Blade Resonance
Purpose:Demonstrates the concept of the natural or resonant frequency of a vibrating system. In particular, shows how the resonant frequency of a rod or ruler depends on its length.
Procedure:The drill has a bolt in its chuck which has been bent at a right angle causing the apparatus to vibrate when the drill is running. The drill is plugged into a VARIAC so that the speed at which the drill spins and hence the frequency of the vibration of the apparatus can be adjusted. The apparatus can be placed on a piece of foam or a student can be called upon to hold it. As the frequency of vibration is increased, the natural frequency of the longest blade will be reached first and it will begin to vibrate. The other two blades will remain still. Increase the frequency until all three resonances are found.
For a 140V VARIAC we find resonances at: