Info

A long string is stretched across the full length of the front table; at one end it goes over a pulley to a mass hanging over the edge, at the other end it is driven by a mechanical oscillator. Vary the frequency of the oscillator using a function generator to show standing waves of different harmonics. The tension in the string can also be changed by adjusting the mass at the end of the string.

PLEASE BE CAREFUL when adjusting the amplitude (depending on the function generator, you may need to set it to zero when changing frequency ranges), as it's VERY EASY to burn out the expensive speaker.

Setup Instructions

1. The string should be attached to the stand, fed through the opening in the mechanical vibrator, and extended along the table to the pulley. Usually about 200g is a good weight to hang on the string.

2. The function generator output should be connected to channel 1 of the amplifier and the amp output should be connected to the mechanical vibrator. The volume on the amplifier should be quite low such that the mechanical vibrator doesn't vibrate too violently and a fuse doesn't blow.

Parts List

Mechanical Vibrator in C. Oscillations and Waves, 1C

Elastic String in C. Oscillations and Waves, 1C

Pulley C. Oscillations and Waves, 1C

Weight Set in A. Mechanics, 1B

Function Generator in L. Misc

Amplifier in L. Misc

Relevant Simulation

Demo Example:

Other Information

Standing Waves Movie
Normal Modes of a Bar at Resonance

Real-Life Examples

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More Advanced Reading

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