PURPOSE: To illustrate a complex resonance system.
DESCRIPTION: Four pendula have the same length, the largest 5000 g and the smallest 5 g. Tap the heaviest (top) weight gently. Energy couples downward through the pendula, with the amplitude of each successive pendulum becoming greater.
This demonstration is an analog to the system developed by University of Maryland Physics Professor J. P. Richard to increase the amplitude of the vibration from gravitational wave antennas. The mechanical vibration is then converted into an electrical signal using a transducer.
REFERENCES: (PIRA unavailable.)
EQUIPMENT: 2m square optical rail, table clamp, 1/2" diameter rod, 5g, 50g, 500g, and 5000g masses, eye for threading weights onto hanger.
SETUP TIME: 5 min.
Go back to Lecture-Demonstration Home Page.