Cavendish Experiment: Apparatus Description (Home Experiment Main Apparatus Results Conclusions )


A laser beam is reflected off of a mirror, placed in the middle of the dumbbell, to a sensor. The sensor outputs a voltage that is recorded by a data aquisition program, written by my lab partner Alex Athanasopoulos.
After some manipulation, we get a graph like this:



From the changes in voltages over time we can tell the period. Also, the range of the voltages tell us the range of the movement. From the range of the movement, and the distance between the mirror and sensor, we can calculate the angular change between having the large masses next to the small masses or away from them, giving us our theta.

Updated 5/8/2002