PIRA Classification: 5A20.20
Description: Two small light spheres (ping pong balls coated with silver paint) are attached by strings to a dowel in such a way that the two balls hang down at the same height. A charged PVC or acrylic rod is used to charge the pith balls. The two will repel each other. The amount of charge transferred can be determined knowing the mass of the balls and the separation distance.
Special Instructions: Make sure you hear the build up of charge on the rod. This will be indicated by a crackling noise. Will not work well when humid (beginning of fall semester or summer session). It may take one or two tries to build up sufficient charge.
Condition: Good
Setup time: 1 minute
Safety Issues: None