Need More Proof?
Give These a Try

1.

Adjust a water faucet until you get a very thin stream. Now charge up your trusty comb one last time, bring it near the stream, and observe.

2.

Tear some paper into very small pieces. Lay them on a table and bring your charged comb near them. What happens?

Are you seeing a pattern here? So far you’ve tested four different neutral objects: pepper, foil, water, and paper. Yet every time you brought your charged comb near them, the same thing happened. The neutral object was attracted to the charged object.

You’re now an expert on the rules for static electricity, so this next question should be easy: Do these neutral objects 4 behave like they have the same or opposite charge as your comb?

a

By the way, this process has a special name. It’s called induction. Based on your experiences, would you agree that induction causes a neutral object to be attracted to a charged object brought near it?

Like the neutral foil ball that was attracted to the charged comb, we saw neutral pepper particles attracted to the charged portion of the plastic lid. Describe what the electrons must do for this to happen.

b

OK, OK So What?

By now you must be wondering, is static electricity good for anything practical?

Well, refer back to the experiment on page 12. If we substitute negatively charged black powder for the pepper and, instead of the plastic lid, have a specially coated surface that loses its charge when bright light strikes it, we now have the basic idea of how a photocopy machine works.