Two sorts of electric charges (b)

From the previous experiment one can infer that if the leaves part more when an
object comes closer, it bears charges of the same sort that the electroscope.

Inversely if the leaves come nearer, the charges are opposite.

A rod that electrify positively when rubbed will
induce a reaction opposite to that of the straw.

Electroscope charged positively


Electroscope positively loaded by induction with a negative straw.		By approaching the rod : the leaves part more.

If the leaves part more, you have found a positive object.

See video (DivX Codec) 318 ko or 56 ko .

Electroscope charged negatively


Negative electroscope loaded with a straw by contact or points.		By approaching the rod : the leaves join.

Bringing the positive rod nearer the

plate : the leaves separate.

See video (DivX Codec) 239 ko or 62 ko .

Electrostatics experiments