by Michel Maussion - University of Nantes - France
Rub a straw and then load the electroscope by induction. Next, when you draw near the same straw, the leaves begin by falling down.
Bring the straw nearer to the plate. The leaves then diverge.
See video (DivX Codec) 410 ko or 55 ko .
Load the electroscope by points.Bring the charged straw near : the leaves diverge still more.
See video (DivX Codec) 596 ko or 98 ko .