I know that insulators do not conduct electricity because they do not allow the free movement of electrons. Let's assume the object that's going to touch the insulator is negatively charged. Does some charge get transferred to the the insulator or does no charge get transferred at all? I want to understand this more conceptually. I don't really get why insulators are used in electrostatic experiments.
[Physics] What happens when a charged (negative or positive) object touches an insulator
electricityelectrostatics
Best Answer
Actually, it is most likely that the charged object is an insulator.
Conductors are very hard to charge. Any charge you put on them disperses through the surface, so the charge density is pretty small and there is very little repulsion (and the field given off will be small). Touching a charged metal ball will not give that much of a static shock because there is no strong impetus for the charges to leave the ball.
On the other hand, on an insulator, the charges can only spread on a limited portion of the surface. This increases charge density greatly, and there is a lot of repulsion and thus stored energy. The electrons, being in a repulsive field (with high potential energy), will take a route off the insulator if provided. So charges on an insulator are more mobile when it comes to leaving the insulator, and thus we use insulators in electrostatic experiments. Metals "eat" charge and don't discharge as much, insulators "hold" them until they have a chance to discharge.