Part 2

 Conductors:  Materials where electrons flow freely.  Electrons are loose in atom  Examples - Metals (silver, copper, gold, aluminum, iron, steel, brass, bronze, mercury) and dirty water  Ex. Electric wires are usually made of copper (a good conductor)

 Insulators:  Materials where electrons do not flow freely.  Electrons are held tightly to the atom  Examples - glass, rubber, oil, asphalt, porcelain, ceramic, cotton, paper, wood, plastic, air  Ex. Electric wires have a plastic coating (a good insulator)

 Both insulators and conductors can be charged.  The difference is that  On an insulator charges are not able to move from place to place.  On a conductor, charges can freely move. If you try to place charge on a conductor, it will quickly spread over the entire conductor.

 Charging by conduction  Electrons transferred when one charged material touches another ▪ Charging with contact ▪ Both objects end up with same charge

 Charging by Friction  Electrons transferred when one material rubs against another  Objects end up with opposite charges  Example  Rubbing plastic rod with rabbit fur  Rubbing balloon on sweater or hair ▪ Because they are insulators only area rubbed is charged not the entire object

 You walk across the rug, reach for the doorknob and ZAP!!! You get a static shock.  Static electricity - accumulation of excess electric charge

 Charging by Induction  Electrons transferred when one material is near another  Charging without touching  Examples  Tape attracting pieces of paper

 Charged objects lose their charge when grounded.  become neutral

 Storm clouds generates static electricity  Areas of positive and negative charges build up  Charge builds & causes discharge between cloud/ground  Lightning = electric charges move through air, collide and emit light