Charges and How They Behave

The Atom Atom : the smallest unit of an element Made up of smaller subatomic particles: protons, neutrons, and electrons

The Atom

Charges Positive charge – there are more protons than electrons Negative Charge – there are more electrons than protons Neutral Charge – there are the same number of electrons and protons

The Law of Electric Charge: Opposites Attract!! The Law of Electric Charge: Opposite charges attract each other Like charges (the same) repel each other

Friction (caused by rubbing two objects together) A: before rubbing a balloon on hair, both have a neutral charge or the same number of electrons and protons B: when the balloon is rubbed on the hair, negative charges are transferred from the hair to the balloon. The hair now has more protons or positive charges and the balloon has more electrons or negative charges .

Conductors and Insulators Conductor cue card Insulator cue card A material in which electrical charges can move easily Examples: copper, iron, salt water, Earth A material in which electrical charges cannot move easily Examples: wood, paper, oil, plastic, pure water Electrical cords of most appliances and electrical tools are made of a conductor that is covered by and insulator