Electric Charge 6.1.1

Atomic Model

Matter is composed of atoms. These atoms are composed of: Protons - positive charge Neutrons - no charge Electrons - negative charge

Atoms do not have a charge because the number of electrons and protons cancel each other out. Ex. 3 protons (+) and 3 electrons (-) = 0

Charged Objects How do objects get charged? They either gain or lose electrons. 3 protons (+) and 5 electrons (-) = 7 protons (+) and 2 electrons (-) =

Positive and negative charges exert forces on each other Opposite charges attract Like charges repel

Positive and Negative Charges

How Can You Charge Objects? There are 3 ways objects can be charged: Friction Conduction Induction In each of these, only the electrons move.

Charging by Friction occurs when electrons are “wiped” from one object onto another.

Static Electricity Static electricity is the accumulation of electric charges at rest on an object. The charges of static electricity do not move away from the object that they are in. So, the object keeps its charge. Ex. Clothes taken out of a dryer

Electric Discharge the loss of static electricity as charges move off an object Sometimes, electric discharge happens slowly. Ex: static on clothes Sometimes, electric discharge happens quickly. Ex. wearing rubber-soled shoes on carpet, lightning

Law of Conservation of Charge Electric charges can be transferred from object to object, but it cannot be created or destroyed.