Electric Charge & Static Electricity

Electric Charge The electric charge of an object is determined by the atoms that make up the object. a Physical Property … can be positive, negative, or neutral (no charge).

Law of Electric Charges “Like (same) charges repel (push away) and opposite charges attract (pull together).” Charged objects exert a force (either push or pull) on other charged objects.

The Electric Force definition : The force between charged objects The size of the force depends on two things: 1.Amount of charge: the greater the charge, the greater the force 2.Distance between the charges: the closer together the charges are, the greater the force

The Electric Field definition: An electric field is the region around a charged object in which an electric force is exerted on another charged object. All charged objects have an electric field around them. A charged object inside another object’s electric field is attracted or repelled by the electric force acting on it.

How do objects become charged? 3 ways objects become charged : 1.Friction: electrons are “wiped” from one object to another 2.Conduction: when electrons move from one object to another by direct contact 3.Induction: charges in an uncharged metal object are rearranged without direct contact with a charged object

Conservation of Charge When you charge an object, no charges are created or destroyed (“conserved”). The number of electrons and protons always stays the same, electrons just move to from one atom to another.

Detecting Charge You can use a device called an electroscope to see if something is charged.

Moving Charges Electric charges move through some materials more easily than others. Electrical conductors are materials in which charges can move easily. example : Metals Electrical insulators are materials in which charges cannot move easily. examples : Plastic, rubber, glass, wood, and air

Static Electricity Static means not moving. Static electricity is the electric charge at rest. The charges in static electricity are not moving away from the object that they are in, so the object will stay charged.

Electric Discharge Charges that build up as static electricity on an object eventually leave the object. The loss of static electricity as charges leave is called electric discharge. Sometimes static discharge happens slowly. – When this happens electric charges move into water molecules in the air. Sometimes static discharge happens quickly. – When this happens electric charges are transferred as a flash of light, a shock, or a crackling noise

Static Electricity Video