Electric Charge 22-1

All solids, liquids, and gases are made of tiny particles called atoms. Atoms are made of even smaller particles called protons, neutrons, and electrons. Electricity

Since most atoms have an equal number of electrons and protons, atoms are electrically neutral. Positive and Negative Charge

An atom becomes negatively charged when it gains extra electrons. If an atom loses electrons it becomes positively charged. Positive and Negative Charge A positively or negatively charged atom is called an ion.

If you have ever taken clinging clothes from a clothes dryer, you have seen what happens when electrons are transferred from one object to another. This imbalance of electric charge on an object is called a static charge. Electrons Move in Solids

In solids, static charge is due to the transfer of electrons between objects. Protons cannot be removed easily from the nucleus of an atom.

Sometimes, the movement of charge can be caused by the movement of ions instead of the movement of electrons. When table salt (NaCl) dissolves in water, the sodium ions and chloride ions break apart. Ions Move in Solutions These ions now are able to carry electric energy.

All charged objects exert an electric force on each other. The electric force between two charges can be attractive or repulsive. Electric Forces

Electric charges exert a force on each other at a distance through an electric field that exists around every electric charge. Electric Fields An electric field gets stronger as you get closer to a charge, just as the electric force between two charges becomes greater as the charges get closer together.

A material in which electrons cannot move easily from place to place is called an insulator. Examples of insulators are plastic, wood, glass, and rubber. Insulators and Conductors

Materials that are conductors contain electrons that can move more easily in the material. The electric wire is made from a conductor coated with an insulator such as plastic. Insulators and Conductors

Induced Charge This rapid movement of excess charge from one place to another is an electric discharge.

The process of providing a pathway to drain excess charge into Earth is called grounding. Grounding