ELECTRICAL EFFECTS result from an imbalance of electric charge. There are two types of electric charge, named positive (carried by protons) and negative (carried by electrons). If charges are opposite (unlike), they attract one another, while like charges repel. Forces of attraction and repulsion (electrostatic forces) exist between any two charged particles. Matter is normally uncharged, but if
electrons are gained, an object will gain an overall negative charge; if they are removed, it becomes positive. Objects with an overall negative or positive charge are said to have an imbalance of charge, and exert the same forces as individual negative and positive charges. On this larger scale, the forces will always act to regain the balance of charge. This causes static electricity. Lightning, for example, is produced by clouds discharging a huge excess of negative electrons. If charges are “free”—in a wire or material that allows electrons to pass through it—the forces cause a flow of charge called an electric current. Some substances exhibit the strange phenomenon of magnetism—which also produces attractive and repulsive forces. Magnetic substances consist of small regions called domains. Normally unmagnetized, they can be magnetized by being placed in a magnetic field.Magnetism and electricity are inextricably linked, a fact put to use in motors and generators.
