Electric Current
Electricity is the flow of electrons through a conductor. Metals such as copper, silver, and iron are good conductors of electricity—that is, they allow electrons to flow through them with relative ease. Other materials, like mica, paper, and some plastics, are insulators—normally, electricity cannot flow through them because of their high resistance to electron flow. So these materials are used as insulation around wires carrying electricity to prevent them from touching each other and reduce the likelihood of electrical shock.If we connect a flashlight cell to a small lamp using two wires we form a complete circuit. Electrons flow from the negative side of the battery, through one of the wires to the lamp, and from the lamp through the other wire to the positive terminal of the battery. Notice that in order for electricity to flow, there must be a complete path for the electrons to follow from the battery to the lamp, and also a return path from the lamp to the battery. When there is a complete path for electrons to flow in the circuit, the lamp will light. If either of the wires is broken, or if the filament in the lamp is burned out, there will not be a complete path, and no electrons will flow.
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July 25, 2008