Conductors and Insulators

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Conductors are materials that allow an electric current to flow through them easily. Most metals are good conductors.

Substances that do not allow electric current to flow through them are called insulators, nonconductors, or dielectrics. Rubber, glass, and air are common insulators. Electricians wear rubber gloves so that electric current will not pass from electrical equipment to their bodies. However, if an object contains a sufficient amount of charge, the charge can arc, or jump, through an insulator to another object. For example, if you shuffle across a wool rug and then hold your finger very close to, but not in contact with, a metal doorknob or radiator, current will arc through the air from your finger to the doorknob or radiator, even though air is an insulator. In the dark, the passage of the current through the air is visible as a tiny spark.

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