Electrical Conductors

Abstract

Some solids are good conductors of electricity while others are poor conductors. In solids, electrical current is usually a current of electrons. Some solids such as silver, copper, and aluminum have many electrons that are either free or loosely bound to the atoms. These electrons are available for current flow so these solids are good conductors of electricity. In some other solids, such as glass and wood, the electrons are more tightly bound to the atoms, and thus are not available for current flow. These are poor conductors of electricity and are sometimes called insulators. The temperature of a solid usually affects its electrical conductivity. Temperature is a measure of the average kinetic energy of the atoms in a substance. Some of this energy is vibrational energy of the atom as a whole, but some is possessed by its electrons. Some atoms will have a greater amount of energy than the average and others will have less than the average. In even the poorest conductors, at room temperature, some of the atoms will have enough energy so that a few of their valence electrons are energetic enough to be free, and thus available for electrical conduction.