Electricity is the flow of electrons through a substance. Those materials permitting this flow are called conductors; those which do not are nonconductors (or insulators). Among those materials which are conductors, some are better at conducting electricity than others. In this exercise, we will study a number of materials to see whether or not they are conductors. In general, among solid substances, metals are conductors and nonmetals are not. Distilled water is not a conductor. Solutions containing ions (salt water, acids, tap water) are conductors.