What is a conductor?
A conductor is a material that lets electricity or heat flow through it easily. Metals like copper, silver and aluminum are good conductors, while rubber, plastic and glass are insulators.
In metals, some electrons are not tightly bound to atoms and can move freely. This sea of electrons carries electric current and also transfers heat quickly, which is why metal spoons get hot in soup. Silver is the best electrical conductor, but copper is used for most wiring because it is cheaper.
Insulators, like rubber, plastic, wood and glass, hold their electrons tightly, so electricity cannot flow through them easily. Electrical wires are made of copper surrounded by plastic insulation to keep the current inside and protect people from shocks.
In between and beyond
Semiconductors, such as silicon, conduct electricity under some conditions but not others. They are the basis of computer chips and solar panels. Superconductors, when cooled to very low temperatures, conduct electricity with no resistance at all and are used in MRI machines.
Did You Know?
Pure water is a poor conductor, but tap water and seawater conduct electricity because of dissolved salts, which is why electricity and water are dangerous together.