ELECTRIC BASICS: Where do charges move?

Materials that allow charged particles to pass through easily are called conductors. They have low resistance.

Materials that keep charged particles from passing easily are called insulators. They have high resistance.

A third category of materials allows some but not many charged particles to pass through. These semi-conductors, with neither high nor low resistance, are often used in computer and photovoltaic technologies.

Some of the most well-known conductors are metals like silver and copper. The electrons in these metals detach and move easily from one atom to the next. An electric current pushed by an electric voltage can be made to travel a distance through a long, thin wire.

The wires in your walls, inside your lamps, and elsewhere are mostly made of copper so that the electrons can flow. They are covered with insulating materials like rubber and plastic which keep the current from leaking out of the wire. But metals are not the only good conductors. Certain liquids like salt water and acids also let electrons pass through easily. These liquids are often used inside of batteries.

NEXT: Voltage and Resistance