Electricity travels easily through electrical conductors, like metals. Materials that do not let electricity pass easily through them are called electrical insulators. In this lesson, you will learn more about electrical conductors and insulators.

You have probably learned that all matter is made of electrons. Electrons are always moving, but they move at various speeds. In materials such as metals, the electrons can move around fairly easily. In other materials such as glass, the electrons cannot move around easily.

The ease an electron can move within a material is known as electric conductivity.

Materials whose electrons can move fairly easily are called conductors.

Materials whose electrons cannot move easily are called insulators.

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Conductor

A conductor is a material that allows charges to flow easily throughout the material.

Example: copper

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 Insulator

An insulator is a material that does not allow charges to flow easily throughout the material.

Example: rubber

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Below are some common examples of conductors and insulators.

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In an earlier lesson, you learned that electricity is the movement of electrons along a path. Taking this a step further, any of the items on the conductors list allow an electric charge to flow through them; any of the items on the insulators list do not allow an electric charge to flow through them.

An example of how electrons move can be shown by filling a tube with a row of marbles. Think of each marble as an electron. If you add a marble to the left end of the tube, all the other marbles roll forward and one pops out at the opposite end. Each individual marble does not move very fast, but the energy transferred through all the marbles to the one that pops out the end is quite great. Electricity moves through a conductor like the marbles in the tube. The overall effect of the moving electrons happens at a speed of about 300,000 km per second! This is the speed of light!