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Electrical conductors and insulators

In previous steps we learnt that electricity is a flow of electrons through an electrical conductor. But what is an electrical conductor?

Some materials allow electrons to move freely through them. These are electrical conductors. That flow of electrons creates an electrical current in a circuit.

Other materials hold electrons tightly together which inhibits a flow of electrons. These are electrical insulators. Common examples are rubber, plastic and glass.

All metals conduct electricity, however some conduct electricity better than others. Copper is highly conductive and is commonly used in electrical wiring. However, pure lead does not allow electrons to move as easily, it creates more resistance.

Some non-metals are also electrical conductors. Tap water, graphite, animals and plants are all electrical conductors. In a classroom, the discovery of tap water and human electrical conductivity is also an opportunity to discuss electrical safety.

Contrary to popular belief pure water does not actually conduct electricity, however tap water does. Water from the tap is full of impurities which have been added for numerous reasons. Some of these impurities contain ions (atoms which are charged as they have an unequal number of protons and electrons) and these turn the water into an electrical conductor. Sea salt contains ions therefore sea water is also an electrical conductor.

Electrical equipment is carefully constructed using electrical conductors and insulators to ensure safety and efficiency.

Identify

Identify the electrical conductors and insulators in the photo of an electrical plug below. Consider where else we may see electrical conductors and insulators being used for a purpose.

Electric plug opened (UK mains appliances) - with metal contacts where wires are screwed to the pins and a plastic outer shell

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This article is from the free online course:

Teaching Primary Science: Physics

National STEM Learning Centre