Conductors and Insulators: Which Materials Let Electricity Through?

Look at a plug on any electrical cable. You will notice two different parts: shiny metal pins and a coloured plastic casing around the wire. Why do you think engineers chose TWO different materials? What job might each one be doing? Hold that thought — this lesson will give you the answer.

Electricity is a flow of tiny particles called electrons. These electrons can travel through some materials easily — but other materials stop them in their tracks. A conductor is a material that lets electricity flow through it easily. Most metals are good conductors. Copper is one of the best — that is why the wires inside cables are made from copper. When electrons meet a conductor, they pass through it quickly, like water flowing through an open pipe. An insulator is a material that does NOT let electricity flow through it easily. Plastic, rubber, wood, and glass are good insulators. The electrons cannot pass through them, so electricity is blocked. The coloured plastic around a wire is an insulator. It keeps the electricity safely inside the wire and stops you getting a shock when you touch the cable. Here is a simple way to remember the difference: conductors CONNECT the flow; insulators INTERRUPT the flow. Both conductors and insulators are useful. We NEED conductors to carry electricity to our lights and devices. We also NEED insulators to keep us safe from that electricity. Real-world example you can observe: Look at any electrical cable at home or at school. The shiny copper wires inside are the conductor. The coloured rubber or plastic coating on the outside is the insulator. Engineers always use both together.