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Energy & Forces - Properties & uses of energy - Electricity - P5G13
This is the Teacher's Guide for this targetThis is the Teacher's Guide for this targetTeacher's Guide

EF-C1.5

1. The children should now understand that a circuit must make a complete loop so that the bulb may light. They will encounter problems with some circuits they make because of the nature of the equipment - it is easy for connections to pop apart or bulbs not to be screwed into the holders tightly enough, and they will have to solve any problems which occur by finding the break in the loop.

Some materials will let electrons pass through them and so will let electricity flow. We call these conductors.

Other materials will not let them pass or slow them up considerably - like wading through treacle or trying to get through a brick wall. We call these insulators.

Make a circuit like this to test materials you can find in the classroom.
The children can use this circuit to test a variety of objects. Choose these to provide a range of different materials e.g. plastic, wood, rubber, metal, paper or card, fabric, glass. Children can fill in Worksheet C13 (G) as they try different things in their circuit. When they have tried a variety of materials they could look at their results and think which type of materials allow electricity to pass and which do not. They should notice that all metals will let it flow and most plastics and other materials will not.

Introduce the words ‘conductor’ and ‘insulator’. They can be remembered mnemonically :-

conductor - as in an orchestra conducting the electrons through.

insulator - the object is insulated from the current.

Watch out for metal objects which have been painted which may not conduct.

Pencil "lead" and charcoal sticks are made from graphite. Graphite is a form of pure carbon, diamond being the other. Although graphite is not a metal it does conduct. Beware of other seemingly non-metallic substances which might conduct e.g. metal based paints can cloud the waters.
4. A switch is a point in the circuit where the loop can be broken or remade to stop or restart the flow of electrons.

A simple switch can be made by using two paper fasteners, a paper clip and a small piece of card. Push the paper fasteners through the card so that the paper clip can be looped across them. Wires can then be attached to each paper fastener and on to the bulb or battery. By swinging one end of the paper clip away from the fastener you open the switch and stop the flow. By swinging it back to touch both paper fasteners the flow is restored.  In the diagram shown above the switch is closed - i.e. electricity can flow.

Allow the children to make a simple switch like this and try it out in their circuit. Let them find out that it does not matter where the switch is placed in the circuit, a break anywhere in the loop will switch off the bulb.

Switch open - electricity cannot flow.

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