For a class of 20. A light source from an overhead projector or a small lamp. A and B. Give each student one battery and one Christmas light. Without explanation, tell them to make the Christmas light come on. Allow 5-10 minutes for this activity, then have students demonstrate and discuss ways they were successful or unsuccessful in getting the lights to come on.
Electricity travels in a path called a circuit.
Wires must be correctly attached to the battery's contact points to complete a circuit. Demonstrate contact points using two batteries and show how two batteries, together, can make the 1.5 v light come on. Explain the use of a battery holder and its contact points. Demonstrate making the light come on using the battery holder. Show students the circuit set-up and ask them why the light doesn't come on.