I don't think I know a science teacher who can resist setting up circuits. We'd been talking about the invention of the light bulb, so it seemed appropriate to let the children have a go at making a circuit. After a trial with aluminium foil (which I've been told does work), we went to plan B and bought some copper wire (coated of course). Each group of children had one battery two wires, a light bulb, and some insulating tape. Eventually all the groups managed to get their light bulb lit up.