Making a bulb light


The simplest way of making a bulb light is to make a very simple circuit like the one in the diagram above. The battery is the source of the electrical energy. Notice that the connectors are strips of aluminium metal. They provide a path for the electricity to flow along and when the bulb lights it also shows us that a current of electricity is flowing. The current will only flow when all parts of the circuit are joined together. If there are any gaps electricity will not flow.

Does it matter how wires are attached to a battery?
Yes it does. Electricity will only flow if one wire is attached to the metal cap, or terminal, at one end of the battery and another wire is attached to the opposite end of the battery. If you put the ends of both wires on the same terminal of the battery electricity would not flow. If you attached both wires to the side of the battery electricity would still not flow.

Why batteries can be used for investigations but mains electricity cannot.
A battery is a small store of electricity at a low voltage. The power of the electricity in most batteries is only small and is harmless. Mains electricity comes from a huge machine called an electric generator at a power station. It produces a large amount of electricity at a high voltage (240V). This can kill people if it is not used safely.

Why are batteries so useful?
They are portable supplies of electricity. A piece of equipment that uses batteries does not need to have a cable connecting it to the mains. It can be used a long way from the main electricity supply. Think how difficult it would be to use your torch outside if it was connected to the mains.

Does a car have a battery to make its lights work?
Yes, but it is a much larger battery than the ones you use for your classroom investigations.
A car battery does not contain dry paste like small batteries but has acid inside it.
A car battery does not just provide electricity for the lights. It provides electricity for the starter motor, indicators, horn, windscreen wipers, radio and the computer that modern cars use to make them run efficiently. Car batteries must never be used in your classroom investigations because they supply too much electrical power.