For this project you’ll build a simple circuit with a switch that allows you to control the flow of electricity. The individual parts can then be used later for other experiments. Materials you will need:
How to Build the Circuit:
- Energizer® Power Pack
- Spring-tension wood or plastic clothespin
- Number 22 insulated copper bell wire
- Small block of wood
- Nail, thumbtacks, and paper clip
- 3-volt flashlight bulb
- 1. Wind one wire from the Energizer® Power Pack around a thumbtack. Hook a paperclip around the tack and press it into the wood block. Cut a new wire, strip both ends, and wrap each end around two more thumbtacks.
Press one thumbtack into the wood so that when the paperclip rotates it will make contact and close the switch. Press the other thumbtack into the location where the light bulb will be held. Wrap the other wire from the Energizer Power Pack around the light bulb.
- 2. Position the clothespin so that it will hold the bulb directly above the thumbtack and then nail it into the wood block. Insert the bulb into the clothespin so that it is making contact with the thumbtack.
When the circuit switch is open (Figure 2) current does not flow to the bulb.
- 3. When you rotate the paperclip and make contact with the second thumbtack you close and complete the circuit, current flows through the circuit and lights up the bulb
- The switch, bulb holder, and portable power pack are a complete circuit and arrangement of conductors; they allow the passage of electric current through the wire.
Metal objects make the best conductors. Copper, brass, steel, or a strip of tin can have many free electrons capable of being moved along by an electromotive force such
as voltage from the battery. In insulators, such as the wire covering, electrons do not move easily, so you can work with electricity safely.
Alternate: Scientific knife switches, bulbs, bulb holders, and cell holders are available commercially. These are used to illustrate most of the other experiments throughout this site (Figure 4).