Determine what the minimum requirements are to light an incandescent bulb.
mini incandescent bulb, bulb socket, battery case, D cell batteries, connecting wires
Design a circuit that contains the minimum materials needed to light an incandescent bulb. (You do not need to use all of the investigation 1 materials for this circuit.)
1. Build a circuit with three D-cell batteries and two mini incandescent bulbs in a closed loop. Break the loop by disconnecting a wire from one end of the battery holder and then reconnect it. Do both bulbs appear to light at exactly the same time? Do you believe that both bulbs actually light at the same time?
2. Reconnect the wire to the battery, and then disconnect a different wire somewhere else in the loop. Try this in several places. Is there any place where you can break the loop and one or both of the bulbs will still stay lit?
3. Unhook one of the wires and bring it as close as you can to where it was connected without actually making contact. Do this slowly and carefully, watching the space between the wire and the contact point. Do the bulbs light? Do you think actual contact is needed for the bulbs to light continuously?