What affect does the number of bulbs in a series have on the brightness of each bulb?
Discover the Answer for Yourself
The materials needed for this investigation can be purchased at an electronics store, such as Radio Shack.
size C battery, 2 flashlight lamps with screw base, “C” battery holder with color-coded wire leads, 2 flashlight lamp holders with screw base, 4-inch (10-cm) strip of 20-gauge insulated single strand wire, wire cutters,
screw driver (type that fits terminal screws on lamp holder)
Caution: Do not use an electric source other than the one C battery and disconnect the battery after about 5 seconds. Touching the wires will not shock you, but if the battery is connected for an extended period, the wires will get hot and can burn your fingers.
1. Place the battery in its holder.
2. Use wire cutters to strip about 1/2 inch (1.25 cm) of insulation off each end of the wires connected to the battery holder.
3. Connect one of the wires from the the battery holder to the lamp holder. Do this by using a screw driver to loosen one of the screws on the lamp holder. Wrap the metal end of the wire around the screw, and then tighten the screw to hold the wire in place.
4. Hold the other wire from the battery holder so that its metal end touches the screw on the opposite side of the lamp holder. Observe how bright the bulb is.
5. Using the wire cutters, strip off the insulation at the ends of the 4-inch wire. Use this wire to connect two lamp holders as shown.
6. Repeat step 4.
When the lamp holders are connected to the battery, both bulbs glow, but not as brightly as when only one bulb was used. This is because each lamp uses part of the electric energy flowing through the circuit.
How does removing a bulb in a series circuit affect the flow of electricity?
Discover this for Yourself
Remove one of the bulbs, and then repeat step 4 in the above procedure. What happens?