The students built series and parallel circuits with D-cell batteries and light bulbs to see which configuration would cause the battery to drain faster. They found that after 28 minutes, the light bulbs in the parallel circuit still shone brightly, while the series circuit lights were dimmer and one was out, indicating the battery lasted longer in the parallel configuration. They concluded more experimentation is needed to definitively determine which circuit drains a battery most slowly.

1. Will a D-cell last longer in a series or a parallel circuit? By Amy and Tim

2. Will a D-cell last longer in a series or a parallel circuit? Parallel circuit Series circuit

3. Prediction We predicted that the series circuit will last longer because when you add more light bulbs, it will drain the D-cell faster in the parallel circuit.

4. Plan (steps) Build a series circuit with 1 new battery, 1 battery holder, 3 wires, 2 light bulbs and 2 light bulb holders. Build a parallel circuit with 1 new battery, 1 battery holder, 4 wires, 2 light bulbs and 2 light bulb holders. Place the batteries into the series and parallel circuits to connect the circuits. Keep the batteries in the circuits for one minute. After one minute record how the bright the light bulbs are on a 1-5 scale. 4 3

5. Results After 28 minutes, the light bulb in the parallel circuit was brighter than the series circuit. In the parallel circuit, the two light bulbs still shone brightly. In the series circuit, one light bulb didn’t shine at all and the other was very dim.

6. Conclusion We claim that the light bulbs in the parallel circuit shone more brightly. We can prove that by looking at both of the circuits now and seeing which one is brighter. Next time we should label the D-cells. We still wonder in which circuit the battery will last the longest.

7. Real world uses If you want to have fun with your circuits, ask your parent to tape a series or parallel circuit to the ceiling and see if it will light up the room.