Activity

Generator lighting a bulb

Summary
Use a motor in reverse to briefly light a low voltage bulb.
Science content
Physics: Electricity, Electromagnetism (7)
Earth/Space: Sustainable practices, Interconnectedness (2, 5, 7)
Materials
  • hobby motor, ideally with wires attached
  • super red low voltage LED bulb (less than 2V)
Procedure

Attach the motor wires to the pins of the LED bulb. First try the black wire connected to the short pin and the red wire connected to the long pin.
Turn the motor shaft to make it rotate as fast as possible - a short burst of a turn is most effective, so use the hand and the direction that can do this most easily.
If the bulb does not light, reverse the bulb (so that the black wire is connected to the long pin and the red wire is connected to the short pin). Keep the direction that the motor shaft is turned the same.
The bulb lights from the small amount of electricity being made by the reversed motor.
A motor in reverse is called a generator, and converts motion energy into electricity. The electricity generated in this way can only light a small bulb. Generators turned by a wind or water turbine are much larger and generate more electricity.

Grades taught
Gr 6
Gr 7