Demonstrating how fuses work

Demonstrating how fuses work

ZIMSEC O Level Combined Science Notes: Experiment: Demonstrating the effects of short-circuits and overloads

Aim: To demonstrate the effect of a short circuit/overloading of a circuit on a fuse

Materials: 6 or 12 V battery, copper wires, fuse wire/steel wool strand, switch, car headlamp, torch bulb, switch, 2 nails, wooden block


  1. Set up with circuit with a torch bulb in the circuit
  2. Close the switch and observe the fuse wire
  3. Replace the bulb in the circuit with a car hand-lamp which draws more current than the torch bulb
  4. Close the switch and observer the fuse
  5. Open the switch and replace the fuse wire
  6. Take a wire and replace the bulb with it
  7. Close the switch and observe the fuse

Results and Observations

  • The fuse wire remains intact when a torch bulb is used
  • The fuse blows when the torch bulb is replaced with a car head lamp
  • The fuse also blows when a wire is used to short circuit the circuit


  • Fuses can protect a circuit from overloading/short circuits by blowing and breaking the circuit

To access more topics go to the Combined Science Notes page.