Video: Watch this demo
Description: This demonstration shows how a wires electrical resistance changes with temperature.
Materials:
- 2V Lightbulb
- Thin Wire Coils
- DC Power Supply
- Propane Blowtorch
Procedure:
- Connect the circuit as shown above; the lightbulb, coil, and DC power supply should be in series
- Turn the voltage on the power supply to 2V
- With the propane torch, heat the coil just until the coil becomes red; the light should dim
- Turn off the power supply when finished
Notes:
- Avoid overheating the coil; the coils are fragile and will break if the flame is on them for too long
- If more coils are needed, 32 gauge wire works best
28-F2
