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Sagging Wire


Displays current-created heat and its thermal effect on a wire

Current flow Power from electricity (P = V*V/R) Heat expansion


To demonstrate current-created heat and it's thermal effect on a wire


  • Nickel wire (currently missing)
  • 200g weight
  • Power supply with two leads
  • Two stands


  1. Tie the nickel wire between the two stands at a considerable distance (The longer the distance, the more sagging will occur
  2. Place the weight in the center of the span
  3. Attach the alligator clips of the leads to the ends of the wire
  4. Flick the power supply switch to 12 volts and turn the knob clockwise to its maximum
  5. The wire will start sagging to a maximum point
  6. Turn the power off and the wire will return to its original position


If the wire is over heated, it will break. If the wire starts to glow red, it can break and possible ignite something. (

Demo room information

Location —-
Maker Unknown
Current State Working
demonstrations/4_thermodynamics/4a_thermal_properties_of_matter/sagging_wire/start.txt · Last modified: 2019/04/26 22:46 by demoroom