======Fuse with Steel Wool======


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**Materials: **{{$demo.materials_description}}\\
**Difficulty: **{{$demo.difficulty_description}}\\
**Safety: **{{$demo.safety_description}}\\
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**Alternative titles:** Circuit Protection with Steel Wool
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====Summary====                   
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====Procedure====  
  - Set up a simple circuit with a power source, a light bulb, and a holder for a small piece of steel wool to act as a fuse.  
  - Insert a few thin strands of steel wool into the circuit in place of the fuse.  
  - Turn on the circuit with the light bulb connected; the bulb lights normally.  
  - Create a short circuit (for example, bypass the bulb).  
  - Observe as the increased current causes the steel wool strands to glow red-hot and melt, breaking the circuit.



====Links==== 
Gr8 Electrical Fuse Wire of steel wool - Peter “mac” McEwan: 
{{youtube>xuCQ4eZmRSw?}}\\

📄 How fuses work - IOP: [[https://spark.iop.org/how-fuses-work]]\\


====Variations====
  * Try different thicknesses of steel wool to see how much current they can handle before melting.  
  * Replace the bulb with a small motor or other load to compare how the fuse responds.  
  * Compare steel wool with a thin copper wire to highlight why certain materials are chosen for fuses.
  * Use commercially available low-current fuse wire.



====Safety Precautions==== 
  * Use low-voltage DC power (e.g., batteries) to reduce risk.  
  * Perform the demo in a fireproof tray or on a non-flammable surface.  
  * Do not use mains electricity for this demonstration.  
  * Do not touch the steel wool immediately after it burns—it will be hot.




====Questions to Consider====
  * Why does the steel wool melt when the circuit is shorted? (Excess current produces heat through resistance.)  
  * How does this relate to the purpose of a fuse in a household circuit? (A fuse is designed to melt and break the circuit before the wiring overheats.)  
  * Why is steel wool suitable for this demonstration? (It has higher resistance than copper, is thin, and heats up quickly.)  
  * What would happen if you used a thicker piece of steel wool? (It would take longer to heat and may not act as an effective fuse.)