Resistance in a Wire (coursework Evaluation)

[Jozers]

To get the full marks for my gcse coursework "how does length affect the resistance in a wire?" I need to provide an alternative experiment that I could perform if I were to redo the investigation. I have already calculated resistance in circuit using ohm's law and predicted results using the R=ρL/A. Does anyone have any suggestion to what I could do? I haven't had any luck researching this, although my teacher hinted that I could do something with variable resistor to control the resistance but I have no idea how. Please remember this must relate to the length not wire temperature or cross-sectional area.

Thanks
Jozers

 

[OlderDan]

To get the full marks for my gcse coursework "how does length affect the resistance in a wire?" I need to provide an alternative experiment that I could perform if I were to redo the investigation. I have already calculated resistance in circuit using ohm's law and predicted results using the R=ρL/A. Does anyone have any suggestion to what I could do? I haven't had any luck researching this, although my teacher hinted that I could do something with variable resistor to control the resistance but I have no idea how. Please remember this must relate to the length not wire temperature or cross-sectional area.

Thanks
Jozers

Have you ever used one of those big slide wire rheostats as a variable resistor?

http://www.thesciencefair.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=1856-2&Category_Code=ET

Knowing how it works might give you some ideas. You might also want to find out about the Wheatstone bridge if you have not already encountered it.