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resistance and temperature question

How would you design an experiment to see the variation of resistance with temperature?
Thanks
Original post by JenniS
How would you design an experiment to see the variation of resistance with temperature?
Thanks


Why dont you tell us what you would do and then we'll correct/improve your answer ?
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JenniS
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Original post by Ari Ben Canaan
Why dont you tell us what you would do and then we'll correct/improve your answer ?


erm. Connect up a circuit with an ammeter in series and a voltmeter in parallel with a piece of wire. Measure the voltage and current through the wire at a number of different temperatures (not sure how to heat the wire), then calculate the resistance at each temp from your current and voltage measurements. Plot a graph of resistance against temp and look at the relationship?
Original post by JenniS
erm. Connect up a circuit with an ammeter in series and a voltmeter in parallel with a piece of wire. Measure the voltage and current through the wire at a number of different temperatures (not sure how to heat the wire), then calculate the resistance at each temp from your current and voltage measurements. Plot a graph of resistance against temp and look at the relationship?


Alternatively, you could use an ohmmeter connected to a measured length of wire. First measure the resistance at room temperature. Make sure to leave the wire connected for some time so as to allow the reading to stabilise.

Disconnect the wire and let it cool down. Heat the wire in an oven so as to ensure equal heating. Remove it, measure its temperature with a thermocouple and quickly connect it up to measure the resistance.

Repeat.
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JenniS
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thanks but what's a thermocouple?
Original post by JenniS
thanks but what's a thermocouple?


A thermocouple is a highly sensitive thermometer. It has a very low thermal capacity which means it responds to temperature changes VERY quickly.

Its basically made up of two pieces of completely different metals joined together with a voltmeter.

http://www.omega.com/prodinfo/thermocouples.html

Just read the first paragraph.
Or take a look at page 8 here for an alternative approach...
http://physics.slss.ie/resources/downloads/ph_pr_electricityexperiments.pdf

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