Conductivity of different types of metal wires (help with my kid's science experiment)
Posted on 2013-05-15
I'm helping my kid with a Science project and to be honest I need a hand here...
The experiment he chose was to test the conductivity of different types of metal wires (we have copper, steel, aluminum, and nickel)
We put an RC battery at one end (7.2 Volt NiCd, 1800 mAh) , grounded the negative of the battery and Volt meter, and then basically stuck different wires into the positive clip of the battery and tested the wire at the other end with the volt meter to measure the Volts DC output.
I had thought since different metals have different conductivity that there would be some difference among the wires, with copper showing the most conductivity.
But - in all cases except for the aluminum wire, the measurements of the output out the wires were exactly the output out the battery directly.
So the copper, steel and nickel wires all had the same conductivity.
That wasn't what I was expecting so I'm a bit stumped. This doesn't invalidate the experiment I don't think, as long as we can come up with a good explanation for why this is.
Problem is I have no clue. Is it because at such low battery power they are all equally conductive? (except the aluminum). I need to somehow explain why they all showed no resistance (except aluminum)
Any help/guidance/explanation would be much appreciated.