Re: [APD] Caution with lead weights -- Or - Ethyl's Nails

[Vaughn Hopkins <hoppycalif at yahoo_com>]

The electric resistance of a cube from one corner to the opposite  
corner would have to be calculated using calculus - the cross section  
area would vary with the "length" of that conductor.  Of course, in  
reality, resistance or conductivity measurements are made using  
cylinders that are very long compared to the diameter.  (We tend to  
call such cylinders "wire").  But, if you are using resistance or  
conductivity to determine what a metal is, by cutting off a piece of  
it, you would have to form that piece into a cylinder or long bar,  
with a constant cross sectional area.  Or you could just try to write  
with the piece - everyone knows that pencils are made with lead,  
right???

Vaughn H.

On Sep 28, 2006, at 8:46 AM, S. Hieber wrote:

> Not really. The area is relevent only as a determinant of the cross  
> section size. The electrons can and will follow lots of diff paths,  
> and the fatter the wire, the more paths (regardless of whether it's  
> flat or round). Following the pipe metaphor, which can only be  
> carried so far, water will run through all of a pipe, not just the  
> short line that can be drawn between the entrance and exit.
>
> sh

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