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

```Andrew McLeod wrote:
> A cube of dimensions 1"x1"x1" has a volume of 1" cubed. Each of the faces has an area of 1" squared. If you passed electricity from one face to another, you would be passing electricity along a length of 1" and a cross-sectional area of 1" squared.
> The resistance done so from one side to the other is the length it must travel (1") divided by the cross-sectional area (1" squared) and also divided by the resistivity of the material.
> The resistivity is the resistance measured from one face to another times the cross-sectional area (1" squared) divided by the length.

OK, I think I get it. The "area" refers to the plane along which the
electricity travels. So that if you were to put the probes of the meter
at opposite edges of the cube (top and bottom), the area of the plane
would be 1.41 square inches (Pythagoras and all that). It would only be
1 square inch if the probes were placed at the exact same height on both
sides of the cube. Is that correct?

--
Jerry Baker
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```