: Hey Ed,
: I was curious if you have found any difference in conductivity of the
: metals after they have been shrunken.
: I had thought that the volume was changing, but that should mean that the
: density goes up(right?), but you say above that density and mass stay the
: same, so that should mean the volume stays the same as well. Are the
: coins simply being misshapen, and not shrunken at all?
: Mass=Volume*Density, right?
Interesting question! We have not measured the electrical conductivity of coins before, or after, shrinking. Unfortunately, we do not have the appropriate equipment to accurately measure the bulk resistivity of coins.
It is known that the alloys in shrunken coins develop a finer crystal grain pattern and they also become significantly work hardened. These physical changes usually result in an increase in bulk resistivity for many nonferrous alloys. The volume of a shrunken coin is the same as before. As it is reduced in diameter, it becomes thicker. So, "reshaping" is probably more accurate than "shrinking... :^)
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