Quote:
Originally Posted by wa8yxm
... So the good battery has a nice THICK shell, but the bad battery, it's paper thin.
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It bounces better because it's thinner? By that theory, an aluminum-foil sphere would outbounce a thicker aluminum shape such as a
tea ball.
With all respect, I don't believe it. I think a thinner shell may
reduce the coefficient of restitution, not
increase it. That is, a thinner shell would bounce
less.
Me, I conjecture that gas is evolved inside the shell when the battery is discharged, and that the increased pressure makes it more elastic, like the difference between a deflated basketball and one you've just pumped up.
I can test this. If gas pressure increases within, enough to make it bouncier, the cell should get longer as the pressure pushes the ends out a little. I'm going to mike a new AA, discharge it, and mike it again.
Interesting. The mike shorted it out, of course, so it warmed up a little as I held the mike on it. Started out at 1.9675 inches and warmed enough to get to 1.9680 in the couple of seconds I held the mike on it. After it's discharged, I'll have to let it cool before miking it again.
[Later] Length before discharge, 1.9680. Length after discharge, 1.9730. Longer, but by only about 1/4 of a percent. I don't think that proves anything, except maybe it proves that I'm wasting time and batteries. Oh, well.