Forgive the extreme, potentially unnecessary, detail, but I'm trying to include all possible info to account for all possibilities, as this has driven me mad here. I lined a baking pan with Great Value brand Heavy Duty aluminum foil, baked it with nuggets and fries on top for about 20 minutes at 420 degrees Fahrenheit, removed the pan from the oven and the foil from the pan, and ate the food off the foil, adding ketchup and honey mustard onto the foil as well. I wadded up the foil with the crumbs and condiment smears on the inside of the wad. I set the wad down on my coffee table, and it repelled onto the opposite end of the wad. I tried it again, and it did it again, much like magnetic repulsion. However, I know aluminum isn't magnetic in the conventional sense, and my table surely isn't either. I tried it on the floor. It happened again, as well as on my couch, counter, and lunchbox. All give the wad a visceral, magnet-like reaction. The wad refuses/is unable to remain right-side up. After going down several internet rabbit holes, I am now worried that my apartment building may be giving me cancer, so I ask you all--what is going on here, and is it potentially hazardous to my health? I took a video, linked here.
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$\begingroup$ Try against a known magnet. If it is magnetic force, there should also be attraction. $\endgroup$– Gyro GearlooseCommented Jan 22 at 23:16
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$\begingroup$ Pretty sure the explanation is static charge. See this Youtube video of static charge experiments, some using silver foil. youtube.com/watch?v=ViZNgU-Yt-Y&t=49s $\endgroup$– KDPCommented Jan 22 at 23:18
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$\begingroup$ To test against @KDP s plausible explanation, discharge it by contacting it against a water tap. No matter what, it remains a mystery how it could get the electric charge, and keep it even after you handled it. $\endgroup$– Gyro GearlooseCommented Jan 22 at 23:31
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$\begingroup$ Maybe the OP is the source of the static charge, shuffling on the carpets? Remember Electric Man episode of Family Guy? youtube.com/watch?v=iBkQY3mh8PA&t=40s $\endgroup$– KDPCommented Jan 22 at 23:44
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$\begingroup$ @KDP I don't think you can gather enough static charge in an innocent way to create mechanical repulsion in the way the OP describes it. It would really be interesting if that could be reproduced. $\endgroup$– Gyro GearlooseCommented Jan 23 at 0:17
1 Answer
Nice video!
Hypothesis: The crumpled foil is simply settling toward a position where its center of gravity is lowest, as all things tend to do in a gravity field.
The ball looks “lively,” which suggests that a different strong driving force is dominating, such as magnetism. That is, we’re familiar with magnetism making metal objects roll and slide and hop laterally.
We’re perhaps not as familiar with objects that are simultaneously very light and very stiff and nearly—but not completely—spherical. This answer discusses how that unusual condition arises with crumpled foil wads.
I think you’ve found an intermediate configuration of crumpling where the ball doesn’t sit as expected or roll as expected. It’s off balance when you set it down, and the kinetic energy gained when it falls from its original position allows it to ”skitter” across several other orientations before finally oscillating and settling down into a stable orientation. (This is completely harmless.)
Denser objects such as solid metal (and note that even solid aluminum is very light) wouldn’t hop around in this manner. Softer and more compliant objects would tend to settle in place and would also damp out more of any motion. More regular shapes would roll in a more familiar manner.
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$\begingroup$ +1 This explanation seems plausible, as after watching the video again, the foil ball does appear to initially roll and quickly stop at a stable position. $\endgroup$– KDPCommented Feb 18 at 1:15
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$\begingroup$ The "+1" is implemented by clicking on the up arrow :) $\endgroup$ Commented Feb 18 at 1:18
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$\begingroup$ Thanks for the thorough response and apologies for the late reply! While it is surely possible that the composition of the ball is just perfectly imperfect enough in a way to create this behavior outside of electromagnetic interference, it strikes me as odd that it would roll from the flat, more stable side to the round side to find stability--not to mention how I could feel it pulling from between my fingers and the way it would jerk so abruptly from a stationary position. I'm not sure center of gravity puts this one to rest just yet.. though I'm no longer worried about cancer at least hah! $\endgroup$– FoxholeCommented Feb 18 at 1:29