In my early childhood we spun coins instead of flipping them; we found we lost many coins that were flipped, so we resorted to spinning them. I remember distinctly spinning a nickel and having it stop on its edge.
I know the probability for flipping coins is 50/50, but how about for spinning them? Is there a margin of error associated for this “once in a blue moon” event.
BTW, this actually happened, I have witnesses.
Most American coins will flip fair (close enough to 50-50 that one can’t really tell the difference), but most do not spin fair. An individual coin can easily have a spin bias of as much as 80-20. Which way the bias goes, and how large it is, varies from one coin to another (i.e., not all quarters go the same way), but it’s fairly easy to determine which ones have an extreme bias. So be very suspicious of people who want to use their “lucky coin” for a spin. Or alternately, be one of those people, and win a bunch of bar bets.
Incidentally, I’ve also seen a flipped coin (also a nickel, unsurprisingly) land on edge, so it’s possible. If that happens, you just flip it again. Or take it as a sign that you’re supposed to pursue some obscure third alternative.
All these years later, Cooper has spent the bills and is down to coins!
I would guess it would depend greatly on the method used to spin it. I would think that someone with the proper expertise could design a robot that would spin a coin so that it stayed upright quite often. As far as humans, though, I’d imagine it happens about as often with flipping, if not less.