LordVger

Yeah so me and a buddy were talking the other day about John Conway, the mathematician. He tells me that Conway discovered that if you place pennies on their edge on a table and then bang the table, the majority of the coins would fall on one side (tails? heads?, whatever, but they'd mostly be one or the other). According to him, it's because the edges of a coin are slightly bevelled. This seemed true, since ejecting a coin from its restraining collar would work much better this way, I guess.

So is it true that the collars are bevelled?

satootoko

I really doubt the authenticity of that tale.

John Conway is a Cambridge mathemician well know for his interest in games but none of his biographies that I've tried to understand even hint that he had an ability to make small coins stand on edge, or an interest in doing so.

If he ever did really play with coins, it was undoubtedly real "pennies" and not U.S. cents, and I don't have enough of those to analyze whether or not their edges are slightly angled. Under 10x magnification I can't detect any pattern of angled edges on Wheaties or Memorial Lincoln cents.

But, speculation is just that, and perhaps we will learn the truth as a result of an e-mail inquiry I have dispatched to Prof. Conway.

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Roy

SilverDollarMan

R we bored today? lol .....joking!

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Thx Alot
Just Learning!
Gary Lawson

KLJ

Actually, I could see Conway's theory working, but it could vary between British and American pennies. How? Does Lincoln's head contain a greater percentage of the copper of the coin than the Queen's (or King's) head does? Or vice-versa. It would probably also matter where you hit the table in relation to the coin. For example, I could see it having an influence on the outcome if Conway always hit the table 2 inches away from the obverse.

In other words, there might be something to it, but the difference is what pollsters would call "statistically insignificant."

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Soli Deo Gloria!

huntsman53

I think that this is more of a factor of top heavy or bottom heavy or in other words, one side of the coin outweighs the other! Therefore, if the coin is stood on it's rim and disturbed in some way, then it is more likely to tip over and land with the heaviest side down. As to which side (Obverse or Reverse) is the heaviest on a Lincoln Cent, is anyone's guess!


Frank

LordVger

Well see, this guy that told me the story is a respected math guy himself, PhD and all. Plus, he's a total genius. Also, he was my advisor for my masters degree, so he's much my mentor. Not world famous, but still a very highly regarded algebraist and far and away the most intelligent dude I've ever met.

When it boils down to it, though, I'm really just asking if the restraining collar is bevelled, and I won't say "penny" again, I was just being colloquial, seein' as how I hail from Missouri and all.


vger

Morgan

LordVger-

The rim on a penny may apear flat and straight but have you ever looked at it through intense magnification, say 20x or more?

The point is unless the coin is uncirculated and not damaged from the minting process it may make very little difference if the obverse applies more moment of inertia than the reverse or vise a versa.

The reason I say this is the rim, edge, is not perfect. No matter how new a cent looks the edge of a circulated coin is disrupted and prone to fall a certain way. That way may alternate at any point along the rim. The reason I say this is the images on the obv and rev of a normally struck coin are recessed further than the edge of the rim. This means the minute change in mass between the obv and the rev have little bearing on the direction. In most cases the edge is prone to one side or the other.

By stricking the table you cause the coin to jump due to the vibration of the table. This jump causes a subsequent impact between the cent and the table. Any small imperfection will cause the coin to be deflected one way or the other. Even air movement, which is normally not sufficient to fell the static coin, can influence the coin during the jump and cause the coin to fall a certain way. Basically there are way to many things happening, and the coin will fall to which ever direction the forces make it fall. Especially if the striking force transmits a horizontal force as well.

Now if we assume the edge is perfect and the table is perfect and all other external factors are constant then and only then can we say that the prefered direction is due solely to the rev and obv. This is however due more to thier relative position about the center line of the coin than anything else. If you look at a coin from the edge and can determine the exact center line that would split the coin in two you can, with one more peice of information, calculate the direction of prefered fall. This last peice is the center of mass. When determining the center of mass the mass the obv and rev masses do come into play, however the strick is still more important. BY strick I am refering to the depth of srtick of each face.

If the obv is struck deeply and the rev is not the bulk of the metal will be on the reverses half of the center line causing the coin to prefer to fall rev down. If the obv is weak and the rev is deep the opposite happens. Numerous combinations are possible especiall when you allow for grease filled and struck through errors to be used.

Basically what I am trying to say is the condition of the edge, impact, and the table have considerably more influence than the strike, which has more influence than the mass of the images.

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Of course this is my opinion so think what you will and say what you wish, Its your right.

LordVger

Morgan

Thanks, although it's easy to thank a person who agrees with you!!!

My first thought was precisely that, and that's why I said, "I bet that's true of only pennies before 1982." (I, uh, mean cents)

More copper on the obverse, they'll tend to fall with the reverse up.


vger

Ron Ferguson

Figure this one out - My wife wanted me to take her out to some place expensive. Now is is mad cause I took her to the gas station. I just can't please her.

Morgan

LMAO

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Of course this is my opinion so think what you will and say what you wish, Its your right.