The Genii Forum

searching for something completely unrelated I came across this article on the math and physics of the coin thru dental dam. I don't understand the science behind it but found it an interesting curiosity.
https://arxiv.org/pdf/1509.06232.pdf

daniel zuckerbrot

Strange.



is also how I do The Ambitious Card.

I find Martin Gardner's explanation ( see the end of the paper) more plausible--or at least more understandable.

Isn't "The rubber stretches" sufficient?

I learned a new word: "invagination". I haven't figured out where to use it yet, though.

Bill Mullins wrote:I learned a new word: "invagination". I haven't figured out where to use it yet, though.

I invaginated my egg bag to show it empty.

I’d never read Martin Gardener’s presentation before and was surprised that he covered the dime with a quarter to hide the actual “penetration”. I’ve never seen it performed that way. Was he perhaps trying to avoid a “too perfect” situation that points to the explanation?

The other thing that caught my eye was that a spherical object could be used instead of a coin. Has anyone out there tried this? If so, please share any observations (reactions, problems, etc.)

JMD

The trick when done as it was created by Lubor Fiedler is perfection. It is indeed too perfect, but it can withstand that test because the only answer it leads to is unimaginable.

How do we know whether or not this is a hoax? I guess we need a bona fide physicist or mathematician to review this and tell us it's real. I have a little math and I discovered that the coefficient of friction for a hot double lift can be determined by the formula:

Fsmax = μs η
Fsmax = μs mg
Fsmax = (0.75)(700 kg)(9.8 m/(s2))
Fsmax = 5145 kg∙m/s2
Fsmax = 5145 N

Uh ... okay. Are you feeling all right, Bob?

Right now, Jim Morrison's head is hovering just over my monitor, but just his head, and he seems to be telling me something about my dog's vocabulary. Other than that, everything's fine.

What a fun paper! (I wish the manuscripts I have to review were half as entertaining).

One observation (which will make the most sense to those medical) is the inclusion of the name, "Sir Roger Penrose" as being in the informational lineage of one of the authors (cited at the end of the paper).

I also thought it was cool that the dental dam itself was invented during Civil War times and was given "as a free gift to the dental profession" by the inventor, Dr. Stanford C Barnum.

I'm curious where Bob got those 700 kilos...

"Dr. Stanford C Barnum."

Really--"Barnum!"

This has got to be a hoax.

"There's a sucker born every minute." P.T. Barnum

"In the latter part of the 20th century, two were born every minute."-P.J. O'Rourke

Lubor was a scientist: he would have loved all of this.

I hesitate to ask this--but if the rubber breaks during the invagination, are sponge bunnies the result?

Jack Shalom wrote:I hesitate to ask this--but if the rubber breaks during the invagination, are sponge bunnies the result?

Not with a dental dam....