Periodically, we get these "Ask a Scienceblogger" questions via email asking for someone to volunteer to answer. Usually I don't feel like I have anything to add, but this one was frivolous enough for me to know something about it... Sorry for the not-a-molecule post, back with the regular content tomorrow.
A square piece of dry paper can not be folded in half more than 7 times. Why?
Actually, it's a myth:
Once, in undergrad, an acquaintance offered up a bet for $100 to anyone who could fold a piece of paper nine times (or some other number greater than conventional myth - eight, maybe). Coincidentally, I had just read the above link and was pretty sure I could find the right paper, so I took the bet. The next day, at the lab, I used a bunch of Kimwipes (very thin tissue, available in large sizes).
Gluing the edges together, I made an enormous piece of tissue paper that, sure enough, I could fold the appointed number of times (if I recall correctly, I went for one extra for an added bit of showmanship). I only ever ran into this guy on the weekends, so I was in the awkward position of carrying this are-you-happy-to-see-me wad of paper all around town on the off chance I'd see him. Fortunately it was only a couple weeks until we ran into each other. I triumphantly unfolded my ~8ftx8ft paper, nine times, as promised (in public, naturally - I forget where).
He never paid up, though!
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How many kimwipes did you use, as it happens a lab adjacent to mine has some and I tried just one of them and couldn't fold them more than 7 times.
It was the big 15x17" (or whatever size is closest to that) Kimwipes - I think I did something like 5, maybe 6 on a side? glued together with elmer's with about 5mm overlap. So ultimately, I got something that was somewhere in the 6-8ft on a side range?
I am pretty sure this gave 9 folds, but it could have been 8. I don't think I had a questionable "Pac-Man" fold at the end (or maybe that was the 9th...)
I'd be curious to hear if anyone tries with the giant paper. Regardless of my fuzzy memory, the first link (and the Mythbusters episode someone mentioned on Katherine's post) definitely demonstrates it's possible with the right size stuff.
Mythbusters did this myth... with smaller pieces of paper, the myth holds true... but they used a piece of paper the size of an aircraft hanger (something like 200 yds on a side) and were able to get like 11 or 12 folds (no "pac man" folds until the last one too).
http://en.wikipedia.org/wiki/MythBusters_(season_5)#Episode_71_.E2.80.9…
Mythbusters, 170' x 220' piece of ordinary 20 lb paper, 11 folds.
In "Mythbusters" episode 71 "Underwater car" they constructed a huge sheet of paper (170 ft x 220 ft) which they folded 11 times.
Cheers
One girl got like 13 or 14 times by using an idustrial roll of toilet paper that was extremely long. the entire thing was like 2 feet tall! Scientifically, or actually, mathematically this isn't really a myth. Because everytime you fold the paper you're folding every fold that you've folded, the area of paper needed grows exponentially to accommodate for the crease size. A normal paper runs out after about 7 folds (128 layers of paper) or less, and after that you have to get incredibly big and increasingly more incredibly big paper to make more folds.