Something you probably haven’t considered recently: just how many times can a sheet of paper be folded?
Conventional wisdom says about seven times, maybe eight, because the more times a sheet is folded, the thicker it gets. Once the resulting stack becomes thicker than it is long, it can no longer be folded. Consider a sheet of paper about .1 millimeter thick. After 42 folds, the stack would be over 439,800 kilometers high — greater than the average distance between Earth and the moon, according to Boundless Brilliance, a Los Angeles-based STEM education nonprofit.
And yet, in 2002, Britney Gallivan, then a junior in high school in Pomona, California, set the Guinness World Record by folding a single piece of paper in half 12 times. Not only that, she wrote equations to calculate how many times any piece of paper can be folded in half. This included folding both in a single direction and multiple directions. These equations were published in her book How to Fold Paper in Half Twelve Times (Historical Society of Pomona Valley, 2002; unfortunately, it’s now out of print).
How did she do it? She found that in order to fold a piece of paper in half many times, a long thin sheet is needed She ultimately set her record with a sheet of tissue paper she found online that was 4,000 feet (1,219 meters), more than three-quarters of a mile or over a kilometer long. Setting the record took about eight hours crawling in a long corridor in a shopping mall in California.
Of course, since Gallivan got the record, others have claimed to have folded paper more than 12 times, although various shortcuts, like pleated fan folding, have been used. Such shortcuts miss the point of the mathematical geometric progression of paper folding. Still, she expects her record to be broken someday. If it ever is, one thing will be for certain — it will be a very thin sheet of paper.
For the complete story, see “How Many Times Can You Fold a Piece of Paper in Half?” by Charles Q. Choi at https://www.livescience.com/how-many-times-can-paper-be-folded?