Britney Gallivan

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In January of 2002, while a junior in high school, Britney Gallivan demonstrated that a single piece of 1.2km long toilet paper can be folded in half 12 times. The previous limit was believed to be only eight times. Not only did she provide the empirical proof, but she also derived an equation that yielded the width of paper, W, needed in order to fold a piece of paper of thickness t any number (n) of times.

An upper bound and a close approximation of the actual paper width needed for alternate direction folding is:

$W = \pi t 2^{\frac{3}{2}\left(n-1\right)}$

For single direction folding (using a long strip of paper), the required strip length L is:

$L = \frac{\pi t}{6}\left(2^{n}+4\right)\left(2^{n}-1\right)$

Gallivan's story was mentioned on an episode of Numb3rs on CBS in 2005 and on an episode of Mythbusters on The Discovery Channel in 2007. She currently attends the University of California, Berkeley.