You put the headphones in your bag in a tidy coil, but when you pull them out, they’re a snarled mess every time. It may seem like a personal curse, but a new study shows that it’s just physics in action.
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Dorian M. Raymer and Douglas E. Smith of the University of California, San Diego worked out the physics of random knotting by putting lengths of string into a contraption resembling a miniature clothes dryer that spun the loose string around. A mere ten turns, they found, had a fifty-fifty chance of putting a knot in a piece of string. The longer it tumbled, the greater the chance of a knot forming.