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.
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.