Flashback Friday: Physicists finally explain why your earphones are always tangled.

Photo: Flickr/Steven GuzzardiThere are few day-to-day events that send me into a rage as quickly as a pair of tangled earphones. As soon as I put them down, they somehow thread themselves into an unholy mess. And don't even think about putting them into your pocket or bag. So how do headphones (and other stringy objects) get so knotted in such a short time? To find out, these physicists started by tumbling strings of different stiffness in a box. They found that "complex knots often form within seconds" (so it's not just my imagination!), and that stiffer strings are less likely to get knotted up. They then used these data and computer simulations to explain how the knots are likely formed (see figure below); basically, when jostled, the strings tend to form coils, and then the loose end weaves through the other strands, much like braiding or weaving. And voila! ...