You get off the subway, stash your earbuds in your pocket, and when you pull them out again, they're completely tangled—even after you painstakingly untangled them yesterday. Why does it happen every time? Well, there's actually a whole branch of science to help explain, and it's called knot theory, Wired reports. A 2007 experiment conducted at the University of California, San Diego, may shed some light on the situation.
Researchers dropped string into a motorized spinning box, examining the resulting knots. They argued that knots occurred because when a string is coiled in order to fit in a small space, its end is parallel to other sections. Spinning makes it possible for that end to loop around a segment, and more spinning means more looping. In half of the 10-second spins, strings came out knotted. The longer a string was, the higher the chance of knotting—up to a point. Strings shorter than a foot-and-a-half didn't usually get knotted, and those beyond five feet long got knotty just half the time. So how to avoid knots? Stiffer cables help reduce tangling, as do smaller spaces. Or you can try a do-it-yourself method to avoid tangling.