Image: Dorian Raymer, UCSD
Two physicists from University of California, San Diego unraveled the mystery behind how knots form in tangled telephone cords and electronic cables:
Smith and UCSD colleague Dorian Raymer ran a series of homespun experiments in which they dropped a string into a box and tumbled it for 10 seconds (one revolution per second). They repeated the string-dropping more than 3,000 times varying the length and stiffness of the string, box size and tumbling speed.
Digital photos and video of the tumbling strings revealed: Strings shorter than 1.5 feet (.46 meters) didn't form knots; the likelihood of knotting sharply increased as string length went from 1.5 feet to 5 feet (.46 meters to 1.5 meters); and beyond this length, knotting probability leveled off.
Most telephone cords and other wires and computer cables etc. hang from and are stuffed behind desks and couches and are not kept in a moving box.
This article is confusing to me because I consider a knot to be different than a cord bunching up and getting tangled.
A knot has to be undone, whereas a tangle can be pulled apart (like a phone cord).