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.
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).
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.