What a tangled mess!

If you've ever called me on the phone here at the Gazette, you might have heard a lot of clatter and curses just before I answered your call.

That's the sound of me trying to shake the phone cord loose from the rat's nest it has formed with the headphone, tape recorder and other cables on my desk. No matter what I do, the cords always seem to tangle themselves together within seconds, writhing about like snakes in a techno-hibernaculum.

It's the same with extension cords, ropes and hoses. I wrap them as carefully as I can, but the instant I turn my back on them, blammo! Instant tangle.

It's physics

While I initially suspected that this phenomenon was some sort of expression of quantum entanglement or universal entropy, I've since learned that it actually comes down to simple physics.

Douglas Smith, a professor of physics at the University of California, San Diego, did a now-Internet-famous study of spontaneous knotting in an agitated string back in 2007.

Smith says that he and co-author Dorian Raymer got the idea to do this study when Raymer was studying knot theory (the mathematical theory of knots) and Smith challenged him to find a practical use for it.

Smith and Raymer decided to study how knots formed in string by putting a piece of string into a clear plastic box and spinning it to see if it knotted, varying string length and type, rotation speed and time and box size as they did.

Exactly 3,415 trials later, they concluded that the odds of a string knotting spontaneously approached 100 per cent as your string length, flexibility and agitation time increased.

"This is a Murphy's Law thing," Smith says in an interview – any amount of agitation in a string, cord or rope applied for enough time will cause it to knot and tangle.

Imagine a simplified model where you take a string and coil it, Smith explains. If we assume that each coil can only move in two directions, each coil has a 50 per cent chance of crossing over or under one of its neighbours whilst under agitation. If a coil crosses over and under one of its neighbours enough times, you get a knot.

"The computer simulation we did of this shows that if you just keep doing that, even though it's random, it will tend to produce knots," Smith says.

But this doesn't happen in the absence of an external force, Smith notes. If a cord tangles, it's because it's moved – possibly when you picked up the phone.

"People think it's just magic," he says.

"That's not true. It has to have moved."

(Smith and Raymer won an Ig Noble award for this study in 2008. The Ig Noble Awards honour scientific achievements that make people laugh and think.)

It's also mechanics

Manufacturing is another factor, says Rob Ludwig, owner of Cancord Inc. (one of Canada's biggest rope-makers).

Ropes, strings and cords are made by twisting many small fibres together, Ludwig explains. A well-made rope will have half the fibres twisted one way and half the other, so that the rope itself has neutral twist and no net force on it. Badly made ones won't, and will have a net force that pushes/twists them in one direction. As noted by Smith, force means motion, and motion means knots.

You can also impart twist to a rope by leaving it curled up for awhile, Ludwig continues. That biases the orientation/memory of the fibres, making them more prone to curl or tangle.

"If you were to rotate your phone every time you hung it up, over time it's going to have a bit of a twist in it," he notes.

Headphone, phone cords and other thin cords are particularly prone to this as all the wires in them are twisted just one way, notes Darren Bain of Edmonton's CND Rope – it's too expensive to twist them like rope.

Smith says you can reduce your odds of tangles by using a stiffer string. Apple has patented a way of stiffening parts of iPod headphone cords for this purpose.

Thicker cords and ropes work too, Bain says. Some charger cables have thick fabric covers on them for this reason.

It's best to avoid twisting in the first place, Ludwig says. Don't leave your cords and ropes coiled for long, and straighten them out on occasion. If you must coil them, use a reel to avoid imparting a twist.

Maybe I should just get a cordless?