Francis Tapon, San Francisco asked:
I listened to the Naked Scientists podcast while walking across America, and I have a question about tangling wires - I would put my MP3 player into a pocket, and whenever I pull it out the wires are completely tangled up. In fact, they're so tangled I couldn't have done it on purpose! Why do wires tangle up?
We put this question to Mike Pearson, from Cambridge University's Millennium Mathematics Project.
Isn't it just a result of then being moved around inside your pocket by the action of walking? As you take a step the MP3 player is raised in your pocket, which is a tight enclosed space, and as such the wires moved down. with the next step the opposite happens, so the more you walk, the more tangled the wires become.
Could it have something to do with electromagnetism? (and possibly the close proximity of a mobile phone etc).
I haven't heard the podcast yet.
Just for Kat.
Leave it to physicist's to actually investigate this daily annoyance. Dorian Raymer and Douglas Smith discuss the creation of knots in strings in an article entitled "Spontaneous Knotting of an Agitated String" in the October 16th Proceeding of the National Academy of Sciences. http://www.pnas.org/cgi/content/abstract/104/42/16432 has the abstract available.
Surely during use and winding up and out again of the cables would put some twisting into the cable, and as a result would have tensions in said cables and they work themselves out whilst being moved around in the bag, and we see the result.
I have the same trouble with lunge lines. No matter how carefully I wind them, they always end up knotted. DoctorBeaver, Tue, 12th Feb 2008
Just nature's way of irritating us all. johnnyfr, Tue, 11th Mar 2008
I have a Newton's cradle which I have to transport around on school visits. It drove me mad because I would have to spend 10 minutes of setting up time untangling the thing. Then I discovered that if I fastened a scout waddle on one side it never tangles. I think you should tie up your cables tightly so that they are not lose and able to tangle. Make it Lady, Tue, 11th Mar 2008
I wonder why they don't make small audio cables with a 'lay' like they make ropes. With ropes, you can hank many metres by 'dropping' it, clockwise, over your left hand with your right hand; no twisting force is needed and it uncoils so easily.
"Just nature's way of irritating us all."
The twisted wire knot-look and quick pull release makes this a nice trick for a six year olds birthday party and even if it's not perfect solution for entanglement, it is pretty neat! Phillip1@rogers, Sun, 19th Jun 2011
I realize this is a little old. But, thanks to Phillip, it has been brought back to the top.
With due respect to the mathematicians, who are much smarter than I, I think something else might be going on, besides randomness, and ambient movement, shaking, etc. Particularly with two examples: Those very thin, flexible ear bud leads, and, that great mystery, the 'coil-cable' standard-style telephone handset cables - they don't 'tangle' as such, but become inexplicably wound, twisted - requiring disconnecting and turning many times to untwist. What repeated phone-user behaviors could possibly create all these twists? My theory: The cables are pre-energized,so to speak, because of systematic twists - potential energy - already in the multiple conductors within them, created in the manufacturing process. Perhaps in the boating throw-rope example given, there's little tangling because the the rope is made in a way that doesn't introduce preloaded tensions. Just a guess. Bob Bob Trent, Tue, 8th May 2012
Some of the problem is probably to do with twists, but less when they are made and moe how they are used, coiling puts twist into a cable, but rolling doesn't, so if you roll and then uncoil, or coil and then unroll you will change the number of twists. daveshorts, Tue, 8th May 2012
Thank you Paul.fr? You gave me and all a solution that works great!
Here's a little trivia for you: The human tendency is to try to create order out of chaos. As an example, after you've used an ear bud (earphone) you will generally wrap the cord around and around your fingers before you put it in your pocket. When you pull it out, you will notice that it has tangled and is generally a mess and a lot of trouble to straighten out again. You will actually have less problems if you just bunch it up and then pocket the cord. Go ahead, prove it to yourself next time. Proving it mathematically is a whole 'nother problem **smile** Tom, Mon, 28th Jan 2013