Scientific study on why knots happen

Danny says: Tangled telephone cords and electronic cables that come to resemble bird nests can frazzle even the most stoic person. Now researchers have unraveled the mystery behind how such knots form."
200710041236 [Douglas Smith of the University of California, San Diego] 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.

Their conclusion?
While there is no magical knot buster, Smith advised what all sailors, cowboys, electricians, sewers and knitters know: to avoid tangles, keep a cord or string tied in a coil so it can't move.


  1. So, how do they explain stuff bags?

    Climbers, whose lives depend on knot-free ropes, simply stuff their ropes into open bags.

    I’m going to guess that this only works if the maximum length of a stuff bag loop (the longest a loop can be inside the bag) is less than the 1.5 m limit. But it’s just a guess.

    And, what’s with an absolute limit? This article suggests that dental floss and the ropes used to moor a frigate have the same “knot-free limit length”.


  2. “Another pointless science experiment. Well done people.”

    No trully scientific experiment is pointless. Rmemenber, even the Darwin awards winners have made their contribution to evolution :P

  3. What have we learned?
    You have to study maths to achieve this great conclusion.
    I expected they provide us with a quicker way to unknot. Since those knots form after a short time (like 10 sec), the process of undoing should be similar fast. I bet we all unknot according some wrong pattern: Starting with one end and work through the chaos. But those knots don’t develop that neat way, so to undo them you’d need work the same way backwards. Maybe looking carefully at the pattern before starting and trying to figure it out, could make a faster knot-solvers- I think that’s portable to all other kinds of problems: Don’t just start mechanically and the good old way you’ve learned it, but take the blinkers off and try an alternative creative and personal way.

  4. How come my shoe laces can knot themselves when I’m trying to loosen ’em up and they’re only 9-1/2″ long? Hmm?

  5. Not having read TFA, I’m surprised that the
    conclusions would be so general about what length
    tends to form knots.

    I’d think the size of the box, shape of the box,
    stiffness of the rope, roughness of the rope, etc.
    would play a role somehow.

  6. It seems that this may have applications in engineering vehicles where tethers are involved. Seems very useful to me.

  7. any stagehand/techie who had to deal with cable ( audio, video electric) knows the coil trick. DOH

  8. Come on people, this is some seriously cutting-edge stuff. How can you possibly be mocking such an important contribution to string theory?

    I mean heck, if we throw a cat in the box with all those strings, we might even be on our way to a grand unified theory…

  9. #1’s got it. The throw lines and climbing lines arborists use rarely knot ot tangle in stuff sacks, all the pros use them. In WWII there were specialists who untangled parachute cords. All tangled coils are made of loops, by making the loops equal sized the tangle falls apart easily. Personal fav is the twist free, kink free, figure-8 coil for air/water hoses and anchor rodes.

    Best story of all was Alexander the Great and the Gordian Knot. He used a sharp sword.

  10. Gordon, I don’t believe that this experiment is useless. Just cause you can’t see the use means nothing.It just means YOU can’t see the use.

    About stuffing ropes into bags, one conclusion was that knots were more likely to form in large boxes than in small boxes so in a small area like a bag, that’s probably why there aren’t knots.

    Gordon, using lateral thinking, I can see how this could be useful right away. Maybe the experiment could be used for traffic.
    If you consider long lines of cars to be strings ,and knots to be jams, and highways to be boxes, it could explain why paradoxically the more highways, the more traffic there is. Hmm. Interesting.
    See, that’s what science does,you never know where you could end up.

  11. The whole point of the scientific method is that one can make an experiment and find nothing. Yet have it all documented so meticulously, that a more enlightened member of maybe a later age may draw conclusions from it.

  12. I would say fake. Either they exchanged the tangled one against an untangled cord (numerous opportunities) or it wasn’t as tangled as it looked in the first place.

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