(Shoe) String Theory -- Scientists Investigate Why Shoelaces Come Untied

Discussion in 'General Science & Technology' started by Yazata, Apr 14, 2017.

  1. Yazata Valued Senior Member

    We've always wondered. They are securely tied one moment, and loose the next. What happened?

    Well, an international team of scientists at UC Berkeley and Aston University in the UK are on the case.

    And no MR, it isn't Gremlins.


    They enlisted volunteers on treadmills and robots that stomped and swung mechanical legs. Neither stomping or swinging by themselves caused the knots to come untied.

    But a combination of stomping and swinging did. Apparently stomping causes the knot to become tied less tightly so that slippage becomes possible in it. The swinging of the leg imparts lateral forces that pull on the laces. After enough of that a catastrophic failure ensues and the knot unravels very rapidly.
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  3. DaveC426913 Valued Senior Member

    Technology improves.

    Shoelaces are obsolete.

    They can have my velcro sneakers when they pry them from my cold, dead feet.
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  5. Xelasnave.1947 Valued Senior Member

    Inspired by Mythbusters?

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  7. iceaura Valued Senior Member

    Most shoelaces that loosen do so because they were tied in a Granny Knot instead of a Square knot. If you tie a square knot and wrap two turns around the standing loop instead of one, all that swinging and stomping will leave your shoes tied as before.

    The Granny is what they are calling the "false knot", in the article.

    Knot people say the reason the Granny comes loose easily is that the free tails are touching each other, run past each other, share a common "hole"so to speak. So the grip loops only touch each one on one side. As they work on each other, they work loose, initially by being jolted so they "squirm" in the catchment.

    But I never tested that - it made sense looking at the knots, but I took the sense for granted. Now I've been scooped.
    Last edited: Apr 14, 2017
  8. Dinosaur Rational Skeptic Valued Senior Member

    I wonder if they got paid for the time spent on this critical project.
  9. DaveC426913 Valued Senior Member

    Everyone always asks that of research like this.
    The science of structural and materials failure keeps people alive.

    I sure hope they pay them. And pay them well.
  10. Write4U Valued Senior Member

    There are college level mathematics on tying shoelaces as well as tying different knots in dress ties.

    p.s. ever looked at a book on sailor's knots? Amazing configurations for very specific purposes.
    Last edited: Apr 25, 2017

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