Shoe-string theory: Science shows why shoelaces come untied

[mahatmakanejeeves]

Last edited Wed Apr 12, 2017, 12:55 PM - Edit history (1)

Yes, these are engineers and not scientists. You'll do just fine anyway.

Shoe-string theory: Science shows why shoelaces come untied
April 11, 2017

Shoe-string theory: Science shows why shoelaces come untied
Credit: University of California - Berkeley

A new study by mechanical engineers at UC Berkeley finally shows why your shoelaces may keep coming untied. It's a question that everyone asks, often after stopping to retie their shoes, yet one that nobody had investigated until now. The answer, the study suggests, is that a double whammy of stomping and whipping forces acts like an invisible hand, loosening the knot and then tugging on the free ends of your laces until the whole thing unravels.

The study is more than an example of science answering a seemingly obvious question. A better understanding of knot mechanics is needed for sharper insight into how knotted structures fail under a variety of forces. Using a slow-motion camera and a series of experiments, the study shows that shoelace knot failure happens in a matter of seconds, triggered by a complex interaction of forces.

"When you talk about knotted structures, if you can start to understand the shoelace, then you can apply it to other things, like DNA or microstructures, that fail under dynamic forces," said Christopher Daily-Diamond, study co-author and a graduate student at Berkeley. "This is the first step toward understanding why certain knots are better than others, which no one has really done."

[voteearlyvoteoften]

1. Flat laces stay tied Round laces are ridiculous

Learned from kindergarten teacher

[Warpy]

2. I found the secret to keeping those tied

Instead of the once under primary knot, do a twice under. Then tie the bow. Then pull the loops out so they're a lot longer than the ends and do a once-under knot with them. That sort of thing would last through 12 hours of running cement floored halls during nursing shifts. Untying was no problem, just undo the simple knot holding the loops, pull the ends and loosen the simple knot at the bottom.

[PoindexterOglethorpe]

3. That's what I do, if I'm reading your description correctly.

Although the way I do it, you can undo the bow the regular way, by pulling on the ends.

I was taught that when very young, and taught my own kids. It's foolproof.

[Warpy]

4. The Russian knot on the bottom works for normal use

Tying the loops on top was necessary for nursing shifts.

[PoindexterOglethorpe]

5. I've done it both ways,

and they both work equally well. I do prefer the one that's easier to untie.

[mahatmakanejeeves]

6. Another link

Nature

Physics

Unravelling Why Shoelace Knots Fail

A better understanding of this pedestrian problem could lead to improved surgeons’ knots and fibers

By Erin Ross, Nature magazine on April 12, 2017

....
This article is reproduced with permission and was first published on April 12, 2017.

[Jim__]

7. Professor Shoelace: How to tie your shoes.

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