How To Keep Laces From Untying

The laces on the left are tied in a strong knot that lies horizontally. The laces on the correct are tied in a knot that makes the bow lie vertically and which, co-ordinate to new enquiry, can come untied more easily. Meredith Rizzo/NPR hibernate explanation

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Meredith Rizzo/NPR

The laces on the left are tied in a strong knot that lies horizontally. The laces on the right are tied in a knot that makes the bow lie vertically and which, according to new research, can come up untied more easily.

Meredith Rizzo/NPR

For more than than xl years, Oliver O'Reilly'southward shoelaces take been coming untied pretty much every day. And for most of those 40 years O'Reilly didn't think too much most information technology.

Merely then, virtually a decade ago, his girl Anna was learning to tie her shoes, and O'Reilly decided his shoelace trouble wasn't worth passing on to some other generation.

"I didn't desire her to inherit my problems, so I went online and found some actually helpful videos to teach me how to tie her shoelaces," he says.

Peradventure if O'Reilly had had a different chore, that's where the shoelace problem would have stopped. But Oliver O'Reilly is a professor of mechanical engineering science at the University of California, Berkeley, and as he looked at videos of shoelace knots, he started wondering why they came untied in day-to-24-hour interval life.

"That problem always stuck in my listen," he says.

Now, he and two graduate students accept published a paper, in Proceedings Of The Royal Social club A, titled "The roles of impact and inertia in the failure of a shoelace knot."

To written report how shoelaces untie themselves, the team did a handful of experiments. "We did all sorts of stuff," says graduate student and co-author Christine Gregg. "Nosotros ran on treadmills. We swung our legs back and along while sitting on tables, to take the touch out of the equation. Nosotros only stomped our feet like Frankenstein."

In all, they estimate information technology was well over 100 hours of testing, over virtually two years.

"We were wandering the halls of the mechanical engineering edifice just staring at our shoes, watching them come untied," Gregg says.

Gregg's anxiety are featured in this slow-move video the team shot at the campus gym.

YouTube

Chris Daily-Diamond, the third co-author, shot the video and did a lot of the legwork (pun intended) on the experiments.

Based on the video, and the other tests they did on shoelace knots, the squad says two things happen when a lace comes untied. Offset, the impact of the shoe on the basis loosens the knot. With the knot loosened, the whipping of the free ends of the laces — as the leg swings back and forth — makes the laces slip.

Equally the human foot hits the ground and the laces swing repeatedly, the knot loses integrity until, in a matter of seconds, information technology fails altogether.

The researchers as well take some communication to keep shoes from coming untied. Information technology'south all in how you necktie the knot.

Basically, there are two similar ways to necktie your shoelaces in a bow. The knots await almost identical, only 1 is significantly stronger than the other. Here's a diagram the researchers fabricated of how the knots differ.

The easiest way to tell if you're tying a strong bow or a weak ane is by looking at how the finished bow naturally lies on your shoe. If it lies across the shoe, perpendicular to your foot, it's the stronger knot. If it lies down the top of your shoe, parallel to your human foot, information technology'due south the weaker knot.

If you detect (as all 3 researchers and I did) that you lot are habitually tying the weaker version on your own shoes, Gregg says there is a theoretically unproblematic way to prepare it.

"Just go the other way around your loop when you're tying the last function of the [bow]," she explains, although years of muscle memory tin make this easier said than done.

Gregg has been the most successful at transitioning to the strong knot in daily life, says Daily-Diamond. "Oliver and I are yet in rehab."

In the paper, the researchers also reference this pop 2005 TED talk past Terry Moore about how to tie your shoes amend.

Daily-Diamond says there nevertheless is a lot of work to be done, across the shoelace example, about how tangles or knots come untied in dynamic situations. And the scientists say an unnamed shoe visitor has already approached them about their work, as well.

Source: https://www.npr.org/sections/health-shots/2017/04/17/523636317/untangling-the-mystery-of-why-shoelaces-come-untied