(Roughly) Daily

… so, TKSST (The Kids Should See This), advises, we should got to the video…

In 2017, mechanical engineers at UC Berkeley decided to test why our shoelaces sometimes untie themselves while we’re wearing our shoes.

The answer, they learned, is that whether you tie the common shoelace bow tie knot with the stronger reef knot or the weaker “granny” knot, it’s subject to “catastrophic failure” in two stages: impact and inertia.

From astrophysicist Josie Peters in this BBC Ideas video:

“They filmed a runner on a treadmill in slow motion, and used a mechanical pendulum to recreate the forces acting on a shoelace’s knot. And it turns out, every step you take, basically, is trying to untie your shoes.”

“When your foot hits the ground, the impact stretches and loosens the knot. At the same time, as your leg swings, the loose ends of the laces whip backwards and forwards, until, eventually, one starts slipping through the knot.”

How do aglets help or hurt your knots? What’s one of the oldest surviving shoes? How was Velcro invented? And what are some of the other ways you can tie your shoelaces? Peters reviews the history and physics of shoe and knot design in the 5-minute video…

“Why do your shoelaces keep coming untied?” from @tksst.bsky.social.

* Don Norman

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As we lace up, we might recall that it was on this date in 1940 that the U.S, military introduced the four-wheel drive reconnaissance car that we know as the Jeep. In World War II, Jeeps were used by every service of the U.S. military. An average of 145 were supplied to every Army infantry regiment. Jeeps were used for many purposes beyond the obvious, including cable laying, sawmilling, as firefighting pumpers, field ambulances, tractors, and, with suitable wheels, would run on railway tracks.

Jeeps were immediately impactful on military footwear: they required durable, specialized footwear for their drivers and crews– so spurred innovations in military boots, rubber-soled shoes (and protective gear) to meet the demands of rugged terrain and combat conditions. Alas, they did nothing to address the issue of lace tying.