Why Do Shoelaces Come Untied?

Something bothered Oliver O’Reilly.  Specifically, he was bothered that his shoelaces always came untied when he went out running.  O’Reilly, a professor of mechanical engineering with the University of California, Berkeley, decided to conduct an in-depth study to figure out why his shoelaces came untied when he went running.

Using a high-speed camera and a study co-author (Christine Gregg) as the runner, they filmed actual knots untying.  Eventually, the researchers conducted studies on a pendulum that mimicked the stride of a runner.  This kind of controlled study (pun intended) added weight to their work.

Okay, I am going to tell you what the researchers discovered.  Try to keep up with me on this part.  I will put this in plain English to help.  Here is what the researchers figured out: Shoelaces come untied because the laces are flopping around.

Holy wow!

Who knew?

Upon finishing their study, the researchers published a paper.  The paper includes actual photographs of shoelaces, some stuff about inertia and gravity, and shoes.

I read about this study with great fascination, but in the end wondered: Why didn’t Oliver’s mother teach him to tie a double-knot so his laces won’t come untied?

--Mitchell Hegman

If you are interested in reading more about the shoelace study, try this link: http://www.livescience.com/58649-why-shoelaces-untie.html