Why Shoelaces Become Untied: Berkeley Researchers Figure It Out

BERKELEY, CA – A new scientific study by engineers at the University of California at Berkeley shows why shoelaces come untied, according to university officials.

The study was published Tuesday in the "Proceedings of the Royal Society A," a physical sciences research journal.

Researchers said no one has investigated what many people wonder about and the study extends research into how knots and other knotted structures fail.

The study suggests that a combination of stomping and whipping forces loosen the knot and tug on the free ends of the laces until the knot comes undone, university officials said.

A series of experiments and a slow-motion camera was used to show that the knot fails in a matter of seconds. A complex interaction of forces triggers the failure.

Berkeley graduate student Christopher Daily-Diamond, who co-authored the study, said if researchers can understand the shoelace, then they can apply that to other things such as DNA or microstructures that fail
under changing forces.

Researchers said there are two ways to tie a shoelace knot. One is stronger than the other. The strong version involves the square knot. The other involves a false knot.

Either knot will fail in the same way, according to the study, but it will take longer for the strong knot to fail.

Still, the researchers don't understand why there is a fundamental mechanical difference between the two knots.

The goal of the study was to provide a basic understanding of how the shoelace bow tie comes undone under changing forces.

Earlier studies have shown how knots and other knotted structures fail under sustained loads, while few studies have looked at how knots and knotted structures fail under changing forces and loads.

• ALSO SEE: How Long Are Hard-Boiled Easter Eggs Safe To Eat?

--Bay City News/Morguefile image