HONOLULU (HawaiiNewsNow) - Why do shoelaces come untied? Berkeley scientists studied this. They unraveled the issue of shoelace knot failure.
The force of a foot striking the ground stretches, then relaxes the knot. The motion of the leg moves the ends of the laces like an invisible hand. Gradually these forces loosen the knot you tied.
The researchers studied the slow motion video. and they diagrammed the reactive forces. So, why bother? According to them, an understanding of shoelaces could be applied to other lace-like structures, like DNA.