National Public Radio has a segment called “On Your Health.” And believe it or not this morning it was on why your shoe laces come untied. (Is this a health problem?) A professor was wondering about this phenomena and had three graduate students study the problem.
The long and short of it is that walking flings the ends of the laces outward and loosens the knot. Further walking causes the knot to spontaneously come undone but this occurs much more often if the knot does not lay flat against the shoe when the knot is not perpendicular to the shoe. Please see the picture below and for details – please go to the link below:
The importance of this? Well it turns out such complex things like DNA molecules may be folded in similar ways as our shoelaces. Understanding how shoelaces unravel may help us to understand some of the fundamental ways that DNA molecules function. It never fails to amaze me how some simple things can help us understand very complex things!
The knot on the left is twice as strong as the knot on the right!