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Phoenix666 [soylentnews.org] writes:

Got rope? Then try this experiment: Cross both ends, left over right, then bring the left end under and out, as if tying a pair of shoelaces. If you repeat this sequence, you get what's called a "granny" knot. If, instead, you cross both ends again, this time right over left, you've created a sturdier "reef" knot.

The configuration, or "topology," of a knot determines its stiffness. For example, a granny knot is much easier to undo, as its configuration of twists creates weaker forces within the knot, compared with a reef knot. For centuries, sailors have observed such distinctions, choosing certain knots over others to secure vessels -- largely by intuition and tradition.

Now researchers at MIT and Pierre et Marie Curie University in Paris have analyzed the mechanical forces underpinning simple knots, and come up with a theory [sciencedaily.com] that describes how a knot's topology determines its mechanical forces.
...
"This theory helps us predict the mechanical response of knots of different topologies," Reis says. "We're describing the force it requires to close a loop, which is an indicator of the stiffness of the knot. This might help us to understand something as simple as how your headphones get tangled, and how to better tie your shoes, to how the configuration of knots can help in surgical procedures."

The article has a nice description of their approach.

Original Submission