How does a well-knotted shoelace come untied on its own? Seems like everyday I'm retying my shoes.
2007-10-23 14:51:04 · 8 answers · asked by whitesox09 7 in Science & Mathematics ➔ Physics
As others have said, as you walk and move around the knot tends to loosen. Which is not a bad thing if it only loosens enough so that it's easy to undo at the end of the day, but when you have to tie your shoes in double knots two or three times a day it gets frustrating - that's what I had to do with my last pair of shoes.
Obviously a lot depends on the material the shoelaces are made from / coated with. Ideally you want them to be rough enough that the friction is enough to stop the knot undoing on its own. So if you're having problems with this, I'd suggest buying some different shoelaces and seeing if that helps. Try to get some that feel a bit rougher.
2007-10-23 15:56:47 · answer #1 · answered by Scarlet Manuka 7 · 1⤊ 0⤋
It depends a lot on what material the shoe laces are made of. And their shape. If you have the hard, round, shiny black shoe laces for dress shoes, they come untied pretty easy. They have a round, unyielding shape and are a little slippery. The flat, usually white shoe laces in tennis shoes stay tied much better. This is because of their shape, the less slippery material they are made of, and the fact that their shape deforms more easily when they are tied.
You said you are retying your shoes everyday. If you only have to retie them once a day I wouldn't worry about it.
2007-10-24 22:05:30 · answer #2 · answered by Northstar 7 · 0⤊ 0⤋
Seems like shoelaces have been made of really slippery material as of late. Maybe it's cheaper to make them, or keep them cleaner. In any case, it's annoying. I agree. Getting new shoelaces on a pair of $60 sneakers is not my idea of accessorizing.
In my childhood, you tied them once, and they only came undone when I pulled on both ends of the lace. You know, like it's supposed to function.
Anyway, good luck mate.
2014-01-13 12:24:01 · answer #3 · answered by George 1 · 0⤊ 0⤋
Usually one at a time.
The shoelaces are held in a nut by friction. Tighter means more normal force around the nut and therefore more friction(stronger grip). As you walk an impulse is being supplied I=Ft jerking the nut a bit by bit loosening it.
I recommended dabbing a bit of strong glue on the nut or switching to Velcro... :-)
2007-10-23 15:29:23 · answer #4 · answered by Edward 7 · 0⤊ 0⤋
If your shoelaces are coming untied often, it may be because the knot you are tying is uneven. A symmetrical knot will be more stable than one that is not.
2007-10-23 15:27:43 · answer #5 · answered by Lynda 2 · 1⤊ 0⤋
With nylon or cloth shoe laces, most common on tennis shoes, oils from your fingers accumulate over time (from tying and un-tying), thus reducing the friction capacity of the laces. Hense, the older the laces, the more oil they have in them, and the greater the propensity to become untied.
2013-11-15 11:47:32 · answer #6 · answered by Paul 2 · 0⤊ 0⤋
As u walk,it tends to get loosen every ones and a time
2015-02-15 17:19:16 · answer #7 · answered by mia 1 · 0⤊ 0⤋
As you walk, you're gradually 'shaking' it loose every time you lift your foot and take a step.
2007-10-23 15:13:14 · answer #8 · answered by lollerskates 2 · 1⤊ 0⤋