Comparing friction in cotton and synthetic laces

The math of shoelaces

Chapter 1

The basic anatomy of a shoelace knot

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Answer

Chapter 2

The topology of mathematical knots

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Answer

Chapter 3

The lacing grid optimization

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Answer

Chapter 4

The physics of the walking impact

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Answer

YOUR GOAL

Master of The math of shoelaces

Ch 4 · The physics of the walking impact

Knot Escape* - A bit long.
* *Slip 'n' Knot* - Sounds

BETA

dash Drag and loop the laces to discover the surprising math that keeps them tied.

dash Shoelace physics

Stomping seven G's / whipping ends fly / knots unravel fast

dash How swinging lace ends act like whips

How swinging lace ends act like whips

dash Swinging lace ends act like whips, pulling loops open.

The double whammy force of human walking

dash Foot strikes and swinging legs combine to unravel knots.

Fun Fact

Space shoelaces: Astronauts in microgravity don't experience foot strikes, so their shoelaces rarely come untied from walking forces.

Glossary

inertia (noun)
The tendency of matter to remain at rest or continue in motion unless acted upon by an external force. In 2017, Berkeley scientists found that leg swings generate inertial forces that pull loosened shoelaces apart.

Gossip

Do you prefer round or flat laces?

Quiz

Which combination of movements is required to make a shoelace knot fail while walking?

dash The double whammy force of human walking

Gossip

Have you had an embarrassing untied moment?

Quiz

Why do flat cotton shoelaces stay tied longer than round polyester laces?

dash Filming untying shoelaces with high speed cameras

Quiz

What force does a foot strike exert on a shoelace knot while walking?

dash Comparing friction in cotton and synthetic laces

Quiz

What did the UC Berkeley researchers use to test shoelace knots under controlled forces?

Quiz

What happens to the friction inside a shoelace knot just before it completely unties?

Quiz

Which university conducted the 2017 high-speed camera study on why shoelaces untie?

Quiz

How do the swinging ends of your shoelaces contribute to untying the knot?

Quiz

What is the term for the sudden, rapid untying of a shoelace after long periods of walking?