Shoes getting untied are a worldwide phenomenon, and is something that is usually taken for granted. But UC Berkeley mechanical engineers have finally taken interest and conducted a study to find out the real reason why shoelaces or shoestrings unravel. The answer is very interesting and unexpected.
The engineers said there is a double whammy of forces from stomping and whipping that are like invisible hands, Eureka Alert reported. The invisible hands loosen the knots of the laces until they become totally unraveled. This may be a simple example of how science answers obvious question, but this is also important for understanding how knots fail in certain situations.
The engineers used a slow-motion camera to capture how the shoelace failure happens. The images show that the unraveling of the knots happens in a matter of seconds. They found out that the knots fail due to a complex interaction of various forces.
The study was done when EC Berkeley's Dr. Oliver O'Reilly got fed up with how the knots of his shoelaces always get unraveled, ABC 7 reported. This frustration leads to a curiosity that brought them to the intense investigation. He worked with mechanical engineering graduate students Christopher Daily-Diamond and Christine Gregg to accomplish this research.
The topic may be simple, but the elements involved make it more significant. Some of the factors include the fabric of the shoes, the speed of walking, the torsional stiffness, the bending, the material used for the shoelace, and the walking strides. It took the team two years to understand these phenomena, which they call "dynamic untying."
One of the engineers has to walk and run so many miles in the streets and on the treadmill to capture on camera the unraveling of the shoelaces. They found that the untying of the knot is not due to human error, but physics, since they saw that even the strongest knots get unraveled.
