Research reveals how to stop cables knotting

Knotted Cables

2 July 2014

The long-held belief that string ‘spontaneously’ knots has now been confirmed by research which also found that joining the ends of string together dramatically reduces the chance of this happening.   

The study, led by Robert Matthews, Visiting Reader in Science at Aston University, sheds light on the common phenomenon of headphones cables tangling, and shows how to prevent this without the need for additional gadgets like cable tidies. 

Robert set out to investigate what he calls the ‘Murphy's Law of String’ – that is, ‘if string can get into knots, it will do’. Building on earlier mathematical research, he concluded that:

•        String really does have a perverse tendency to knot spontaneously

•        The longer the string is, the more likely it is to spontaneously knot

•        Joining the ends together dramatically reduces the probability of the string performing the manoeuvres needed to form knots, making tangling less likely, something he calls the Loop Conjecture 

To test the Loop Conjecture, he asked schools nationwide to conduct experiments, jumbling up regular parcel string varying lengths and then repeating this process with each string having its ends joined, forming a loop. Schools nationwide participated, with Coundon Court near Coventry performing 12,000 individual knotting tests. The results of the experiments confirmed the Loop Conjecture, proving that simply joining the ends of your headphone cable together can dramatically cut the chance of it knotting. 

Robert Matthews said: “The study explains why your headphone cable mysteriously turns into one big jumbled mess while it’s in your bag or pocket. We’ve also struck upon an easy solution – simply clipping together the two ends of the cords makes the cable less likely to form a knot – saving the frustration of having to untangle it before plugging in. 

“This was all about using hard science to tackle an everyday issue. It was great to see how enthusiastic school students were to get to grips with the surprisingly complex science behind the phenomenon, and carry out experiments to study the effect and identify the solution.”

The phenomenon of spontaneous knotting has other real-world implications. It has attracted interest from biochemists working on DNA, as this thread-like molecule also gets itself tangled, with potentially serious consequences. The new findings in Robert Matthews’ paper suggest that nature may sometimes form loops in DNA to reduce this risk. 

Robert Matthews added: “This was a fun piece of research that has an immediate application that everyone can benefit from, but any implication our findings have on the fight to solve major health challenges will be even more important.“ 


Contact details 

For further information, to interview Robert Matthews, or to pursue a broadcast opportunity with Coundon Court school, please contact Madeleine Crowther:E:

Study information

-          The full paper has been accepted for publication in the peer-reviewed journal School Science Review.

-          Methodology: Various lengths of ordinary parcel string were jumbled by hand 20 times to give a reasonable number of data-points by which to gauge the proportion of knot-free jumblings, which becomes an estimate of the probability on a knot-free state for a specific length of string. This was then repeated for at least half a dozen different lengths of string to give enough data-points. The procedure was then repeated, but with each length of string having its ends joined, forming a loop. The experiment was conducted in collaboration with the Department of Mathematics at Aston University. They issued a call for participation to UK schools via STEMNET. This resulted in around a dozen schools expressing interest and requests for an information pack to conduct the experiments. 

Notes to editors

-          Robert Matthews has made an extensive study of the history and scientific basis of urban myths, such as Murphy's Law.

-          The School of Engineering and Applied Science:  The School’s focus is on the inter-disciplinary nature of engineering and applied sciences, the key technologies and their interactions. The School is organised into Academic Groups that bring together staff and students around cognate disciplines within engineering and applied science, for adminstrative and intellectual purposes: Chemical Engineering & Applied Chemistry, Computer Science, Electrical, Electronic and Power Engineering, Engineering Systems & Management, Mathematics and Mechanical Engineering & Design. For more information visit:

-          Aston University: Founded in 1895 and a University since 1966, Aston is a long established research-led University known for its world-class teaching quality and strong links to industry, government and commerce. Professor Dame Julia King became Vice-Chancellor of the University in 2006. Aston has been a leading university for graduate employment success for over 25 years. The University is currently ranked 8th overall for graduate employment in the 2013 Sunday Times University Guide. The School of Engineering & Applied Science, with its tradition of quality and reputation for cutting edge research, offers students excellent opportunities to join in the process of discovery and creativity, and prepare for an increasingly diverse and technological world.