The surprising new physics of squeaky basketball shoes

"We were not expecting to find so much richness and depth from a physics point of view underneath the sole of a shoe, says Adel Djellouli, a scientist at Harvard University and co-lead of the study. In a new study, scientists explore the physics that give rise to the familiar squeak of basketball shoes sliding on a hard surface."

"Most scientists who had considered the problem believed that shoe squeaks were a straightforward example of the common stick-slip phenomenon. When a player stops on a dime, their shoe's rubbery sole slips slightly in the same stop-and-start pattern, just many times a second, producing a squeak. This is how violins work, and why a squeaky door hinge rings a lower pitch when you open it slowly."

Basketball season brings the familiar sound of squeaking sneakers on hardwood courts. Researchers at Harvard University conducted a study published in Nature to understand the physics behind these iconic sounds. Previously, scientists attributed shoe squeaks to simple stick-slip friction, the same phenomenon that causes jerky motion when sliding objects or produces violin sounds. However, using high-speed cameras and acoustic analysis, researchers discovered unexpected complexity in the physics underlying basketball shoe squeaks. The study reveals that the interaction between shoe soles and court surfaces involves richer physical mechanisms than the straightforward stick-slip model suggested, advancing scientific understanding of this everyday phenomenon.

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