Imagine this heart-wrenching scenario: You're standing on the 18th green, the match hanging in the balance. You carefully line up your putt, take a deep breath, and send the ball rolling toward the hole. The speed seems perfect, the line looks true—until, in a cruel twist, the ball teeters on the edge, dips in, and then pops back out onto the green. It's a moment every golfer dreads, and it's known as the 'lip out.' But here's where it gets fascinating: new research from the University of Bristol has delved into the physics behind this frustrating phenomenon, revealing insights that might just change how you approach your next putt.
The lip out is a peculiar quirk of golf that doesn’t discriminate—it haunts both weekend warriors and seasoned pros alike. It occurs when the ball strikes the edge (or 'lip') of the hole but fails to drop in, instead rolling away as if mocking your efforts. To unravel this mystery, Emeritus Professor John Hogan from the School of Engineering Mathematics and Technology at the University of Bristol applied his expertise in mechanics to the problem. His findings were published in Royal Society Open Science, shedding light on the forces at play during these agonizing moments.
Professor Hogan has humorously dubbed these unpredictable golf balls 'the golf balls of death,' drawing a parallel to the daring 'wall of death' stunt performed by motorcycle riders. And this is the part most people miss: it’s not just about bad luck—there’s precise science behind why the ball behaves this way.
"We analyzed the motion from a mechanical perspective," Professor Hogan explained. "Our research demonstrates that there are two distinct types of lip outs: the rim lip out, where the ball’s center of mass never dips below the level of the green, and the hole lip out, where it does."
At the core of both scenarios lies a concept called 'degenerate saddle equilibria'—a fancy term for the precarious moment when the ball is balanced on the hole’s rim. It’s neither falling in nor resting safely on the green; it’s right on the edge, quite literally. In a rim lip out, the ball skims around the top of the hole at a fixed angle and speed, and even the slightest disturbance—a grain of sand, a gust of wind, or a tiny spin—can determine whether it drops in or rolls away.
The hole lip out, on the other hand, is far less common and occurs under specific conditions. As Professor Hogan explains, "In this case, the ball falls into the hole and undergoes a pendulum-like motion as it rolls around the inner wall. Its potential energy is converted into spin, and if it doesn’t touch the bottom of the hole, it can bounce back up to the rim and roll out onto the green again."
But here's where it gets controversial: How much control do golfers really have over preventing lip outs? Professor Hogan’s advice is straightforward yet challenging to execute. "My golfing friends often say lip outs happen when you hit the ball too hard," he notes. "Our research shows that the key is to aim as close to the center of the hole as possible and approach the rim with minimal speed. That way, the ball’s momentum is just enough to tip it into the hole, without carrying it around the rim and back out."
Professor Hogan’s work is rooted in the study of mechanics—the science of how objects move under the influence of forces. Sir Isaac Newton used these principles to understand planetary motion, and now they’re being applied to the intricacies of sports. This research builds on Professor Hogan’s previous explorations into the physics of skateboarding and the motion of a basketball after it hits the rim, showcasing the broad applications of mechanics in everyday scenarios.
So, the next time you find yourself facing a crucial putt, remember: it’s not just about feel and finesse—it’s about physics. But here’s the question: Do you think golfers can truly master the science behind the lip out, or is it just another unpredictable element of the game? Let us know your thoughts in the comments below!
More information: Mechanics of the golf lip out, Royal Society Open Science (2025). DOI: 10.1098/rsos.250907. royalsocietypublishing.org/doi/10.1098/rsos.250907
Citation: Golf's cruelest moment: The physics behind the 'lip out' phenomenon (2025, November 4) retrieved 4 November 2025 from https://phys.org/news/2025-11-golf-cruelest-moment-physics-lip.html
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