That's the Way the Spaghetti Crumbles: Physicists Solve a Vexing Kitchen Puzzle
Weiss, Peter, Science News
Great scientists sometimes do silly experiments. The renowned physicist and Nobel prize winner Richard P. Feynman, for instance, once got it into his head to figure out why uncooked spaghetti doesn't snap neatly in two when you bend it far enough to break. Pay attention next time, and you'll notice that the pasta tends to shatter into three or more fragments of unequal lengths.
In the midst of making a spaghetti dinner for themselves one night about 20 years ago, Feynman and a friend--supercomputing innovator W. Daniel Hillis--launched into a brief investigation of this perplexing breaking-pasta performance. "We ended up, at the end of a couple of hours, with broken spaghetti all over the kitchen and no real good theory about why spaghetti breaks in three," Hillis recalls, as quoted in the book No Ordinary Genius by Christopher Sykes (1994, W.W. Norton).
Sometimes, such experiments turn out to be not so silly after all. Recently, French scientists who unwittingly followed in the footsteps of Hillis and Feynman, who died in 1988, finally solved the spaghetti mystery. And a group of physicists and mathematicians conducted a related study that transcends spaghetti. The team examined various kinds of brittle rods under circumstances quite different from ordinary bending.
Besides explaining a quirk of everyday life, the new studies are improving scientists' grasp of fragmentation--the process by which objects shatter. "Fragmentation is a complicated problem that we still don't understand very well," says mechanical engineer and materials scientist Kaliat T. Ramesh of Johns Hopkins University in Baltimore. "Most of us are trying to understand the basic mechanisms involved."
Because spaghetti rods are similar in some ways to a wide variety of brittle objects ranging from industrial cutting tools to body armor, the research may end up elucidating how such structures can fracture and fail. "If we understand how things break, we can build tougher structures,' says mathematician Andrew L. Belmonte of Pennsylvania State University in State College.
SHATTERED SCIENCE Fragmentation occurs in nature on many scales, from subatomic-particle collisions to volcanic explosions to the pummeling of planets by asteroids and comets. Disintegration processes are also an important part of the human realm--for instance, the smashing of windows, the pulverizing of ore, and the deadly detonations of bombs, as well as the benign breaking of spaghetti.
The unexpected incomprehensibility of that last example especially perturbs scientists trying to figure out how all this breakage unfolds.
"This is really the kind of simple question that you can't help thinking about over and over until you find the answer," says Sebastien Neukirch of the University of Paris VI, one of the physicists whose new work seems finally to set the bent-spaghetti issue to rest. To illustrate his point, he notes that Feynman isn't the only Nobel laureate to have been captivated by the pasta puzzle. In interviews on French television 14 years ago, after receiving the Nobel Prize in Physics, popular physicist Pierre-Gilles de Gennes of the College of France in Paris repeatedly alluded to the spaghetti mystery as one of the very simple, yet unsolved, problems of science.
Belmonte says that he fell under spaghetti's spell all on his own. An applied mathematician who specializes in fluids and turbulence (SN: 10/31/98, p. 285), he started experimenting with spaghetti and other types of rods early last year.
Because he was collaborating with some colleagues who had an interest in fragmentation, says Belmonte, "I was inspired to think about breaking things. I actually spent some time one evening breaking spaghetti in my sink because I had always been puzzled by that small piece which tries out of me center."
Belmonte knew of some fragmentation experiments performed in the early 1990s. The researchers had put glass rods inside sturdy steel cases and then dropped those packages onto concrete floors from varying heights. …