Try it out – Hold a dry spaghetti noodle on both ends and bent it. It will bend and break from the middle, not into two but three to four pieces. Well, you may think this might just be a coincidence. However, try as many times as you want but will never get only two pieces. Now, isn’t that strange? Something that’s not expected the case to be.
Well, its no more a mystery. It took physicists and mathematicians years to understand this, but now they finally know how to explain the phenomenon.
The Spaghetti Conundrum
If this confuses you, nothing to worry about. The spaghetti conundrum has confused scientists for decades. Even the renowned and ever-curious physicist Richard Feynman was fascinated by this. In his own account, he spent an afternoon breaking spaghetti in halves and wondering why they don’t snap in two. He couldn’t come up with a satisfying explanation, and the mystery remained unsolved until 2005 when physicists from France came up with a working theory.
They found that when a single spaghetti — and for that matter, any long rod — is bent at the ends, it will break near the center, where it is most curved. But as it breaks, triggers a “snap-back” effect, producing a bending wave, or vibration, which further breaks the rod. The theory was demonstrated, and as a reward for their trouble, the French physicists received an Ig Nobel Prize, a parody of the Nobel Prize, which celebrates unusual or trivial findings.
But even after this, a question remained: is it never possible to break a single spaghetti in two? The answer is ‘yes’, with a twist — as in if you twist them, you can break them in only two. Researchers report that if you also twist the spaghetti, this dampens the shock wave and reduces the chance of breaking into several pieces. Essentially, if a spaghetti is twisted past a critical degree, then slowly bent in half, it will break in two.
The spaghetti can be broken in two by adding a 270-degree twist, due to the snap-back and twist-back effects working together.
The two students Dunkel is referring to are Ronald Heisser, now a graduate student at Cornell University, and Vishal Patil, a mathematics graduate student in Dunkel’s group at MIT. Their co-authors are Norbert Stoop, instructor of mathematics at MIT, and Emmanuel Villermaux of Université Aix Marseille. They designed a device that can controllably bend and twist spaghetti ends, focusing on two types of spaghetti: Barilla No. 5 and Barilla No. 7, which have slightly different diameters.
“They did some manual tests, tried various things, and came up with an idea that when he twisted the spaghetti really hard and brought the ends together, it seemed to work and it broke into two pieces,” Dunkel says. “But you have to twist really strongly. And Ronald wanted to investigate more deeply.”
Meanwhile, Patil developed a mathematical model to explain this behavior, building on the previous work done by French scientists Basile Audoly and Sebastien Neukirch, who first studied this behaviour. Putting all the hard work together, they finally solved this unusual puzzle — but there is one caveat.
Their study works on the assumption of cylindrical shapes — in other words, it only works for “classic” pasta. Other types of pasta, like fussili or linguini, will have a different behavior because they also have a different geometry.