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Physics Reveals How to Break Spaghetti Cleanly In Two

Our collective culinary nightmare is over

Science (MIT)
smithsonian.com

In 2005, scientists confirmed something pretty much everyone already knew: dry spaghetti noodles never break cleanly in two. Instead, they fracture into three or more pieces, leaving little dry noodle bits all over the stove and kitchen floor if you don’t aim properly. But now, reports Frank Swain at New Scientist, our long culinary nightmare is over. Researchers at MIT have figured out how to snap spaghetti in two cleanly, without creating any noodle shrapnel.

It turns out, the quest to understand the deep mysteries of spaghetti go way back (and has nothing to do with the Flying Spaghetti Monster). No less than Richard Feynman, the Nobel-prize winning physicist put his noodle to the question, spending an evening with a friend snapping pasta trying to figure out what was going on. He never did solve the conundrum, but his efforts inspired researchers from France to dig into the tangled mess, which earned them a 2006 igNobel prize.

Spaghetti is, essentially, a long, thin rod (that happens to pair exceptionally well with a little Bolognese and some parmesan). To break it requires bending it into a bow shape. Eventually the force of the bend snaps the rod in the middle where it is most curved. But the physics doesn’t end there. That break releases energy back down the pieces of spaghetti in a “snap-back” wave or vibration. There’s enough energy in those waves to break off smaller lengths of pasta.

Two MIT students, Ronald Heisser and Vishal Patil wanted to see if there was a way to counteract the snap-back and make the pasta break evenly as the final project for a Nonlinear Dyanmics class. Their instructor, Jörn Dunkel, co-author of their paper in the journal PNAS, says the duo played around with some spaghetti, manually breaking it and discovered that by twisting the pasta very hard, they could get it to snap in two.

To look into the phenomenon more deeply, they built a mechanical spaghetti snapper, which allowed them to twist the pasta at various degrees before bending it. They twisted and snapped hundreds of noodles, recording the action using a high-speed camera. What they found is that by twisting the dry noodles 360 degrees before bending them, they could get them to break in two. The trick works on Barilla No. 5 and Barilla No. 7 spaghetti, but there’s no word if it works on DaVinci, Ronzoni or the stuff you get at the farmers' market. And Dunkel says it only applies to long rod-shaped pasta. Flat noodles like linguini have a whole different set of physics. And rotini? That’s stuff is just quantum-level weird.

So why does the twist work? The researchers found that the energy normally released by the break is diverted from the snap-back into a twisting motion. That “twist wave” travels faster than the snap, dissipating its energy. “Once it breaks, you still have a snap-back because the rod wants to be straight,” Dunkel says in a press release, spaghetti “But it also doesn’t want to be twisted. That’s why you never get this second break when you twist hard enough.”

The study may have some implications for two and three-dimensional fracture dynamics. But mainly it was just a chance to try and understand the everyday world via science. “It’s just one of those intrinsically interesting things that goes on around us,” Dunkel tells Swain. “We work on a lot of things here but 10 per cent of them should be fun.”

While the physics behind dry pasta seem to be lined out, the mysteries of cooked pasta, however, are just starting to be unraveled.

About Jason Daley

Jason Daley is a Madison, Wisconsin-based writer specializing in natural history, science, travel, and the environment. His work has appeared in Discover, Popular Science, Outside, Men’s Journal, and other magazines.

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