Science & Technology

Here's Why Spaghetti Always Breaks in Three

Every time you try to break a piece of spaghetti in half, it shatters everywhere, usually into three, four, or even five pieces. The reason this happens has actually puzzled scientists for decades — but recent research has finally found an answer.

The Way the Noodle Breaks

If you take an uncooked spaghetti noodle and try to break it, something puzzling happens. The noodle doesn't just snap in half; it practically shatters, spraying uncooked spaghetti noodle all over your kitchen. The reason why has vexed scientists — even Nobel prize-winning physicist Richard Feynman is known to have pondered the question, but unfortunately, he didn't live to see the answer.

In 2005, French scientists Basile Audoly and Sebastien Neukirch finally nailed down the solution to the famed spaghetti problem. They conducted an evaluation of spaghetti noodles, treating them as simply "brittle rods," to determine the exact way in which they fractured under a force. They found that when you bend a rod like a spaghetti noodle by applying equal force to each end, it snaps in two. But then something weird happens: After this first break, the pieces flex backward, creating a series of flexural, or bending waves. These waves then break the spaghetti into more pieces.

This discovery of spaghetti physics — aka "thin rod physics" — made headlines in 2005. It was the solution to decades of study from world-class minds.

Can You Break a Noodle in Two?

Of course, knowing why a spaghetti noodle breaks the way it does is one thing. But can you stop it from happening? Recently, a group of MIT researchers investigated whether it's possible to break a spaghetti noodle into two pieces exactly. What they discovered was published in the journal PNAS last August.

The team thought they might be able to counteract the flexural waves that cause noodles to shatter by applying some kind of torsion, or twisting force, to the noodle. That was the theory, but they needed a way to test it.

MIT scientists went on to build a machine that would hold a spaghetti noodle and allow them to apply precise forces to each end. After running through thousands of noodles in thousands of tests, they found that if you twisted the noodle just-so, then applied equal forces to each end, the noodle would break into just two pieces.

Specifically, the team found that if you twisted the uncooked noodle 270 degrees and then bent the ends at 3 millimeters per second, the spaghetti would break perfectly. The twisting snapback after breaking was enough to counteract the flexural waves and prevent any further breakage, just as they thought.

Watch It Happen

The team went further than just snapping spaghetti noodles in a lab — they also snapped in a computer model. That allowed the team to predict and snap noodles of differing variables virtually. For example, the team used it to determine the exact point at which a noodle would break into four pieces rather than three or two.

This new understanding might help materials scientists prevent materials from cracking or snapping under pressure. As for what it means for you, the spaghetti consumer? Well, with a little bit of practice, you might be able to perfect a nifty dinner party trick.

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Written by Trevor English April 22, 2019

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