The Physics Of Noodles And Other Spaghetti Science

IRA FLATOW: This is Science Friday. I’m Ira Flatow. I love pasta. I love to cook it. I love to make pasta dishes. There are really two schools of thought about what to do with spaghetti. There’s those that slip the raw spaghetti strands whole into the boiling water. And then there are people like me who try to break the spaghetti into two pieces so it more easily fits into the pan.

But you know what happens– you find that it always breaks into three pieces and never cleanly into two. And it’s not just me. For decades, this humble food has prompted physicists from all over the world to try to understand pasta’s mysterious properties. Why can’t you break it into two pieces? And what’s in the secret sauce that makes cacio e pepe so hard to perfect?

Well, my next guest wrote about the scientists cooking up the answers to these questions and more. He did it for a recent piece for the BBC. Joseph Howlett is math staff writer at Quanta Magazine, based in New York City. Joseph, welcome to Science Friday.

JOSEPH HOWLETT: Thanks so much for having me, Ira. I’m a huge fan.

IRA FLATOW: I want to start with famous physicist Richard Feynman’s addition to the spaghetti science club. Not that I’m surprised, given the fanciful nature of his work, but how did he get hooked on studying this stuff?

JOSEPH HOWLETT: Apparently, it was one of his favorite foods. He noticed that if you hold both ends of a strand of dry spaghetti and break it, you can never break it cleanly into two pieces. And he wondered why that is. I guess Feynman just can’t turn his physics brain off. And him and his colleagues spent basically the entire night breaking pieces of spaghetti until the kitchen floor was covered with it. This is a piece of physics folklore now, that Feynman had this obsession with spaghetti.

IRA FLATOW: Wow. So this was just the beginning of his romance with spaghetti, right?

JOSEPH HOWLETT: Yeah, I mean, the question he opened up became a real line of research that hasn’t ended, even now. And people are still finding out the mysteries of breaking spaghetti.

IRA FLATOW: So how did other physicists build on this curiosity– on his curiosity?

JOSEPH HOWLETT: Well, for a long time, nobody could really understand what was happening until 2005, when a couple of researchers made a model that explained how it fragments and how the tension that you build in a strand of spaghetti distributes itself over the spaghetti so that it has to break in more than one spot at a time.

And this won an Ig Nobel Prize the following year, 2006. So this was kind of the ostensible answer to the question. But scientists have continued to study it. And just a few years ago, a group of MIT mathematicians figured out that you could break it into two pieces if you twist it first. I know it’s hard to imagine twisting a brittle strand of spaghetti. But with lab equipment, you can do it. You could twist it so well that there’s no tension in the middle. So that’s kind of distributed across the whole thing. And then if you break it, it’ll break perfectly in two pieces.

IRA FLATOW: The geek in me has to try this.

JOSEPH HOWLETT: You’ll end the night like Feynman, I’m sure, with the kitchen floor covered in spaghetti.

IRA FLATOW: I should be another Feynman. You write about another pressing issue, the spaghetti problem. When you suck spaghetti into your mouth, it always slaps in your face, doesn’t it?

JOSEPH HOWLETT: Yeah. You always end up with sauce on your face– or at least I did when I was slurping single strands of spaghetti as a kid. And a physicist and mathematician, George F. Carrier, was really intrigued by this problem and wrote a serious academic treatise on it. He called it the Spaghetti Problem. So he was basically wondering, as you slurp it in, why does it always slap the side of your face? Why can’t you slurp it in cleanly? And he was able to answer this with basic physics. It had to do with all of these different acoustic modes that come into play when you move something long and bendy.

IRA FLATOW: Let’s move on to figuring out the secret sauce. What drove Italian physicist to try to figure out the physics of why sometimes cacio e pepe fails to come together properly.

JOSEPH HOWLETT: Yeah, so there was this group of Italian scientists at the Max Planck Institute in Dresden. And they were lamenting how they would often be trying to make cacio e pepe and notice that the sauce, which is made of pasta water and cheese and nothing else, would sometimes suddenly form these big clumps that you could never break up. And you would have to throw out your entire batch of pasta.

And this was horrible for them, and it was particularly embarrassing when they would invite over their German friends and make a mess in front of them. So they decided to put together an apparatus to study why this happens and if there’s a way around it.

IRA FLATOW: And what did they discover?

JOSEPH HOWLETT: Fortunately for us, these Italian scientists are world-leading experts on the physics of phase separation, which is when you have a solution that’s a mixture of different things, and they form liquid droplets within the solution. That was key to them understanding what was happening when things clumped into what they called the mozzarella phase. For them, this was the phase separation that made a clump of cheese within the pasta that you couldn’t break up.

They figured out that this had to do with a couple of things. And what they realized was the pasta water has some starch, which is essential to mixing the sauce, but not quite enough to ensure that clumping doesn’t happen. So if you accidentally heat your pasta enough– and this could be a difference of a few degrees– they found that these clumps inevitably form. And the way around it, they decided, was to artificially add extra starch– more than the pasta water could supply. So they did this with corn starch. And if you add this extra little bit of starch, you can completely avoid the possibility of the mozzarella phase, regardless of how much you heat the sauce.

IRA FLATOW: Wow. It’s such a popular dish, you would have thought some famous chef would have figured this out instead of some scientists.

JOSEPH HOWLETT: That is exactly what they figured out. As they were writing the paper, they found a YouTube video of a famous Roman chef, a Michelin star chef, Luciano Monosilio, who had said exactly this in his video. He had said– he made a recipe for cacio e pepe where you add additional cornstarch and you can completely avoid this clumping phenomenon. It’s kind of a foolproof recipe. The researcher says it’s the only time they’ve ever cited a recipe in a scientific paper.

IRA FLATOW: All right, well, then they must figure out that there must be something that helps us better understand science or life on Earth when we understand the perfect recipe for cacio e pepe.

JOSEPH HOWLETT: Yeah, so it turns out that what happens when you mess up your cacio e pepe might be the same kind of accident that caused life on Earth to begin.

IRA FLATOW: Really?

JOSEPH HOWLETT: Yeah, because this phase separation stuff, forming clumps within a liquid, you can kind of imagine that in the primordial goop, where the things that were precursors to cells initially formed. You have this dispersed solution. And then you need the important stuff, the proteins, to find a way to all get together and build more complex molecules. And people think that may have happened due to the physics of phase separation.

IRA FLATOW: We’ve just talked about a few different studies, which raises the question, why are physicists so obsessed with spaghetti? I mean, it’s just flour and water, right?

JOSEPH HOWLETT: Exactly. And I think that’s part of the story. I mean, I was asking every scientist I talked to– what is it about spaghetti that gets you all so obsessed? One thing that came up a lot was exactly what you said, that it’s a very simple substance. It’s just flour and water. And yet, you get all of these complicated mechanical properties out of it. It’s brittle and stiff and strong, and it breaks in these weird ways. And yet, when you cook it, it becomes this springy, soft, pliable thing that you can tie into knots. It’s slippery, and it’s also kind of sticky. It’s just so many things at once with only two ingredients.

IRA FLATOW: And it’s cheap to experiment with.

JOSEPH HOWLETT: Yeah, that was a big part of it, too. The scientists who were breaking spaghetti in two, they said, yeah, we could have done this with brittle plastic rods. But they’re very expensive. You can’t be breaking them and filling your kitchen floor with them at the same price point that you can for a box of spaghetti.

IRA FLATOW: Are there any tips you can give us on cooking or preparing pasta, knowing the science, how it might help us?

JOSEPH HOWLETT: This story encourages me to try to have that same kind of curious mind as Feynman and others, to look for the science in the mundane and to maybe never turn off that part of your brain that asks, why is this like this?

IRA FLATOW: Yeah, he was very good at doing that. And you are very good at explaining it. I want to thank you for taking time to be with us today.

JOSEPH HOWLETT: Thank you so much, Ira.

IRA FLATOW: Joseph Howlett, math staff writer at Quanta Magazine, based in New York.

Copyright © 2025 Science Friday Initiative. All rights reserved. Science Friday transcripts are produced on a tight deadline by 3Play Media. Fidelity to the original aired/published audio or video file might vary, and text might be updated or amended in the future. For the authoritative record of Science Friday’s programming, please visit the original aired/published recording. For terms of use and more information, visit our policies pages at http://www.sciencefriday.com/about/policies/