The pasta problem

August 15, 2005 8:13 PM

It was one of the great riddles of the cosmos. Along with black holes, the structure of space-time and the origins of the Big Bang, some of the greatest scientific minds have struggled with the dry spaghetti question. Why does uncooked spaghetti snap into more than two pieces when bent?
posted by Wet Spot (23 comments total)

because I said so?
posted by tiamat at 8:18 PM on August 15, 2005

That's a great web version of what is probably a really technical paper.

The reason they come up with is completely unintuitive. I know I wouldn't believe you if you told me spaghetti could break just by bending it and letting go.
posted by smackfu at 8:30 PM on August 15, 2005

I don't understand. The article says that pasta breaks in THREES, but that has never been the case with me. It always breaks into SEVERAL pieces. In fact, the pic in the articles shows it breaking into several pieces!
posted by braun_richard at 8:40 PM on August 15, 2005

Umm no, the article states that pasta breaks into multiple pieces (AT LEAST 3).
posted by drpynchon at 8:51 PM on August 15, 2005

I guess I just don't know why pasta breaking into multiple parts is such a surprise. I mean, it's a brittle, thin substance, and it will break into multiple parts.

Of course, getting pasta to break into two pieces is extremely easy, if you're careful and hold it correctly.
posted by braun_richard at 9:01 PM on August 15, 2005

BTW, I was just playing with this and I can't reproduce their experiment at all. If I hold one end and bend the other and let it go (like their catapult effect), it either doesn't break, or it breaks when I'm bending it. It never breaks when I let it go. Maybe I'm missing something.
posted by smackfu at 9:06 PM on August 15, 2005

Really cool. I have often wondered if their are great discoveries waiting to be made in mundane things like this. You don't need (necessarily) black holes or electrodynamics or the model of the atom to come up with brand new physics.

braun_richard: the way spaghetti breaks is not at all intuitive to me. If I bend a stick, it breaks at one point, not three of four or five. I would expect a single point of failure, at which point tension is released, so no more breaking should happen. It's not being hit with a hammer, it's being bent until it breaks.

Their explanation is fascinating, as it appears that a release of tension increases force. Cool.
posted by teece at 9:08 PM on August 15, 2005

*Starts melting cheese*
posted by PareidoliaticBoy at 9:57 PM on August 15, 2005

I did not rtfa - heterogeneity in extruded flour amalgam.
posted by PurplePorpoise at 10:14 PM on August 15, 2005

Flexural waves, baby! Thanks, Wet Spot!
posted by shoepal at 10:14 PM on August 15, 2005

I'm glad that others are also overwhelmed by the everyday physics that plagues everyday activities.
posted by Balisong at 10:16 PM on August 15, 2005

I have often wondered if their are great discoveries waiting to be made in mundane things like this. You don't need (necessarily) black holes or electrodynamics or the model of the atom to come up with brand new physics.

In Surely You Must Be Joking, Mr. Feynman Richard Feynman describes being at [some job in some prestigious university] and being totally stuck as to what to study. He went to the cafeteria one day and noticed a plate spinning on the table, and observed how the pattern on the plate seemed to rotate at a different rate than the plate as a whole was rotating (it wasn't really rotating; it was precessing) and then he came up with [some great physical theory that I don't remember or understand].

So, you know, that's like, how it happens sometime, right? I guess. I don't know.
posted by Turtles all the way down at 10:18 PM on August 15, 2005

*Minces the garlic*.
posted by PareidoliaticBoy at 10:41 PM on August 15, 2005

The brittle steel struts in skyscrapers, buildings and bridges can fragment by similar mechanisms, so this research can have practical implications in helping to make structures safer.

Libretto to a Spaghetto:
Most bridges are brittle
if not cooked a little.
I like mine al dente,
with a ’90 Chianti.
posted by weapons-grade pandemonium at 11:37 PM on August 15, 2005

Speaking of Feynman, what's the answer to the sprinkler-drain question? (spell check is not kind to Mr. Feynman)
posted by 517 at 6:26 AM on August 16, 2005

It doesn't spin.
posted by wilberforce at 6:36 AM on August 16, 2005

“Their explanation is fascinating, as it appears that a release of tension increases force”

Having no small experiance with both spaghetti & breaking things my first reaction was that the spaghetti was brittle and after being radically bent the force from snapping back probably stressed it even more.

So these guys conclude that the pasta is broken up by flexural waves.
Don't I feel like an asshole.

But that's why you contract at the point of contact (then release) when you strike something. That muscle tension prevents the reiteration of that wave back into you, it also helps focus force into the target. It's why the Shaolin backfist works, and yet is worthless when covered in maranara sauce.
posted by Smedleyman at 8:05 AM on August 16, 2005

It breaks as such because it is his divine will
posted by cmfletcher at 8:49 AM on August 16, 2005

If I hold one end and bend the other and let it go (like their catapult effect), it either doesn't break, or it breaks when I'm bending it. - smackfu

if i understand you correctly, you're merely bending the spaghetti before letting it go, right? like if you were gonna fling something from one end of it? the experiment as i understood it was that they'd break a piece of dry spaghetti. initially, it would break in one place, and the catapult effect (ie flexural waves) originates from the breaking point with as much force as is needed to break the spaghetti again (and in some cases again and again).

does that make any sense? i can't tell as i'm used to pondering dinner later in the day.
posted by carsonb at 9:05 AM on August 16, 2005

...the initial break sends waves rippling down the length of the pasta. This wave boosts the curvature of the already bent pasta, triggering a cascade of other breakages, which, in turn, trigger more waves, causing the strand to fragment.

It seems sensible that smaller strands break with less curvature, but they would also require more force to break.

If you hold one end of the spaghetto with your left hand and bend the other back with your right finger until it breaks, the latter end flies off and breaks again in mid-air. It appears the damping of the left hand causes the energy of the whole to be transmitted to the flying piece. So there's not more energy out than in; it's just redistributed.
posted by weapons-grade pandemonium at 9:38 AM on August 16, 2005

..as with a slingshot.
posted by weapons-grade pandemonium at 9:41 AM on August 16, 2005

This is really cool. I had never thought to think about it before, but now I feel like I missed out on thinking about the riddle before it was solved.
posted by OmieWise at 10:03 AM on August 16, 2005

So dry spaghetti experiences whiplash?
posted by Citizen Premier at 10:11 AM on August 16, 2005