28 August 2005

Spaghetti Doesn't Snap in Two

[This is probably of "interest" only to B.B., but who knows.]

The PBS documentary The Best Mind Since Einstein is about the life and achievements of Richard Feynman. It includes clips of world-class scientists like Hans Bethe and Danny Hillis sharing their memories of Feynman.

One segment stuck in my head since 1993. Hillis recounted how he and Feynman spent hours in the kitchen snapping raw spaghetti to try to get it to break in two segments rather than three, coming up with various theories about why it refuses to break in two. Evidently Hillis's story is also in No Ordinary Genius, which parallels the documentary:

If you get a spaghetti stick and you break it, it will almost always break into three pieces. Why is this true -- why does it break into three pieces? We spent the next two hours coming up with crazy theories. We thought up experiments, like breaking it underwater because we thought that might dampen the sound, the vibrations. Well, we ended up at the end of a couple of hours with broken spaghetti all over the kitchen and no real good theory about why spaghetti breaks in three.
Well, wait no more! B. Audoly and S. Neukirch of the Universite Pierre et Marie Curie have posted videos and scientific articles about the science of spaghetti-snapping. Their paper (pre-print?) in Physical Review Letters, "Fragmentation of rods by cascading cracks: why spaghetti do not break in half" is online. I like Fig. 4, comparing Barilla Nos. 1, 5, and 7, whose caption begins, "Space-time diagram, in rescaled coordinates, of the breaking events obtained by repeating the experiment [...] for different pasta radii and initial curvatures [kappa-naught]."

By the way, the Vega Science Trust has four free online videos of Feynman giving The Douglass Robb Memorial Lectures.

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1 comment:

La Lecturess said...

This is so cool. I'm a sucker for at-home science projects (maybe because I can't understand the non-at-home kind).