MIT Scientists Finally Figure Out the "Spaghetti Problem" That Baffled a Nobel Prize-Winner

Tuesday, 14 August 2018 - 12:17PM
Physics
Tuesday, 14 August 2018 - 12:17PM
MIT Scientists Finally Figure Out the "Spaghetti Problem" That Baffled a Nobel Prize-Winner
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Image Credit: Pixabay Composite
Ever since Richard Feynman spent an evening in his kitchen with a bag of spaghetti rods, the infamous "spaghetti mystery" has haunted physicists. You can try it out for yourself, if you want: hold a long piece of dry spaghetti by both ends and bend it until it breaks, using equal pressure on both sides. You'll find that it's impossible to break the rod into two clean pieces. Instead, the rod always breaks into three or more fragments. The mystery of why this happens drove Feynman (and many subsequent physicists) nuts, becoming one of those weird experiments physics students do for fun (like "tickling the dragon's tail").

The mystery was finally solved in 2005 (and won the researchers an Ig Nobel Prize for unusual achievements in scientific research): when the spaghetti finally snaps in one place, the newly broken end tries to flex back to its original shape, but the force of this "snap-back effect" is so strong that it actually creates another fracture, which has the potential to then create a third snap-back.

That's one question answered, but a more important problem remained: whether spaghetti could ever be snapped cleanly in two, or whether the snap-back effect was insurmountable. Thanks to a couple of bored MIT students, we finally have an answer.

To explore this dilemma, the pair custom-built a machine that could bend and twist spaghetti. They found that they could counteract the snap-back effect (which is just a wave of energy traveling through the spaghetti rod) by twisting the rod almost 360 degrees, then bending it to the breaking point. The wave caused by the spaghetti rod untwisting itself canceled out the snap-back, allowing the rod to split into two pieces. The students even caught this effect on-camera, with a video that can record up to a million frames per second.

You might be wondering if these students were victims of some cruel physics instructor's prank to waste their tuition by encouraging them to build a spaghetti-snapping machine – but it turns out this study may help researchers understand how to control fractures in "multifiber structures, engineered nanotubes, or even microtubules in cells." Steel struts suffer the same brittleness and types of fractures. What started out as a boring night in a small town could lead to new materials and building methodologies that make our entire infrastructure safer.
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