Why dry spaghetti shatters when you snap it

When you snap dry spaghetti before dropping it into the pot, it sometimes results in an explosion of shards. To understand the physics of the phenomenon, MIT mathematicians used computer simulation and a custom machine to break lots of sticks of spaghetti. It turned out that spaghetti that's twisted first reduces the strength of vibrations that cause more cracks. From Science News:

This strategy may not be much practical help in the kitchen; Patil and colleagues aren’t selling their spaghetti snapper for $19.95 — and even if they were, meticulously twisting and bending pieces of pasta one-by-one is hardly efficient meal prep. Still, the discovery of the bend-and-twist technique may lend new insight into controlling the breakage of all kinds of brittle rods, from pole vault sticks to nanotubes.

And from their scientific paper in PNAS:

Fracture processes are ubiquitous in nature, from earthquakes to broken trees and bones. Understanding and controlling fracture dynamics remain one of the foremost theoretical and practical challenges in material science and physics. A well-known problem with direct implications for the fracture behavior of elongated brittle objects, such as vaulting poles or long fibers, goes back to the famous physicist Richard Feynman who observed that dry spaghetti almost always breaks into three or more pieces when exposed to large bending stresses. While bending-induced fracture is fairly well understood nowadays, much less is known about the effects of twist. Our experimental and theoretical results demonstrate that twisting enables remarkable fracture control by using the different propagation speeds of twist and bending waves.