The Secrets of Breaking Spaghetti

demonstration, slow motion and basic explanation

https://youtu.be/RwtXVW0IWEk?feature=shared

Dynamic Buckling and Fragmentation in Brittle Rods

They present experiments on the dynamic buckling and fragmentation of slender rods axially impacted by a projectile. By combining the results of Saint-Venant and elastic beam theory, they derive a preferred wavelength for the buckling instability, and experimentally verify the resulting scaling law for a range of materials including dry pasta.

https://www.phy.olemiss.edu/%7Ejgladden/cv/buckling_prl.pdf

Fragmentation of Rods by Cascading Cracks: Why Spaghetti Does Not Break in Half

When thin brittle rods such as dry spaghetti pasta are bent beyond their limit curvature, they often break into more than two pieces, typically three or four. In this paper they find that the sudden relaxation of the curvature at this end leads to a burst of flexural waves, whose dynamics are described by a self-similar solution with no adjustable parameters.

http://www2.mat.dtu.dk/education/01999/SpaghettiCracking.pdf

Spaghetti Breaking Dynamics

They developed a simulation to obtain the desired number of broken segments of spaghetti by changing the diameter-to-length ratio.

https://www.preprints.org/manuscript/202103.0311/v1