When balloons burst, they either split open along a single line or, if inflated to a high pressure, shred into many pieces.

Sébastien Moulinet and Mokhtar Adda-Bedia at the École Normale Supérieure in Paris punctured rubber balloons and used a high-speed camera to film the popping process, which lasts for less than 0.1 milliseconds. The stress within the membrane depends on the balloon's internal pressure and on the membrane's thickness and curvature. The authors found that as membrane stress increased, a single crack propagated at higher speeds. Above a threshold level, the crack branched out into as many as dozens of cracks to quickly dissipate the stress, leading to many balloon fragments.

The researchers say that similar principles might cause the tree-like propagation of cracks in processes ranging from the breakup of atomic nuclei to the collisions of asteroids.

Phys. Rev. Lett. 115, 184301 (2015)