During summertime, a physical phenomenon can be observed in a fresh drink. Consider your favorite cocktail in a long drink glass you filled with a lot of ice cubes. The packing of the ice blocks is slowly melting. Suddenly, this assembly of floating ice rocks becomes unstable and all cubes moves towards another equilibrium state. A new period of calm takes place before the next collapse.

In careful experiments, we measured the apparent and the true volumes occupied by a large set of ice cubes over a long period (up to 35 hours). We characterized the statistics for the slow evolutions of the system and for the huge fluctuations corresponding to global reorganizations of the random assembly. We discovered that this particular dynamics is similar to the fracture of an object submitted to an external constraint. By using X-ray tomography, we were able to investigate the evolution of the 3D structure before and after a collapse. We show that starting from random configurations, the ice cube system becomes more and more ordered, especially along the borders of the container. The information collected along this work brings new insights on the granular properties made of melting particles. This problem is echoed in melting rocks dynamics studied in geology and sintering processes in material sciences.

After reading this article, you will never look at your favorite cocktail as before !

S.Dorbolo et al., Phys. Rev. E 85, 051310 (2012) – PDF