The mysteries of sand


I mean of course granular media which also includes powders, rice, asteroids and my favorite: sugar . They have so many funny and yet unexplained effects!


Think just about size segregation: You put a large red sphere on the bottom of a recipient filled with smaller blue ones, shake it and after some the big one is on top. The figure shows the starting of a simulation of this "Brazil nut effect" made with Jason Gallas , Thorsten Pöschel and Stefan Sokolowski (J. Stat. Phys. 82, 443-450 (1996)). The next picture shows what happens after some CPU-time has been spent. For more detail see our paper .

On granular materials I have also written several review articles like the proceedings for the school in Altenberg published in Physica A, Vol 313. 188-210 (2002) or an article with Stefan Luding published in Continuum Mechanics and Thermodynamics, Vol.10, 189-231 (1998) and popular articles in several languages including english , german , spanish , portugese and corean .

And here comes the largest sand grain I have ever seen (in Mamallapuram close to Chennay): Photo