You can explore the behavior of various granular mixtures using this virtual Hele-Shaw Cell. Press one of the five buttons on the left to select a mixture. Each mixture consists of two types of sand, one gray and the other white. Each may be one of three sizes: small, medium or large. Each consists either of smooth, spherical grains that are shaped like little balls, or rough, faceted grains with irregular surfaces.
See how each mixture behaves when poured into the Hele-Shaw Cell.