Density Relaxation When a granular system is tapped, the density can relax. Simulation of Small particle system http://gsl.njit.edu/wordpress/wp-content/uploads/2013/09/SubmittedMovie-3.m4v Small system http://gsl.njit.edu/research/simulations/smallcase_density.mp4 Large system http://gsl.njit.edu/research/simulations/largecase_density.mp4