Impact Dynamics in “Hard” and “Soft” Granular Matter

Abstract

Using a wireless accelerometer, we explore the dynamics of penetration of a sphere falling into very light granular matter prepared with different compactions. The duration of the penetration process until the sphere stops is ~30% bigger for less compacted granular matter, while the maximum penetration depth is ~40% bigger in that case. These outputs are quite remarkable, considering that the differences in the filling factors of the two granular media were smaller than 5%.