The effect of spherical projectile speed in ricochet off water and sand

Experimental results are reported for the ricochet of steel and duralumin spheres ( 3 8 in. and 1 in. dia.), from shallow depths of water and dry sand. The critical angle for ricochet off water is shown to increase with speed to approach the theoretical limit of 18 √σ deg. For ricochet off sand the critical angle decreases with speed but a cut-off angle exists, 82 √σ deg, for which no ricochet occurs at any speed.