What the hell is going on with these balls?

Two glass spheres are dropped into a pool of resting water. The sphere on the left causes almost no splash at all, while the one on the right looks like it's doing an impression of your cousin Joey pulling a cannonball at the community pool. The balls are the same size, shape and material. What gives? » 7/10/13 2:49pm 7/10/13 2:49pm