Why does a stone bounce off the surface of the water? Why does a bullet bounce off of the surface when it strikes a material at an angle? When I was learning about why glass water bend light, the use of a toy car rolling over different surfaces was used. The slowing down of one side of the car made it steer in that direction. Likewise, light acts similarly when striking glass at an angle. So why don't other objects do this? When you try and bounce a stone off the water, the stone hitting the surface of the water should slow down causing it to steer into the water. Same thing when a bullet hits the surface of anything it can go through, it should steer into the slower medium. So why do they bounce off instead? And for that matter, why do things bounce? I never got ho Newton's cradle worked. Personally, I think it's witchcraft.