Collision of a sphere onto a wall coated with a liquid film
  Particle-particle and particle-wall collisions occur in many natural and industrial applications such as sedimentation, agglomeration, and granular flows. To accurately predict the behavior of particulate flows, fundamental knowledge of the mechanisms of a single collision is required. In this fluid dynamics video, particle-wall collisions onto a wall coated with 1.5% poly(ethylene-oxide) (PEO) (viscoelastic liquid) and 80% Glycerol and water (Newtonian liquid) are shown. 
A.M. Ardekani and R.H. Rangel