I read somewhere, long ago - I think it was in Scientific American - that they had found that the drop of water that hits the surface does not mix with the water it hits, instead bouncing because of the surface tension. There were photographs, and I believe it was a blue drop of water bouncing off of red water - something that most people wouldn't find interesting, but something that is when it is considered. The drop that creates the ripple does not get absorbed until if falls back again - when the ripple has already started across the surface.

Change bounces on the surface tension of the status quo. Rippled might cause the surface area to increase and also the angle of incidence of the drop to the surface to change until the drop is absorbed. A secret life of a water drop. For a drop to have an effect, it does not have to become a part of the system... it must only bounce. And by bouncing, the status quo is changed enough for the change to be absorbed. This isn't something that I have studied in a laboratory, but I imagine that it is true after watching many drops of water closely over the period of my life. { Read more }