The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time. However, if the drop of water falls into water, splashes decrease and disappear over time, which looks like a decrease in entropy. How does it comply with the second law?
It seems to me that the potential energy of the original drop is ultimately converted to internal energy of the pond water (including the original drop) and the surrounding air (and everything else surrounding). So the entropy of everything afterwards is a little higher than everything before, and roughly equal to the potential energy of the original drop divided by the absolute temperature of the pond, air, and greater surroundings. So, in this essentially large-scale isolated system, as expected, when a spontaneous process takes place, the entropy of the system increases.