I know your answer: It splashes because…it’s water. (Hah! Gotcha!)
Apparently, it’s not as simple as that. Dr. James Sprittles from the Mathematics Institute at the University of Warwick in England theorized
why a drop of liquid doesn’t just fall evenly onto a surface but instead, causes a splash. According to him, the culprit is a microscopically thin layer of air below the water drop that gets trapped between the drop and the surface, causing parts of the liquid to fly off. And by tiny he means about fifty times smaller than the width of a human hair
He also captured the microscopic dynamics of water under varying liquid viscosity and air pressure condition, thus, enabling him to differentiate the results. He found that the lower the air pressure, the lesser the splashing phenomena due to the increased likelihood of this thin air layer to escape. This is why there are less splashing in mountaintops where the air pressure is reduced.
Well, who cares? Right?
Dr. Sprittles said, “You would never expect a seemingly simple everyday event to exhibit such complexity. The air layer’s width is so small that it is similar to the distance air molecules travel between collisions, so that traditional models are inaccurate and a microscopic theory is required. Most promisingly, the new theory should have applications to a wide range of related phenomena, such as in climate science – to understand how water drops collide during the formation of clouds or to estimate the quantity of gas being dragged into our oceans by rainfall.” This new finding can even provide insights in blood-spatter forensic analysis (sounds like something they could use in the movie How to Get Away with Murder).
“Small but terrible,” as the famous adage says. Indeed even the tiniest bit of information in our life can help us come up with new advancements that can better our lives.