Destin Sandlin of SmarterEveryDay on YouTube has been on a five-year quest to figure out why water sometimes balls up atop other bodies of water.
Why does it take water a little while to coalesce? And why do some water droplets keep hitting the surface repeatedly before coalescing?
This video covers the surface chemistry behind the phenomenon. It breaks down the visuals at 7,000 fps and slows down the event in stunning detail.