An anonymous reader writes: Years of research has gone into products that are hydrophobic — they resist getting wet. But nature solved this problem long ago, and it's ubiquitous outside our buildings and homes. You've probably seen it yourself, after a light rain: water collects in round droplets on many leaves from trees and plants, refusing to spread out evenly across the surface. This article explains why that happens using super slow-mo cameras and an electron microscope. "[T]he water isn't really sitting on the surface. A superhydrophobic surface is a little like a bed of nails. The nails touch the water, but there are gaps in between them. So there's fewer points of contact, which means the surface can't tug on the water as much, and so the drop stays round. ... [After looking at a leaf in the electron microscope,] we saw this field of tiny wax needles, each needle just a few microns in length! The water drops are suspended on these ultra-microscopic wax needles, and that keeps it from wetting the surface."