Dec 18, 2014
When droplets on a superhydrophobic surface coalesce with one another, they jump. Individually, each drop has a surface energy that depends on its size. When two smaller droplets coalesce into a larger drop, the final drop’s surface energy is smaller than the sum of the parent droplets. Energy has to be conserved, though, so that excess surface energy gets converted to kinetic energy, causing the new droplet to leap up. Smaller droplets have higher jumping velocities. For more, see the original video. (Image credit: J. Boreyko and C. Chen, source video)
