His entry was titled “Smoke on the Wind”. It is an image of the wake formed by smoke blown over a liquid drop suspended in the air by sound waves. The smoke is illuminated by a laser sheet giving it a blue color, the striations are formed by the motion of smoke particles in the light. The drop contains a fluorescent dye which glows green under the laser. He uses images like this to understand how particles are collected by drops in order to better predict how pollution is removed from the atmosphere by rain and how to design water sprays to remove more soot from smokestacks.