Hand-washing model uses fluid mechanics to track harmful particles. Peer-Reviewed Publication AMERICAN INSTITUTE OF PHYSICS IMAGE: ONE CASE OF A PARTICLE’S MOVEMENT. IT BEGINS AS THE RED POINT, RESTING ON THE SURFACE OF THE HAND (BLACK WAVY LINE). IT FOLLOWS THE BLUE PATH, ESCAPING THE HAND AND THEN MOVING FREELY THROUGH THE HAND-WASHING FLUID. view more CREDIT: PAUL...