Laboratory experiments related to the physics and chemistry of clouds frequently require the examination of single raindrops. Existing techniques using freely falling drops or a charged drop suspended in an electric field are often unsatisfactory for a variety of reasons. A new technique, using acoustic levitation and the object of this research, would enable new measurements to be made in the laboratory. This device exploits acoustic standing waves to accurately control the loaction of a single drop or crystal without direct physical contact. Professor Hansman is a young scientist and a recent recipient of a Presidential Young Investigator award. He was trained as an engineer and highly qualified to carry out the proposed work. The ability to suspend a water drop or crystal and to manipulate it with ease could benefit many laboratory investigations in meteorology, particularly cloud physics, and atmospheric chemistry. I recommend supoprt as a two-year continuing grant at the revised budget level.
