Dr. Shaw's research involves the physics of the earth's atmosphere, with an emphasis on clouds and experimental tools for studying clouds. Clouds are transient collections of particles that interact strongly with visible radiation: they are transient in the sense that the particles in a cloud are continuously evolving in size and thermodynamic phase (liquid versus ice), and the cloud itself dissipating if the particles are not continuously "fed" through atmospheric motions or radiative cooling. Research in Shaw's group has focused on understanding the influence of turbulence on cloud particle growth through condensation and collisions, and on understanding the nucleation process through which ice forms from liquid water. Shaw's group is actively involved in the development of methods for studying clouds in controlled conditions in the laboratory as well as in the atmosphere itself. For example, digital holography is applied to particle tracking in turbulent laboratory clouds, and to measurement of particle size distributions in clouds sampled by research aircraft. More details are available at the Cloud Physics Laboratory web site.