David Cannell was trained as a condensed matter experimentalist and worked as a professor of physics at UC Santa Barbara from 1970 until 2012. His research interests include laser light scattering, polymers, complex fluids, phase transitions, convection, and the behavior of thermal fluctuations in liquids subjected to a temperature gradient. He always enjoyed teaching, especially the lower division non-majors, many of whom make major adjustments in their mental processes after taking their first physics course. Most recently, David developed an experiment called GRADFLEX, which was funded by NASA (National Aeronautics and Space Administration) and ESA (European Space Agency) with the intention of measuring the properties of spontaneous thermal fluctuations in fluids and mixtures subjected to temperature and/or concentration gradients, here on Earth and in microgravity. The experiment was flown quite successfully as part of the Foton M3 mission in September 2007. This work was done in collaboration with Professors Marzio Giglio and Alberto Vailati of the University of Milan.