The capability of computers and algorithms to solve once-intractable problems arising in physics gives new media artists powerful tools for communication and creation. In this paper, we will present two common methods for simulating a variety of physical systems: one based on discretizations of field values onto cells, and the other onto particles. We will draw parallels between these and much simpler Cellular Automata, and give many examples of work using a variety of methods. Although the emphasis will be on fluid dynamics, the equations and algorithms summarized herein are applicable to many fields of physics.