What is rheology? Most people are familiar with the basics of rheology from experience with diarrhea or perhaps rheostats. The word rheology was invented in 1929 to name the discipline of a society engaged in the study of how materials deform in response to forces. It was inspired by a quote by Heraclitus: “παντα ρει” translated as “everything flows”. Indeed everything does flow, but to different extents depending on how much force is applied, in what direction, and for how long. For materials more complex than simple springs, where a spring constant relates force to elongation, the goal of rheology is to provide quantitative parameters that define how a material will deform as a function of force,time and spatial orientation.