Terradynamics is the study of forces and movement during terrestrial locomotion (particularly that using legs) on ground that can flow such as sand and soil.[1] The term "terradynamics" is used in analogy to aerodynamics for flying in the air and hydrodynamics for swimming in water. Terradynamics has been used "to predict a small legged robot’s locomotion on granular media". The Johns Hopkins University Terradynamics Lab describes the field as "Movement Science at the Interface of Biology, Robotics & Physics".[2]