ELASTIC3S (Embodied Learning Augmented through Simulation Theaters for Interacting with Cross-Cutting Concepts in  Science) is an NSF Cyberlearning research project conducted by an interdisciplinary team of learning scientists and computer scientists at the University of Illinois at Urbana-Champaign. The goal of this project is explore ways that body movement can be used to enhance learning of “big ideas” in science. We are developing new techniques for tracking and recognizing the hand and body movements of K12 learners so that they can interact in expressive ways with simulations from a range of topic areas in geology, chemistry, biology, etc. We are conducting interviews with high school students in Central Illinois to try and better understand how their gestures and other body actions facilitate reasoning with the cross-cutting concepts outlined in the Next Generation Science Standards, and we are integrating these findings into the design of immersive “simulation theaters” that embed learners within important science phenomena.