A microworld for learning about ecology: every action has a consequence! Whether planning a mission to Mars or imagining improvements to their own environments, kids can change conditions inside the Biosphera and observe perturbations in the system. The microworld enables changes to environmental parameters such as light, humidity, temperature, chemical conditions, and populations of micro-organisms. A computer interface works with sensors and actuators to control the physical world of the Biosphera. This interplay of perceptual accessibility and virtual representations supports experimentation and learning about biology, chemistry, and dynamic systems.