Where simulations are interesting and even exciting teaching tools is in the other extreme -- where the mapping from real to virtual is uncontroversial, but the consequences of these known interactions are unclear. This is generally the case when we are simulating physics. An orbit-integrator is a prime example: there's no question about how gravity works, we can demonstrate that pretty trivially from real-world experiments and observations. On the other hand, the consequences of this are extraordinarily complex and unpredictable. A simulator can run that math at high speed and show you what you can expect. Furthermore, the actual experiment is basically impossible. Even if you had the multi-million dollar budget to launch a real object into space, the actual playing out of the orbital mechanics takes years. A simulation lets you run that fast-forward. ================================================================== Further on yours and Ms. Creighton's -- in this century we'll move human cognition from philosophy to physics, leading to reasonable definitions for thinking and learning. Perhaps then Ms. Creighton will get better feedback. Dick S.