An on-going project is described which explores the creation of an effective learning environment for a large undergraduate survey course based on the theory of constructivism. The project utilizes technological innovations in the conversion of an information transmission model of teaching to an active-student, knowledge-construction learning environment, without sacrifice of class size. This effort has required close collaboration among content experts, computer scientists, educational theorists and instructional developers. The focus of the course is on the understanding of weather phenomena, and the primary vehicle for learning is an authentic activity where each student routinely predicts weather events and supports their prediction by identifying determining factors. This weather forecasting activity has been very successful in encouraging student participation and in promoting understanding in this course. The forecasts provide a continuing thread of meaningful discussion and motivation throughout the semester. Other learning activities involve simulated learning environments (Java-based simulations) and more standard evaluations of content understanding (short answer responses)