How can digital games support conceptual learning? And how can games be made accessible and useful for teachers? Those are the questions addressed by Possible Worlds, a five-year research and development effort led by EDC. The project, funded by the U.S. Department of Education's Institute of Education Sciences, developed four modules of supplemental materials, each with a digital game as its centerpiece. The modules address topics covered in middle-school science, and each focuses on a persistent scientific misconception.