This study infused computer modeling and simulation tools in a 1-semester undergraduate elementary science methods course to advance preservice teachers' understandings of computer software use in science teaching and to help them learn important aspects of pedagogy and epistemology. Preservice teachers used computer modeling and simulation tools within their own science investigations; discussed general technology issues; and explored, evaluated, and taught their peers about a particular modeling tool. Preservice teachers expanded their vision of the software available and the role that software can play in science teaching, but desired fun, easy-to-use software with scientifically accurate information within a clear, familiar learning task. Such conflict provided a fruitful platform for discussion and for potentially advancing preservice teachers' pedagogical and epistemological understandings.