The authors discuss their efforts to transform a large introductory course for preservice early childhood and elementary teacher education majors and understand its impact on learners. The course was redesigned to align with the three-dimensional framework of the Next Generation Science Standards, emphasizing disciplinary content, cross-cutting concepts, and the practices of Earth science. Using a place-based storyline organized around a single stream watershed, each unit is tied to observations the students make in the field and online. A signature feature of the redesigned course is a student-driven investigation, in which groups plan and carry out their own study of our local watershed, then analyze and present their findings to their peers. Over three design cycles, we have refined the curriculum and collected data on student learning, motivation, and self-efficacy for science teaching using a combination of surveys, observation protocols, document analysis, and open-ended responses. We share our successes in reorganizing the introductory Earth science curriculum, integrating activity-based pedagogies into a large course, and increasing student science content understanding, as well as our difficulties impacting student motivation and self-efficacy for science teaching.