The purpose of this research was to identify preservice teachers' preconceptions about Earth scientists and investigate how these conceptions change after completion of an Earth science course and student investigation of Earth processes. Drawing on theory that supports sketching as a tool to investigate teacher beliefs, we asked 33 preservice elementary and middle school teachers to sketch an Earth scientist on the first day of class. Subsequently the preservice teachers embarked on a course of study aligned with the Next Generation Science Standards for Earth and Space Science for grades K-8. This included topics in weather, climate, geology, and the ocean, which naturally exposed the preservice teachers to a variety of Earth scientists. Furthermore, each preservice teacher conducted an Earth science investigation by generating a weather-related research question, collecting and analyzing authentic data, and presenting findings at a class poster session. Toward the end of the semester, we again asked the preservice teachers to sketch an Earth scientist and provide a brief written explanation. We scored the sketches and responses using an adapted scoring checklist based on the Draw-A-Scientist Test (DAST-C) to identify the preservice teachers' preconceptions and describe how they evolved over the course of the semester. Additionally, we conducted in-depth interviews to more fully understand the process of changing conceptions in two cases. Notably, we found that many preservice teachers began the course with little to no understanding of what an Earth scientist is. We document the evolution of conceptions as the preservice teachers conducted authentic Earth science investigations and participated in the course. We share implications for the design of Earth science courses intended for preservice teachers and broadening understanding of Earth science disciplines. Finally, as we continue to pursue this project, we invite instructors of similar courses to collaborate and contribute to our growing data set.