The need to prepare students with twenty-first-century skills through STEM-related teaching is strong, especially at the elementary level. However, most teacher education preparation programs do not focus on STEM education. In an attempt to provide an exemplary model of a STEM unit, we used a rapid prototyping approach to transform an inquiry-based unit on moon phases into one that integrated technology in a meaningful manner to develop technological literacy and scientific concepts for pre-service teachers (PSTs). Using qualitative case study methodology, we describe lessons learned related to the development and implementation of a STEM unit in an undergraduate elementary methods course, focusing on the impact the inquiry model had on PSTs' perceptions of inquiry-based science instruction and how the integration of technology impacted their learning experience. Using field notes and survey data, we uncovered three overarching themes. First, we found that PSTs held absolutist beliefs and had a need for instruction on inquiry-based learning and teaching. Second, we determined that explicit examples of effective and ineffective technology use are needed to help PSTs develop an understanding of meaningful technology integration. Finally, the rapid prototyping approach resulted in a successful modification of the unit, but caused the usability of our digital instructional materials to suffer. Our findings suggest that while inquiry-based STEM units can be implemented in existing programs, creating and testing these prototypes requires significant effort to meet PSTs' learning needs, and that iterating designs is essential to successful implementation.