We explored how preservice teachers in a middle school science methods course learned and applied computational thinking (CT) concepts and activities during a month-long intervention. In the intervention, preservice teachers learned about CT concepts through an hour-long lecture in their methods class, practiced a computing-integration activity for electromagnetic waves, and prepared and implemented a lesson plan based on the activity in student teaching. The intervention was in the early stages of design, and, therefore, the research is exploratory with primarily qualitative data. The data were collected at multiple points throughout the month to measure the development of knowledge and attitudes about CT and computing integration. We found that preservice teachers had little knowledge of computing before the intervention that gradually evolved into a deep understanding that they wanted to apply to computing-integrated activities science and other subjects. Though they had high levels of uncertainty after initial instruction and practicing the computing-integration activity, they found the student teaching experience rewarding and motivating to including computing in their future teaching practice.