With the growing adoption of the Next Generation Science Standards across the United States, elementary teachers are being called upon to incorporate engineering into their science instruction, creating a need for ways to help elementary teachers better understand what engineering is and how to accurately communicate it to students. The present study examines the effects of a teacher education and professional development project in which elementary student teachers and their cooperating teachers were teamed with engineering graduate students to incorporate engineering into grades 3-5 classrooms. By working alongside experts in engineering for a 16-week semester, the project aimed to help participating elementary teachers better understand what engineering is and what engineers do. To assess teachers' conceptions of engineering, we administered the Draw-An-Engineer Test as pretest and posttest. An important contribution of the present study is our development of a novel approach to analyzing responses from that instrument that is appropriate for adult populations and that also addresses multiple known shortcomings of drawing tasks. We found that from pretest to posttest, teachers' responses became clearer with respect to the processes that engineers use in their work, and they became more likely to represent flowchart models of "the engineering design process." The teachers' focus on process, however, was not shared by the engineers, indicating that the engineers were not simply conveying their own understanding of engineering to the teachers. Rather, the teachers constructed their own understanding of engineering work that deviated in certain ways from the views of the engineers.