The research experiences for teachers program at Central Michigan University was initiated to team in-service and pre-service teachers with undergraduate engineering students and engineering faculty, in an engineering research setting. During the six-week program, teachers learn engineering concepts and develop high-school instructional material following the new Next Generation Science Standards, so they can bring experiences back to their high school science classrooms. The program has completed its second year. This paper presents a program overview, changes made for the second year based on first year results, assessment of the teachers' experiences and understanding of engineering, and lessons learned by everyone involved.