Over the past five years we have been conducting a Research Experiences for Teachers (RET) site program within the School of Chemical Engineering and Bioengineering. This program has many goals including; enhancing the instruction of science and mathematics at the middle school and high school level, promoting engineering as a major, and forming links between K-12 teachers and university faculty. With more than 50 teachers having participated in the program we now have data on what works and what does not in this type of venture. Acting on these observations we have significantly altered our approach for this year's program. The details of these changes, and their effects, will be highlighted.