This case study describes how our research team conducted an individual differences research project in a middle school science classroom. The main goal of our work was to investigate whether individual differences in cognitive abilities predict individual differences in scientific reasoning in middle school students. In order to address our research questions, we needed to administer psychological measures of cognitive abilities to middle school students "as a group" in their classroom context. Work with these types of measures is usually conducted in a laboratory setting where participants complete each task individually with direct oversight from an experimenter. Because we did not want to disrupt multiple days of classroom instruction, we were unable to test the children individually. This case study summarizes how we were able to modify psychological measures for whole-class administration. In addition to describing how we modified each measure iteratively over two implementation cycles, we also discuss how we presented our research in the classroom context and the key role of our partnership with the classroom teacher. [This content is provided in the format of an e-book.]