A version of the classic rotationally resolved infrared (IR) spectrum of a diatomic molecule experiment has been developed using the POGIL framework to more fully engage students in the collection, modeling, analysis, and interpretation of the data. An analysis of the experimental protocol reveals that the POGIL approach actively engages students in scientific practices. The student learning objectives for this laboratory experiment are to (1) develop an energy level diagram and relate that diagram to rotational-vibrational spectra; (2) identify, describe, and interpret the molecular constants that can be extracted from gas-phase IR spectra; (3) discover the impact of spectral resolution on precision of molecular constants derived from the spectral data; and (4) use data to evaluate and refine quantum mechanical models. The learning cycles, analysis of student engagement with scientific practices, and reflections from instructors are described.