This paper reports research from a three-year Australian science teacher professional learning project, the Science Teaching and Learning (STaL) Project, in which groups of science teacher participants (across years K-12) worked with academics over a one-year period as teacher researchers. Through reflecting on their experiences within the STaL Project and collecting data from their classrooms related to specific science teaching concerns, teacher participants constructed cases around particular aspects of their professional learning. The cases that these participants developed elicited rich insights into their teaching and their students' learning of science. This paper discusses how the cases were developed by the teacher researcher participants and uses exemplars as a way of illustrating the nature of the professional knowledge developed.