Significant attention is being paid to the needs for transformation within the fields of science, technology, engineering, and mathematics (STEM) education at the undergraduate level. This talk examines how *STEM disciplines, physicists, and physics departments in particular, are positioned to contribute to these discussions and address our challenges. We will review our own efforts to improve physics education and the growth of work in physics education research (PER) at CU Boulder. Our experimental work develops a line of inquiry in PER through investigations at the individual,course, department, and institutional scales. We present samples of these scales, reviewing how we can build on understanding of student reasoning, studies of how our environments do and do not support women in physics, and models for engaging in sustainable, scalable transformation.