Physics has greatly impacted society, both in solving problems and perpetuating harm, yet we rarely train physics students to grapple with their responsibilities to society. The absence of direct discussions about the intersections of science and society in classrooms reinforces the idea that physics is purely objective and removed from societal impact or influence. In work done at Texas State University, we designed and implemented units about ethics, science and society in three different contexts: a modern physics course, an observational astrophysics course, and a multi-disciplinary course entirely focused on this topic. In each of these contexts, we scaffolded student discussions around large-scale ethical issues related to STEM. This talk will draw on my experiences participating in this work as an instructor and a researcher, to highlight factors that enable and limit student engagement and consider implications for instruction.