Adopting a sociocultural perspective, we construct a case study exploring how a middle school bilingual science teacher reflected and acted when engaged in dialogue, co-teaching, and a newly designed unit on plate tectonics. Sources of data include video of classroom interaction and audio recordings of daily debriefs between the bilingual science teacher and second author. Dialogic reflections between these individuals reveal how the new curriculum, the dialogue, and co-teaching with the second author mediated the teacher's emerging abilities to think and act in different ways at that sociohistorical moment in time. Based on these findings, we highly encourage professional development experiences to include ongoing dialogic reflection and co-teaching to "shake" teachers' views and practice. These initial connections can indicate inroads into helping teachers broaden understanding of bilingual science education.