The purpose of this study is to describe the conditions under which diffracting noticing becomes both a process and product in dynamic relations to re-imagine preservice science teachers' becoming as ethical mattering, a concept rooted in a relational ontology of change and emergence. Drawing on theories of posthumanism, this study theorized pre-service teachers' "becomings" as ethical mattering which pays attention to two events: 1) the differences produced when participants engage in diffracting noticing by placing themselves in the middle of where they are in their "becomings," and 2) the effects or a material mark on bodies, things, and other actants left by these differences. During these events, intra-action and entanglement with other actors produced differences and juxtapositions about how they understood and enacted equitable science teaching. Preservice teachers began to re-imagine what they would do differently to enact more equitable and inclusive teaching practices. Preservice teachers who participated in diffracting noticing could "see" their teaching practices in relation to and entangled with others, and therefore became differently and ethically mattered. In doing so, teachers rendered themselves and each other response-able and accountable for the knowledge that was collectively co-constructed about equitable teaching. The notion of becoming as ethical mattering illustrated in this study contributes to a new thought and re-imagines the traditional notion of change-in-practice, as preservice teachers could not be the same person as they were prior to intra-acting and thus seeing-becoming differently.