This chapter takes up the feminist new materialist concepts of “diffraction” and “intra-action” as ways of thinking about children’s embodied and imaginative knowledge through, and in relation to, aspects of the world that can be classified as the non-human. It employs these new materialist frames of “diffraction” and “intra-action” to show how art/science intra-act through “quiet activism” in children’s art. It argues that this work can be considered a vernacular form of STEAM education that radically re-situates, and indeed deconstructs, forms of science education proposed through outcomes-based curriculum, and extends children’s sense of themselves as entangled in their environment. The data theorised in this chapter is drawn from findings from a multi-sited ethnographic project that runs in 13 sites in 6 cities. This ongoing empirical project utilises art as a research method in primary school classrooms and informal educational settings, ostensibly to explore issues of social value and community belonging. However, across the last three years working in the UK and Australia, children, unprompted, have returned repeatedly to concerns about the environment, climate change and pollution. The children are so enmeshed in their broader environment that some draw self-portraits of themselves as landscapes. The arts-making practices reported here have led children to create speculative and imaginative scientific inventions that were designed to respond to the now inevitable effects of climate change and that merge art and science in unexpected ways. In developing the concept of quiet activism as an inherently interdisciplinary art/science (STEAM) method of environmental and art education, this chapter argues for an intra-active and diffractive, interdisciplinary and speculative model of embodied pedagogy. Children’s creative, quiet activism teaches us interdisciplinarity in dynamic and applied ways.