The Next Generation Science Standards (NGSS) [Achieve, Inc. []] represent a broad consensus that teaching and learning expectations must change. Rather than memorizing and reciting information, students are now expected to engage in science practices to develop a deep understanding of core science ideas. While we want to share in the optimism about NGSS, the standards are not a silver bullet for transforming science classrooms. They are, instead, another reform document designed to suggest opportunities for students to actively engage in knowledge construction themselves—to be doers of science, rather than receivers of facts. A foundational contradiction underlies these efforts—while we want students to do science, we seem to mean that students should mimic practices others have selected as important to learn, and content others have selected as foundational. As a result, students are rarely positioned with epistemic agency: the power to shape the knowledge production and practices of a community [Stroupe [] Science Education 98:487–516]. We argue that unless the field tackles significant questions around precisely how students can be active agents in knowledge construction, we will likely continue to implement learning environments that position students as receivers of scientific facts and practices, even as classrooms adopt NGSS. In this conceptual analysis article, we unpack the construct of “epistemic agency” and its relationship to the NGSS, using a vignette to illustrate how students are typically positioned in researcher‐developed curricula. The vignette, which describes a seventh‐grade class exploring which of two lakes is more at risk for invasion by the spiny water flea, provides an exemplar of what we take to be a loose consensus about learning environments consistent with the NGSS. However, when we look beneath the surface of the consensus, the vignette reveals contradictions and unresolved issues around epistemic agency.

Science educators increasingly seek to support students' participation in scientific practices, particularly epistemic practices, that is, those that ground authority for knowing in the discipline. Argumentation is one practice that has received significant attention in the research literature. However, scholars who take a sociocultural stance increasingly suggest that current conceptualizations are not sufficient for characterizing and supporting important aspects of scientific practice. In this article, I explore how students' argumentation can be brought into closer alignment with that of scientists. I identify consequential differences in the contexts in which scientists and students typically enact argumentation and discuss how these differences have been addressed in the literature. Finally, I propose several directions for further research: embedding argumentation in uncertain scientific activity, supporting students to contest both what they know and their means of knowing, building more carefully from students' resources, and attending to the development of epistemic cultures in classrooms.

This article addresses how we can develop learning environments that establish a need for scientific practices and provide a context for developing content knowledge through practice. It argues that Pickering's (1995) notion of "The Mangle of Practice" informs these efforts by focusing our attention on how resistance, or push-back from the world, destabilizes practices and ideas, creating a need to re-evaluate each in light of the other. I describe the design of science instruction for an elementary school classroom, showing how it built from attention to the mangle and established principles in the fields of education and the learning sciences. I then explore how three forms of activity emerged, were taken up by students, and developed as practices in the classroom community. Implications for the design of learning environments include attending to why students engage in practices and building resistances into students' work to support the co-development of practices and content understandings.