and Outreach (www.ceeo.tufts.edu). Merredith received all four of her degrees from Tufts (B.A. English, B.S. Mechanical Engineering, M.A. Education, PhD in Engineering Education). Her research interests focus on how children engage in designing and constructing solutions to engineering design problems and evaluating students' design artifacts. Her outreach work focuses on creating resources for K-12 educators to support engineering education in the classroom. She is also the founder of STOMP (stompnetwork.org), and LEGOengineering.com (legoengineering.com).

is a PhD student in STEM Education at Tufts University. Karen served as the Director of Research and Innovation at the science center CuriOdyssey and the Education Director of the Palo Alto Junior Museum and Zoo after teaching elementary and middle school. Her research focuses on elementary students' reasoning and decision-making in collaborative engineering design.

Background: Despite the prevalence and potential of K-12 engineering outreach programs, the moment-to-moment dynamics of outreach educators' facilitation of engineering learning experiences are understudied. There is a need to identify outreach educators' teaching moves and to explore the implications of these moves. Purpose/Hypothesis: We offer a preliminary framework for characterizing engineering outreach educators' teaching moves in relation to principles of ambitious instruction. This study describes outreach educators' teaching moves and identifies learning opportunities afforded by these moves.Design/Method: Through discourse analysis of video recordings of a university-led engineering outreach program, we identified teaching moves of novice engineering outreach educators in interaction with elementary student design teams. We considered 18 outreach educators' teaching moves through a lens of ambitious instruction.Results: In small group interactions, outreach educators used ambitious, conservative, and inclusive teaching moves. These novice educators utilized talk moves that centered students' ideas and agency. Ambitious moves included two novel teaching moves: design check-ins and revoicing tangible manifestations of students' ideas. Ambitious moves offered students opportunities to engage in engineering design. Conservative moves provided opportunities for students to make technical and affective progress, and to experience engineering norms.Conclusions: Our work is formative in describing engineering outreach educators' teaching moves and points to outreach educators' capability in using ambitious moves. Ambitious engineering instruction may be a useful framework for designing engineering outreach to support students' participation and progress in engineering design. Additionally, conservative teaching moves, typically considered constraining, may support productive student affect and engagement in engineering design.

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