We present a study of a first step in a large-scale intervention designed to shift lab instruction away from highly prescribed lab norms. The intervention was implemented in a national network of Professional Learning Communities of high school physics teachers (N=250) operating in a high-stakes exam setting with limited resources, and catering to diverse groups of students. A pre-intervention survey examined learning goals that the teachers value as well as practices taking place in their lab lessons. The findings revealed a gap between the importance that teachers attributed to scientific practices such as experimental design and the manifestation of these goals in the national lab exam. In addition, the survey revealed disparities between the scientific practices that teachers believe that their students engage in during the instructional lab and the practices they identify in physicists' work in research labs. The intervention consisted of a series of Restricted Inquiry Labs (RILs) designed to address the teachers' interest in change as well as the constraints imposed by the setting in which they work by modest restructuring of traditional labs such as encouraging students to reflect on the considerations underlying the experimental design. The intervention proved successful in that half of the teachers reported that they introduced the RILs. They described students' engagement when granted more autonomy in designing an experiment, as well as students' difficulties in coping with a more open-ended task. Implementation of the RILs also created challenges in class management. Despite these challenges, most teachers reported that they intended to keep using RILs. Teachers asked to redesign assessment policies to emphasize scientific inquiry. The RILs proved to be a feasible way to introduce change towards inquiryoriented labs via professional development programs, while pointing out aspects that need to be addressed to respond to teachers' concerns.

The instructional lab setting has been found to be dominated by prescribed tasks and pre-prepared lab kits. This was explained by teachers’ need to guide students to simultaneously progress through a lab curriculum, which prompts them to standardize the lab experience. Nevertheless, prominent professional associations have persistently called to better represent experimental research practices in the lab, and to grant students more agency in the experimental process by orienting them towards more open-ended lab experiences. This paper reports a lab activity designed to advance students’ agency in the practice of experimental design, in a setting governed by a high-stakes national matriculation exam. Three hundred teachers of advanced level high-school physics experienced the lab activity in a national network of professional learning communities (PLCs). The activity was anchored in an experiment to determine the relationship between the current through a battery and its terminal voltage. It was designed to problematize students’ considerations underlying the choices of the location of the voltmeter and the measuring scale of the ammeter, and the possible implications for the validity of the experimental results; e.g. control of the variables, as well as the range and the accuracy of measurements. Teachers first performed the lab activity as learners, discussed it in the PLC meeting, and finally reflected on their experience. Individual responses to the lab worksheets and the reflections were analyzed. Initially, teachers’ considerations did not portray key aspects related to the validity of the experimental results, such as how design choices related to the location of the voltmeter and the ammeter measuring scale impacted the accuracy and range of the measurements and the control of variables. The teachers were highly engaged in the peer discussion in the PLC and found the lab activity valuable in raising students’ awareness of important considerations in experimental design.