SUMMARY
Background: Research concerning teachers’ professional learning in lesson study has been highlighted in Physics teaching; however, studies that examine this process from the elaboration of inquiry tasks are still scarce. This kind of task makes it possible to explore physical concepts and relationships due to their open nature, which contemplates the students’ interest, involves a practical dimension, and promotes successful learning situations. Objectives: To understand Physics teachers’ professional learning in planning inquiry tasks to study Ohm’s Law. Design: The investigation, of a qualitative and interpretive nature, involved 18 meetings of 2.5 hours. Setting and Participants: The lesson study engaged four secondary public school Physics teachers from the state education network. Data collection and analysis: The empirical research material consists of data produced in the development of the inquiry tasks, the transcripts of the audio recordings of the lesson study sessions, the investigative lesson, the material produced by the students, and the transcripts of the interviews carried out at the end of the lesson study. Results: The analysis showed professional learning about the development of inquiry tasks, analysis, argument, and inference of scientific knowledge, passing through engaging, exploring, explaining, elaborating, and evaluating activities on physical concepts. Conclusions: The research contributes to the knowledge development about teachers’ professional learning, especially about the research lesson.