Where's the Line? A Classroom Activity on Ethical and Constructive Use of Generative AI in Physics

Generative AI tools like ChatGPT are rapidly reshaping how students and instructors engage with course material-and how they think about academic integrity. This paper presents a classroom activity designed to help physics students critically examine the ethical and educational implications of using AI in coursework. Through a structured sequence of case analysis, discussion, and optional policy drafting, students develop the metacognitive, ethical, and collaborative skills needed to navigate emerging technologies with thoughtfulness and integrity. Grounded in research on constructivist learning, metacognition, and student agency, the activity positions students as co-creators of an ethical and engaged learning environment.