Can old quantum theoretical description of physics be rendered coherent? : A pilot experimentation for high schools

While many models of the Old Quantum Theory (OQT) have long been incorporated into international school curricula and textbooks, research in Physics Education regarding effective educational approaches to the OQT is predominantly centred only on individual topics (mainly black-body spectrum, photoelectric effect, and Bohr's atomic model), leaving a notable lack in providing a coordinated and comprehensive pedagogical, historical, and conceptual presentation that encompasses the entirety of the OQT. The following research questions thus arise: can the OQT be presented coherently and meaningfully without substantial alterations to prerequisites, topics presented, mathematical formalism, and time usually devoted at school, deepening the physics contents and making it effective from an educational point of view? What are the several disciplinary and learning knots of the OQT? Addressing these research questions, this paper explores the design, implementation, and testing of three extracurricular educational workshops focused on the OQT and conducted in 2022-23 and 2023-24 by the Physics Education research group of the University of Milan, with 210 high-school students and 93 teachers. Meetings included commented readings of original papers, collaborative group works with active understanding, and several qualitative and quantitative assessments and examples. Results obtained are here reported and discussed.