An Inquiry-based approach to the Franck-Hertz experiment

In this study we present the results of an inquiry-driven learning path experienced by a sample of 15 selected engineering undergraduates engaged to perform the Franck-Hertz experiment. Before being involved in this experimental activity, the students received a traditional lecture-based instruction on the fundamental concepts of quantum mechanics. Despite the instructor’s introduction to specific technological/engineering-based contents during the course, the students’ answers to an open-ended questionnaire, administered at the end of the lectures, demonstrated that the acquired knowledge was characterized by a strictly theoretical vision of quantum science, basically in terms of an artificial mathematical framework having very poor connections with the real world. This could be ascribed to the many difficulties that students demonstrated to have in order to deal with concepts at scales in which they cannot have a direct experience in their everyday life, especially at microscopic and sub-microscopic scales. In order to fulfil these lacks, the students were invited to actively participate to an experimental activity within an inquiry-based learning environment at the Laboratory of Condensed Matter Physics at the Department of Physics and Chemistry of the University of Palermo. The Franck- Hertz experiment was introduced to the students by starting from the problem of finding an experimental confirmation of the Bohr’s postulates asserting that atoms can absorb energy only in quantum portions. By following the lines of a scientific inquiry, the students, working in group, performed a questioning activity that naturally guided them throughout the steps of the Franck- Hertz experiment.