Classical attempts at interpreting the photoelectric effect – Part 1: the hypotheses of Philipp Lenard, Arthur Haas and J.J. Thomson

Recent studies have renewed efforts to draw attention to the pseudo-historical narrative describing Philipp Lenard’s experimental results on the photoelectric effect as inexplicable and inconsistent with predictions of classical wave-electromagnetic theory. However, in examining the transition period between the rejection and acceptance of Albert Einstein’s “quantum of light hypothesis”, at least six classical attempts to interpret the photoelectric effect can be identified, rarely discussed in textbooks or academic texts. In this first article of a three-part series, four classical hypotheses on how the photoelectric effect is produced are presented, formulated respectively by Philipp Lenard (one), Arthur E. Haas (one), and by Joseph J. Thomson (two). The findings provide insights for teachers and students to explore conceptual, procedural, and epistemological aspects in the context of the early development of quantum theory, from a problematizing and historical perspective on scientific activity.