In this paper, we report about designing and validating a teaching learning module based on a learning progression and focused on the causes of seasons. An initial learning progression about the Celestial Motion big idea —causes of seasons, lunar and solar eclipse and Moon phases— was developed and validated. Existing curricula, research studies on alternative conceptions about these phenomena,
and students’ answers to an open questionnaire were the starting point to develop initial learning progressions; then, a two-tier multiple-choice questionnaire was designed to validate and improve it. The questionnaire was submitted to about 300 secondary-school students whose answers were used to revise the hypothesized learning progressions. This improved version of the learning progression was used to design a module focused on the causes of seasons in which students were engaged in quantitative measurements with a photovoltaic panel to explain changes of the Sun rays’ flow on the Earth’s surface over the year. The efficacy of our module in improving students’ understanding of the phenomenon of the seasons was tested using our questionnaire as pre- and post-test
