Exploration of troublesome and threshold concepts in cloud microphysics

We investigate the difficulties faced by undergraduate students during a four-hour cloud microphysics introductory lecture and aim to identify troublesome concepts. An open-ended survey was conducted after the lecture. Twenty-nine students answered five questions related to the concepts they were taught. Thematic analysis of the data resulted in a list of concepts related to the course content and their total counts from the survey. The analysis reveals that four properties could be extracted from the data: identifiability, novelty, difficulty, and importance. These properties are subsequently used to discuss potential threshold concepts in cloud microphysics. We also discuss the criticism that threshold concept theory is exposed to and motivate the necessity to develop a working definition of threshold concepts with a reduced set of properties that could uphold the discussion around their identification. Based on the results of the survey and a review of their geophysical structure, we find that “Homogeneous vs. heterogeneous nucleation”, “Subsaturation vs. supersaturation” and “Critical radius of a droplet” are prime threshold concept candidates. This study highlights the importance of considering the students’ perspectives and difficulties when investigating the nature of concepts in a specific discipline. It provides insights into the field of cloud physics education and informs the development of instructional material and teaching practices.