Development of a new teaching-learning sequence on the particulate nature of matter using crystal structures

When learning about the particulate nature of matter (PNM), students tend to attribute the same properties to both particles and to the substances they compose. It has been argued that this might be explained by them categorizing the wrong ontological category. To explain the relationships between submicroscopic and macroscopic levels of matter, students need to understand the concept of emergence. Building on prior work, the authors propose that crystal structures might be a suitable context for the introduction of the PNM. As there is a close connection between the behavior of the particles and the properties of crystals, students can learn the concept of emergence and therefore gain a deeper understanding of the PNM. This study investigates students’ learning about the PNM within the context of crystal structures following the methodological framework of design-based research. The aim of the study is the development of a prototypical teaching-learning sequence (TLS) on the PNM and to help developing local theories for teaching that subject. Throughout several cycles of designing and refining the TLS, a total of 40 interviews were conducted using the method of probing acceptance. Evaluative qualitative content analysis led to new insights into students’ thinking about the PNM and allowed for further development of the TLS. For example, we found that salt and snow crystals were a more effective learning context than a scanning tunnel microscopy image of graphite for students to come to understand the connection between macroscopic and submicroscopic levels of matter.