Technological failure as an epistemic resource for physics learning: A case study of DLP projector breakdown

Digital technologies are deeply integrated into contemporary physics education, although their malfunctions are typically treated as logistical problems rather than as phenomena for scientific investigation. This exploratory qualitative case study examined how 34 pre-service primary teachers explained the persistent white dots produced by a malfunctioning digital light processing (DLP) projector and how their explanations developed during a two-session inquiry- and model-based instructional sequence. Data were collected through structured observation and hypothesis-generation tasks, classroom discourse, model-construction activities, and final written explanations. Initially, participants commonly attributed the white dots to external or generic causes, including dust, defective pixels, image files, or signal problems. During the inquiry phase, observations showing that the dots remained fixed across changes in image content, input source, and the projector’s internal menu progressively constrained these explanations and directed attention toward an internal cause. During the model-based phase, simplified representations of the DLP optical pathway and micromirror array supported more explicit causal accounts linking immobilized micromirrors with the continuous direction of light toward the screen. The findings indicate a qualitative progression from phenomenological or generic fault descriptions toward more mechanistic explanations, although this development was not uniform across participants. The study does not establish the general effectiveness of inquiry- and model-based instruction; rather, it illustrates how a stable technological malfunction can provide a context for evidence-based hypothesis evaluation and causal model construction in physics learning.