Alternative conceptions in Galilean relativity: distance, time, energy and laws

This work, a sequel to Panse et al. (1994), focuses on how students deal with transformations of time, distance, velocity and energy between frames of reference. Qualitative analysis of a free‐response test and of clinical interviews is combined with quantitative analysis of data on a forced‐option test. The results indicate that students frequently violate the ‘obvious’ invariance of time interval between fixed events, and take distance invariance for granted even for non‐simultaneous events. They tend to invoke a ‘physical drag’ picture instead of prescriptive transformation theory to view changes of quantities (especially velocity) from one frame to another. The diffuse meaning of ‘laws’ shows up variously. Laws are equated to trajectories; and conservation of energy is taken to mean its invariance, for observers, in relative motion.