Experiences with an instructional strategy which enabled students to build for themselves the appropriate scientific concept for energy are described. This was done by pupil/teacher dialogue in small groups, in which students were expected to create for themselves a "generalization mechanism" based on their own frameworks. (KR)

Three experiments using university students explored what constitutes an event and what determines its boundaries. Results supported the hypothesis that sequences of stimuli repeating in different contexts are cut out to become cognitive entities ("things" with a beginning and an end) in their own right. Results suggest that the…