Learning processes will be analysed as “evolution of student’s ideas” or as “conceptual change” on a timescale of several hours. The idea is to follow a single student’s constructions “during” the whole process of learning in more detail, including analyses of learning effects. The paper in part two discusses theoretical and methodological issues of such learning process studies. Here, the focus is on the unit of analysis (expressed ideas or conceptions) and on the relation between teaching and learning. In part three, a more recent study about the evolution of students’ ideas about gases is presented, describing learning by using three categories: A student expresses a new idea, a student increases the domain of validity of an idea, or a student establishes a link between several ideas and develops a network. In part four, another more recent study about analysing learning effects of the learning environment on single students learning is presented. Here, different types of resonances are used as categories, e.g. congruent or disgruent resonance, spontaneous or retarded resonance. Both studies come to grounded hypotheses how to improve teaching. In part five, more general issues about learning process studies are discussed.