Generating questions is a regulatory action associated with self-monitoring processes in comprehension tasks: subjects can ask information seeking questions to solve comprehension obstacles. A sequence of two related experiments were conducted to trigger, classify and analyse questions asked under different conditions: reading a text about experimental scientific devices operating, watching these devices in a DVD and manipulating them in the LAB. Students' information seeking questions were classified using a simple taxonomy. Taking into account the multimedia learning principles, the advantages of realistic animations for understanding time-depending processes and the effect of the procedural-motor activity, were expected students would ask different questions under each of the aforementioned conditions. Results confirmed the expectations: the reading condition triggered more questions addressed to describe the entities while the watching and manipulation conditions stimulated more causal questions. In addition, the effect of prior knowledge on questions including scientific concepts was analyzed.