Hi Cristian:
Students drift off or lose attention if they are bored, don't understand, are unprepared, or feel there is no benefit to them to pay attention. Iny activity that addresses one of these (if that's the reason) will help get them back on track.
Simple techniques like standing next to a student, asking questions ramdomly, or having a student clarify or restate the last point work well. Sometimes more aggressive measures are needed such as changing activities. Good ones that involve small group discussion, changing to a lab activity, or even moving back and forth between different activities are… >>>
