Technical rephrasing

The activity:

Given a process or a technique, the students will be asked to draw a picture (if you want them to describe the apparatus) or to make a flow chart (if you want them to describe the process) before and after the lab session.

The "before" picture or flow chart can be part of a pop quiz at the very beginning of the session. The "after" can be completed right before the students leave the lab.

By making a schematic representation, the students will be forced to isolate the basic principles involved. Usually, the first representations are barely appropriate and reflect the gaps in the student's understanding of the material. After completion of the experiment and sufficient incubation time, the final representations are more accurate and include more operational details (such as water flow in cooling systems, lens magnification, etc).

This activity can be used as an evaluation tool when a particularly difficult new technique is introduced. It is better to do it individually, since in a collaborative effort it would be harder to evaluate the input of each student.