**4. Non-experimental experiential activities**

It is worth completing this discussion with a brief explanation of experiential activities that can be performed in a theory class. Remembering that experiential learning requires reflecting, thinking, and acting after an experience, a common activity employed by an educator is a thinking experiment. This requires the students to imagine a particular unit operation, and think about how it might work. Others might include practical demonstrations, real-life scenarios, or "story-telling" particularly in the form of analogies, which enables the learners to access the complexities of a topic using more familiar situations.

The author has previously introduced a very successful thinking experiment into ChE417: Separation Processes, at UM on fixed bed adsorbers. This is preceded by a theory lesson outlining the basic terminology of adsorption processes, typical adsorbents, and applications, followed by the various adsorption isotherms commonly discussed in the literature. This helps to build knowledge and creates an "experience" (although theoretical) of how adsorbers work and their typical applications. The thinking experiment begins in the following class, where the students are asked to think about how the concentration of solute in the fluid would vary as it travels over the length of a fixed bed adsorber. They draw their thoughts on a concentration vs. length graph. This is followed by a class discussion on mass transfer zones, and then students are asked to think about whether a narrow or wide mass transfer zone is better, with justification. They then need to discuss in groups what types of factors might affect the length and the rate of movement of this mass transfer zone, and are challenged to come up with at least 10 different factors. The thinking experiment continues where students are asked to draw on a concentration vs. time graph what the breakthrough situation may look like. With further discussion, they come to the realization that integrating such a curve will represent the amount of solute adsorbed for a given time. This exercise is highly engaging for the students, and enables them to fully "experience" the workings of a fixed bed adsorber, with considerable reflection and cognitive developmental opportunities. Acting on this new knowledge is subsequently gained with calculation questions for fixed bed adsorber design.

This straightforward example of presenting content in a highly engaging way demonstrates how a unit operations "experiment" can still be conducted effectively within a theory class. This type of teaching and learning is particularly suited to smaller colleges where equipment and funding may be minimal. Studies have shown that experiential learning activities such as the one described are only marginally less successful than an actual experimental program [36]. If the experimental programs are not carefully developed as outlined earlier in this chapter, then the net gain of experiential learning *via* experiment is reduced, and active learning activities within a theory class can be equally or more beneficial.
