ABSTRACT
In the case of recursion, which I do not intend to labour further, I offered an analytical description of the variation in ways of understanding (or experiencing) the concept, pointed to critical differences between the three categories that comprise the description, and suggested ways in which those critical features could be subject to variation in teaching. The engineering educator needs first of all to identify the important knowledge, what has the threshold quality described earlier. In elementary calculus this could be integration which can be understood in many ways, and some are more fruitful for subsequently handling differential equations than others are. In environmental science it could be energy, which is a troublesome concept at the best of times but which takes on special significance in the closed systems of the environment (Carlsson, 1999). In many fields of engineering the notion of a model is problematic and students can confuse the model with the phenomenon that is being modelled, with consequences that vary from area to area. Such key concepts and principles as these are worthy of extra teaching effort in order to support students’ understanding across the field they are studying.
