T. Kurucsev University of Adelaide Adelaide 5001, Australia
The Design of Laboratory Exercises A n analytical a p p r o a c h
A
student when assigned t o do a laboratory exercise might have either explicitly or implicitly three basic questions in mind What has t o be learnt? What has t o he done? Is it going to be interesting?
An answer in the affirmative t o the last of these questions is certainly of primary importance t o be achieved by the designer of the exercise. However, the problem of "relevance" is difficult to discuss in general terms since it depends on the circumstances; on the background and aspirations of the student body; on the local and temporal problems and prejudices of the teaching staff and societ,y in general. For this reason the subject matter of this article will be restricted largely t o the more formal aspects of the design and analysis of laboratory exercises. In particular, the outline of a general formalism will be given with the purpose of ensuring that precise and reassuring answers are received by students to the first two of the questions above. General Formalism
I n broad terms laboratory exercises serve the dual purpose of teaching or illustrating theoretical principles and of teaching technical skills. Students are then instructed what to do and how to do it in order t o achieve the above aims. Thus the concepts implied by the first two basic questions may be referred to as Aims or THEORY/SKILL Instructions or DO WHAT/HOW
The formalism suggested here is equivalent to arranging the above "units" in the form of a flowchart shown in Figure 1.
into a succession of iterations until the exercise becomes self-consistent. One might add that the possibility of taking DO WHAT rather than THEORY/ SKILL as the initial point of departure for the iterative proeess is not excluded. Construction of such aflowchart is considered t o have the following major advantages. First, critical evaluation of the exercise is readily achieved. The aims listed explicitly may be considered from the point of view of their importance, relevance and whether their number is sufficiently low to ensure that students absorb and digest the ideas presented and acquire the skills desired in the time allotted to the exercise. The close scrutiny of DO WHAT/HOW may suggest deletions, additions or alterations more in line with the stated aims. Secondly, the completed self-consistent chart would correspond to an ideal basis for the preparation of the presentation of the exercise to the students eommensurate with their abilities and background. The choice of presentation is in no way impaired by the existence of the flowchart, it is only made more conscious. For example, one might consider detailed and precise presentation of an exercise for freshmen, while for other groups educationally more advanced presentation of an intentionally less explicit form to encourage independence and thinking to a purpose might be more suitable. Either type of presentation u-ould profit since the flowchart would ensure that all aspects of the exercise were adequately accounted for. Thirdly, based on the final flowchart and perhaps using a somewhat similar format a detailed summary of the exercise may be prepared. Such an itemized indexing could be of considerable help to the students and in the construction and planning of the complete laboratory course. Examples
Figure 1. General block diogrom for the construction of flowcharts in the design and analysis of laboratory exerciser.
According to the flowchart the design of an exercise may begin by defining a set of bheoretical principles and practical skills that the students are expected to acquire. A set of experimental manipulations are then selected that serveas vehieles towards achieving the THEORY/ SKILL aims and they are itemized concisely but without omissions. At this point the feedback from the DO WHAT/HOW is examined t o see what modifications or amendments of the original THEORY/SI
