CAUT Report

UniServe Science News Volume 8 November 1997


Application of Explanation Based Learning to the Teaching of Biochemical Calculations

Gareth Denyer
Department of Chemistry, The University of Sydney

The Problem

Enter any Biochemistry Department tea room in the world and you're likely to hear the question. "Why do so many Biochemistry students have problems with chemical calculations?". What's surprising is that the mathematics and concepts involved are as simple as those used to calculate a restaurant bill. Indeed, we think that the reason for the problem is that students treat biochemical calculations as abstract and, instead of trying to visualise the question and develop problem solving strategies, they rely on rote-learned formulae. As a result, they never develop any confidence in calculation techniques, and therefore are never in a position to judge if an answer is sensible.

The Solution

We wanted to design computer-based calculations guides containing animations which would enable students to visualise questions and appreciate the process by which data are obtained. We reasoned that such an approach would give students experience at reducing a seemingly long, complicated written question into a simple picture from which numbers can be hung. We planned to include as much interaction as possible so that we could teach a problem solving strategy, build confidence, and give real-time formative feedback.


Before development even started, we set up regular group discussions with tutors, students and programmers. Indeed, the project evolved in response to students' requirements.

In our original application, we asked for funds to pay an outside developer to construct the software. However, it soon became clear that, if the students were to be involved in the development of the modules, then the 'programmer' should be a competent teacher of biochemical calculations. Such is the ease with which multimedia programs can be developed using modern software (we used Authorware) that, in our opinion, a computer-literate Biochemist can produce Biochemical programs more efficiently than a non-Biochemist multimedia guru. In fact, our job as project leaders was made much easier by the fact that we did not have to explain the needs of the students to a non-biochemist programmer.

The Product

Four separate modules were developed: Buffers, Radioactivity, Spectrophotometry and Step-Wise Calculations.

Diagram 1

Tutorial sections extensively use animation and analogies to teach key issues. This picture is built up over several screens, each of which uses graphics and movement.

There are also a number of interactive examples that the student can work through. Again, animated sequences are shown to aid the student's visualisation of each problem.

Diagram 2

Some of the modules provide simulations which give students the opportunity to see the consequences of altering the composition of a buffer.

Finally, each module contains a number of interactive quiz questions. If the student is unclear about the strategy to approach a question or how to reach the answer at any stage of each calculation, they can request on-line help.


The programs have been well received by the students and have been used in the teaching of Biochemistry courses both here and overseas. However, although it was hoped that, by presenting the subject in an animated and dynamic manner, the computer would mimic the teaching style used by a tutor, we feel that we are a long way from a situation in which the computer genuinely interacts with the student and actually seeks to ascertain why a student made a particular mistake.

So, as well as allowing us to produce some software of which we are reasonably proud, the CAUT experience has taught us that the words shown on our computer lab walls still ring true, "If your tutor can be replaced by a computer, they should be replaced by a teacher".


The tutorials have been made available free of charge for both Mac and DOS platforms on the WWW at


We were indebted to the expert and enthusiastic development skills of Elke Wiseman in completing this project.

The grant for this project was awarded to Gareth Denyer and Jill Johnston, Department of Biochemistry, The University of Sydney.

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UniServe Science News Volume 8 November 1997

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