One of the stated aims of this programme is, "To assist the teacher in supplying self help materials and remedial exercises to individual teachers." It achieves this very well indeed. The authors do not claim that this programme will teach the calculations associated with elementary tltrations - that Is the teacher's job. The programme has two options. Firstly acting as a calculator to check the pupil's answer from an actual experiment. What is wrong with answer cards or asking the teacher I hear you asking? Well, if the answer is incorrect the pupil is offered the option of trying again or working through the program step by step. The steps are: calculating the number of moles of the standard solution, identifying the mole ratio from the equation, Identifying the number of moles of the unknown and thence calculating the concentration of the unknown.

The second option can present in excess of 300 problems on acid-base and acid-carbonate titrations at two levels of difficulty. The easy problems have 1:1 mole ratios with molarity the unknown quantity and the harder problems have 2:1 mole ratios and may have volume as the unknown. The problems use either hydrochloric acid or sulphuric acid and either sodium hydroxide or sodium carbonate. This is sound pedagogy when used as a remedial exercise not a limitation. It Is possible for the user to make a dozen mistakes before the machine's patience is exhausted and it provides the answer.

The program is easy to use with clear instructions on the screen for the pupil and clear, concise notes for the teacher. These notes give details of the range of answers accepted and the range of values of volume and molarity. The program runs in Mode 6 and is therefore Visually bland.

The second aim of the program is, "To assist in the diagnosis of difficulties encountered by students..." I would have liked to have seen a record maintained of the pupils' progress, the number of mistakes made and where the mistakes were made. This would provide a truly diagnostic tool. As it stands there is no feedback to the teacher and its diagnostic function is limited.

However it is still a very useful program suited to any course involving elementary titrations, but at £14.95 a bit pricey.

Dave Reeder