This very thorough and professional program provides 'a means for students to self-check the results of calculations associated with some acid base and acid carbonate reactions'. It is designed so that the student who has difficulty in accurately rendering the calculations may be guided through the process in a structured way.

The student using Titrations needs to be familiar with molarity and the way in which it relates to concentration. It is recommended that the students have a calculator handy - I certainly needed one. They are presented with the choice of dealing with figures supplied by themselves from their own experimental data or of using computer-generated problems as revision and remedial material.

Two levels of difficulty are available and, after choosing, the pupil will be asked to calculate either a molarity or a volume. When errors occur, the machine branches into a HELP routine appropriate to the point in the equation that caused the difficulty. Continual failure to understand the help given results in the machine performing the calculation itself step-by-step, with the parts of the equation being operated highlighted. The program is patient, perceptive and persistent.

Although it is not very striking visually - it's all printed in cyan text on a black background - this perhaps underlines the serious intent of the program. It is designed to be used as a scientific tool and has no fancy frills. However, a print-out facility might have been useful so that the results, especially of pupils' own calculations and experiments, could have been taken away as hard copy.

Titrations is a robust and efficient program that uses the simple techniques of repetitive reinforcement to enable students to attain high standards of accuracy in their equations.