Developed in conjunction with the BBC Schools Television Science Topics series, this package consists of a suit of programs supplied on two 40-track single-sided discs. Wave propagation and reflection and dealt with on one disc; reflection, interference and diffraction on the other.

A 40-to-80 track conversion program is included, but a 40 track drive is still required to make the initial backup of the original discs. With this available, we found no difficulty copying both discs onto the two sides of an 80-track disc and then modifying the menu to access both sides.

Waves illustrates most of the wave properties that can be demonstrated on a school ripple tank and is best considered as a supplement to this rather than a substitute. The package is designed with the emphasis on simplicity. Parameters such as wave speed, wavelength and angle of incidence are chosen by single keystrokes from a menu or by using the function keys.

The animated graphics are bold and straightforward - wavefronts are shown as white lines on coloured backgrounds with different backgrounds for various wave speeds. Close up the animation is irritatingly jerky, but on stepping back from the monitor I discovered that, with the exception of the green background used for the slowest wave speed, the display was easily visible from the back of the classroom and movement appeared quite smooth.

Other choices available are: plane or circular wavefronts, plane or curved reflecting surfaces (reflection), plane or curved medium boundaries (refraction), wavelength and slit separation (interference), and slit width (diffraction). There are several facilities including the ability to freeze and to single-step the wave motion.

There is also a facility to print the screen on an Epson printer. This is a wonderful idea to anyone who has ever had to draw an interference pattern by hand, but why does the screen dump insist on sending both a CR and LF at the end of each graphics line? The inclusion of the line feed requires that the Epson's response to this character be switched off at the printer to avoid double spacing.

Refraction is always difficult to demonstrate convincingly with a ripple tank and this is one area where the package can usefully fill some gaps. I was especially impressed with the ability to exceed the critical angle and to show the onset of total internal reflection. On the other hand, it's a pity that the program cannot cater for a pair of medium boundaries to demonstrate prisms and lenses.

Put to the classroom test, this well-documented package proved to be one of the few computer teaching aids that really works, where the micro becomes an efficient but unobtrusive tool.