When Dorling Kindersley brings out a new version of its general science CD-Rom, then it must be a measure of past success. It’s a measure of need too - the idea of covering the three sciences and maths as well on one disc is irresistible in teaching as well as the home-learning market.

This Encyclopaedia is a broad sweep - the second version has 1,000 more articles, which is nearly 10 times the material of the original CD-Rom. There’s a Matter Explorer which lets you take either a leaf, aphid, metal or a nylon sock and magnify it stepwise till all you see is atoms. That’s good. So are the handy bits of animation showing electrolysis, gases diffusing, coloured light mixing and meiosis - the making of sex cells.

There is extra detail, although these new articles don’t explain, say, antibodies, the red shift or reaction rates very well - you’ll find better explanations in school books. But now and then the pictures or the video of - for example, bacteria dividing - add value.

What is unmatched, however, is how easy this CD-Rom is to use - a menu shows the contents as a branching tree, so you soon see what it covers. Buttons called “see also” and “find out more” keep feeding your curiosity. The film index may show tiny pictures and the main menu may be a retro-look museum console, which seems like gimmickry, but if that appeals to children, well that’s fine. All the text is now searchable, printable and copiable to a PC.

The title is, I think, unfortunate, simply because it promises too much. If you look at the CD-Rom as a course book, it shows gaping holes. Interestingly, a button connects you to Dorling Kindersley’s Science On-line place on the Internet, a feature that may one day plug all the gaps.