There's no secret formula for writing successful science textbooks. But there are some simple guidelines for spotting likely winners. Geoff Hayward sees how four series for modular A-level courses measure up
What makes a good science textbook? There are three criteria by which most can be judged: clarity of text, effectiveness of graphics, and variety of questions.
Scientific English is based on three key genres: report, explanation and experiment. To become science-literate, A-level students need to be introduced systematically to this trio, mastering the "grammar" of the subject, rather than simply learning a long list of technical terms.
A picture may be worth a thousand words, but diagrams, photographs, charts and tables require considerable thought to extract meaning. Graphics must therefore complement the text to assist understanding.
And what about questions? A good textbook should contain a variety of question types, especially those that draw students' attention to key ideas and help them synthesise information. Weaker texts will emphasise simpler, "closed" questions that can be answered by scanning and copying from, rather than reading and interpreting the text.
HEINEMANN ADVANCED SCIENCE
These books score well on text and questions, but less so on graphics. The two most recently published, Particle Physics and Human Health and Disease, contain well-written examples of all three science genres plus extras such as biographies of Sir Ernest Rutherford and Paul Dirac.
Particle Physics combines a strong emphasis on the historical development of the subject with good explanations of complex ideas such as quantum electro-dynamics. Human Health and Disease is less convincing in places, with overwhelming amounts of information presented as continuous prose. Help will be needed to make sense of it all.
Both titles use boxes effectively to highlight major points. However, graphics are not integrated properly; many are not even referred to in the text. This is a shame, as the quality of the diagrams is good. For example, in Particle Physics the image of a sailor striding from boat to boat, as an analogy to explain forces of interactions between particles, is a sound idea, but needs explaining in the text. Each chapter concludes with a summary of the key ideas and, in the case of Particle Physics, a good range of questions to answer.
Heinemann Tel: 01865 314320. pound;11.50 each.
NELSON ADVANCED MODULAR SCIENCE
The physics texts in this series consist of precise, textually dense explanations interspersed with practical work. The text too often uses lists instead of developing the explanation and reporting genres. This occasionally makes the explanations difficult to follow; they will require considerable mediation by the teacher for all but the most able students.
These are useful reference books containing helpful examples and well embedded graphical material. There is a good range of practice and examination questions at the end of each text plus a glossary of key terms.
The chemistry and biology books score well on text, but must be marked down on integrated graphics and questions. The writing is of a good standard throughout, though the style of reporting varies considerably, with bulleted lists in places and more continuous prose in others. Definitions are highlighted in coloured boxes in the text margin.
Illustrations and tables are good, but too often they are simply referred to in the text with litle explanation. For example, what use are students to make of a table of selected standard reduction potentials that occupies a whole page in the chapter on redox equilibria?
There are margin questions dotted about, and exam questions at the end. Some of the margin questions are excellent, requiring students to read the text carefully. However, they are sporadic. For example, the chapter on heterotrophic nutrition has no questions, while the chapter on redox equilibria offers 12.
Nelson Tel: 01264 342992. Nine titles pound;9.99 - pound;12.99 each.
CAMBRIDGE MODULAR SCIENCE
Human Health and Disease and Methods of Analysis and Detection score well on all three criteria. Text is easy to read and well structured without sacrificing the emphasis on reporting and explaining. Occasional sections of text, or even whole chapters, for example on immunity, present more of a problem when a complex series of events needs to be explained.
This is partly due to the design, which involves the reader continually having to flick back and forth over several pages between text and diagrams. The diagrams are often well embedded in the text, especially in Methods of Analysis and Detection. Key features of, say, an infra-red spectrum are highlighted, or students are asked questions about a diagram.
Both books score well on the number and type of questions. Questions at the end of the chapters help to synthesise information, supported by a summary, though occasionally they lapse into a "describe X" format which is likely to produce answers that simply involve copying.
Cambridge University Press Tel: 01223 325588. pound;7.50 each.
COLLINS ADVANCED MODULAR SCIENCE
This series also scores well against all three criteria. The text is well written and engages the reader, without sacrificing the emphasis on reporting and explanation. It is presented in manageable units with regular groups of questions that require students to process the text rather than simply scan it.
Graphical material is well integrated, either by being used to answer questions, for example about fertilisers and plant yield, or forming an integral part of the text, as in the explanation of frames of reference in the chapter on Einstein.
There is a wide range of questions that help students to record essential information and develop their ideas. Answers to the questions are given at the end of the book. Some attempt to encourage synthesis and summary of ideas would have been useful at the end of the chapters. Key ideas are, however, regularly summarised and each text gives a real feel of what the subject is actually about.
My only major reservation is the design, which in some places makes the pages look messy.
Collins Tel: 0181 741 7070. pound;13.75 and pound;14.50 each.
Dr Geoff Hayward is a lecturer in educational studies at the University of Oxford