Table of contents

Honorary Editor

Readers should now be fully aware that both The Institute of Physics and the Association for Science Education (ASE) are encouraging members to think hard about what they would like to see in the revised National Curriculum for science. The story of curriculum development in science for the past ten years has been of grand national initiatives which have concentrated, in science at least, on the content of what is taught rather than on the ways in which it might be taught - or how it is learnt. The initiatives have been `top-down', with usually rather hurried `consultation' with no attempt to weigh the value of responses. For example, in deciding upon a common core for A-level physics the Institute of Biology was given as much weighting as the Institute of Physics. What students thought seemed to be irrelevant. But chickens come home to roost, horses led to water don't always drink, and it seems that compelling all children to study physics as part of a science course has not had the effect of making them fall in love with subject and opt to study more of it after age 16.

Physics is a growing subject, in terms of what it now covers, as the increase in the number of journal titles over recent years shows. These show that it is also more and more a fragmented subject, and the practitioners of different fragments will have different views on what constitutes a foundation core for further studies. And, of course, fewer than 10% of students at one educational level choose to take the subject in the next. I conclude from this that what physics young people study between age 11 and age 16 doesn't matter as much as the writers of the National Curriculum supposed. We would like to get young people interested in physics (or better, interested by physics) and to develop positive feelings about physics and what physicists do, based on a feeling of success in studying the subject. Different students should be given opportunities to gain satisfaction in different ways; some via linking physics to everyday life, some via the way real people have developed and are developing the ideas and artefacts of physics and technology, some via the sheer pleasure of handling difficult ideas and mathematical models. And so on.

It may be that we should start looking at the outcomes of a physics course less (or not only) in terms of the knowledge and understanding that examinations test but also in terms of what the students think and feel about the time they have spent at our disposal. I suggest that a successful physics course should have the following certifiable outcomes for all students (within reason!), who should be able to say, as a minimum:

1. I enjoyed learning physics.

2. I understood quite a lot of it.

3. I can use my understanding of physics to make some sense of the way things are and how things work.

4. I could learn more physics if I had to....

5. ... and I know how I can find things out by myself when I do need to learn something new.

I guess that this might even apply to PhD students.

Ken Dobson Honorary Editor

This was how the chairman, Dennis Chisholm, described the morning's major topic `Higher Still' - the proposed successor to the Scottish Higher Grade and Sixth Year Studies Certificates. It was chosen for this one-day conference on 21 May as the documentation for it had been promised for 1 May. Alas, as the main speaker, Mary Webster, admitted, the materials were still `sitting in a warehouse in Dundee' and the programme has now been postponed for a year! Nevertheless the team, which included Rothwell Glen and Tony Keeley, bravely fielded a series of awkward questions from a critical audience of over 200 physics teachers.

Physics with gusto

If `Higher Still' was a damp squib Rebecca Crawford's team from Glasgow Science and Technology Outreach set the place ablaze. In their first spectacular demonstration Rebecca lay on a bed of sharp nails while someone stood on top of her! This was followed by a deafening explosion produced by cornflour powder igniting in a tin can used to model a grain silo. Hydrogen was then produced by aluminium foil in a solution of caustic soda, and used to inflate a balloon before exploding it with a flaming torch. Using two 2 mW lasers the green spot produced by one was shown to appear much brighter than the red spot from the other, The Australian demonstrator explained that some of their fire engines were now being painted green instead of red as our eyes are more sensitive to green. A small low-inertia electric motor turned when attached to copper and zinc electrodes inserted first in a glass of Coke and then in a fresh grapefruit. Gas-filled sausage balloons were packed into a flask of liquid nitrogen where they collapsed as the gas inside liquefied. When the bunch of deflated balloons was removed and thrown on to the bench the results were dramatic.

As you might expect, the `best wine' was kept to the last. Kenneth Skeldon and two colleagues in the University of Glasgow have built a high voltage generator based on a resonant transformer derived from a standard Tesla coil with a high-Q secondary. This is capable of delivering around a million volts, which produce fantastic lightning flashes. A volunteer from the audience was invited to enter a huge Faraday Cage which was then subjected to these high voltage sparks! For a while the door of the cage jammed but eventually the victim emerged unscathed!

This is, of course, not just an entertainment. The Gusto show is taken into schools and targeted at lower secondary pupils about to make their subject choices. The team also gives large scale physics demonstration lectures and could play to 10 000 children in a month. So physics is fun and physics is relevant to everyday life!

Support for physics teachers

Lesley Glasser chaired the afternoon session, which she opened by introducing the Institute's Education Officer. The Stirling Meeting would not be the same without the `commercial slot' presented again so ably by Catherine Wilson. Physics teachers are an endangered species and the Institute is determined to do whatever it can to support them. Plans are afoot to make sure the Schools Lectures are modified, if necessary, to take account of the educational differences in Scotland. The London-based `Physics in Perspective' course not only introduces sixth-formers to some of the frontiers of physics but gives enough free time for them to visit places of interest in the city - from the Science Museum to Soho. `So they associate physics with enjoyment!'

Another Scottish Update Course is planned for teachers, and a brand new glossy booklet, sent free to all schools, will show pupils that choosing physics is a `Smart Move'. Finally the Institute has just started a major post-16 curriculum project which will include a variety of support materials to keep teachers abreast of continuing developments in physics.

Each year, IoP Teacher of Physics Awards are given to `outstanding teachers of physics who inspire others to continue with and enjoy their physics'. Ann Jarvie, Deputy Head of St Ninian's High School in Kirkintilloch, certainly felt that this was a fitting description of their physics master Pat Cleary, who was presented with his Award at the Stirling Meeting. Of him she said `He encourages and supports his pupils. He doesn't talk down to them and he is concerned about all pupils, not just the high fliers. He has a great sense of humour and enthuses his pupils. Pat's passion for physics is all-consuming; he will beg, borrow and (almost) steal for physics! He only tolerates senior management because they supply him with money for physics!' Before giving his keynote lecture Professor Russell Stannard presented Pat Cleary with his Award.

Venturing beyond physics

In this stimulating presentation Russell Stannard not only summarized current thinking in cosmology, he also considered possible theological implications. The universe is a big place consisting of 10¹¹ galaxies each containing 10¹¹ stars. It may be that 10³⁰ stars have planets and so the universe could be teeming with millions of different forms of life. Is size then the most important thing for us? What goes on in the human head is much more interesting than the nuclear reactions of the sun. Surely human consciousness, associated with the complexity of the brain, is of more importance to us than mere size.

In the beginning

If we ask about the origin of the universe, e.g. `How did it get started?' then we look to science for an answer. On the other hand we might ask a theological question about creation, e.g. `Why is there something rather than nothing?' Current ideas of the Big Bang are based on several independent strands of evidence which Russell discussed in some detail.

Space-time

`It is idle to look for time before creation, as if time can be found before time.... We should say that time began with creation rather than creation began with time.' This amazingly modern concept - that space and time were created together - was asserted by St Augustine 1500 years ago! If time and space are `welded' together time didn't exist before the Big Bang and so we cannot ask what caused the Big Bang. Cause precedes effect.

The future

The universe is expanding but at a reduced rate. Will it eventually stop expanding and start to contract? If so, will it reach a point where it again stops and starts to expand again - the Big Bounce? Or will it collapse completely - the Big Crunch? Alternatively will the universe go on expanding forever? The answers to these questions depend on the density of the universe. The density needed to make the universe start to contract is called the critical density. At present the observed density is around 0.3% of critical density. This would suggest that the universe should continue expanding forever. However, the movements of galaxies and clusters of galaxies indicate that there must be some undetected `dark matter' which, calculations show, increases the density of the universe to within a factor of two of critical density. If this is correct the density at the early stages of the Big Bang would have had to be correct to within 1 part in 10⁶⁰.

DIY universe

A final word of warning to anyone who aspires to building a better universe! If you make your Big Bang less violent the universe will expand and then collapse to a Big Crunch before life has time to develop. Make it more violent and gases will disperse quickly so that stars and planets cannot form. If you make gravity (G) weaker, nuclear reactions won't be triggered and only brown dwarfs will form. Life will be impossible. Make gravity stronger and only fast-burning massive stars will form. These blue giants last for only a million years and there will be no time for life to evolve.

In summary: are we in one of an infinite number of universes because the conditions happen to be just right for us or is this universe a one-off put-up job designed by God? Cosmology neither proves nor disproves the existence of God. However if, on other grounds, you are a believer, current thinking in cosmology shouldn't worry you.

Thanks

To circle the world in 80 days may be interesting. To encompass the universe in less than 80 minutes is, in the chairperson's words, mind-blowing. The day ended with votes of thanks to all contributors and to Jack Woolsey and his team for organizing the meeting.

Jim Jardine

Instead of the customary event in the Easter holidays, this year's Institute of Physics Education Group annual meeting is scheduled for 3-5 July 1998 at Churchill College, Cambridge. The title is `Continuity in the teaching of physics (Keeping the stars in their eyes)'.

The aim is to examine themes which have the potential to form bridges between schools and Further/Higher education: among those already suggested have been astronomy, materials and the history or context of science. Several such themes recur in physics teaching and are therefore dealt with by teachers and lecturers at various levels in schools, further and higher education. The experience of teaching these areas of subject content or particular skills can act as a common meeting place for teachers at all stages to address issues of general concern. It is hoped therefore to highlight the development and interconnection of physics teaching within and between educational sectors. By exchanging good practice and firing the imagination of the pupils, it is possible to influence the future.

Working group sessions will be incorporated into the programme, so that participants have a choice of topic groups to attend and make contributions to a summary document. The session outcomes will then be made available to the other participants. In addition poster sessions will cover linking ideas/themes and successful strategies for inspiring pupils.

Further details can be obtained from The Institute of Physics Conference Department, 76 Portland Place, London W1N 3DH (tel: 0171 470 4800, fax: 0171 470 4900, e-mail: conferences@iop.org).

During the course of 1997, the American Institute of Physics released a number of reports summarizing data gathered on physics degrees, jobs and salaries. These reports came from the Division of Education and Employment Statistics, which tracks and comments on trends of importance to the physics community.

Among these was the Enrolments and Degrees Report (April 1997), which indicated that the US physics community was in a period of adjustment. Enrolments in degree programmes for both graduate and undergraduate majors were experiencing substantial declines, and a decade-long increase in physics doctorates appeared to be levelling off. At the same time first-year graduate entry had continued to decline, dropping 26% from 1992. Introductory physics course enrolments had remained strong at around 380 000 students in 1996, but the number of bachelor's degrees conferred had dropped to 4263 in 1995 - the lowest figure in 30 years - and by 1996 this figure had dropped again to 4173. The 1996 Bachelor's Degree Recipients Report (June 1997), which contained data on junior-level enrolments, indicated that this low level of undergraduates might well continue for at least two more years.

Median starting salary for the 1996 physics bachelors with potentially permanent full-time positions was $31 000, and almost two-thirds of those entering the job market intended to pursue advanced study at some time in the future. Although 33% of those pursuing graduate degrees were doing so in physics, a growing fraction were choosing to study in cross-disciplinary areas such as medical and health physics.

From the 1996 Initial Employment follow-up of 1995 physics degree recipients (July 1997) it appeared that 12% of the 1461 new PhDs were women, and non-US citizens represented 48% of the total. New degree recipients remaining unemployed during the winter after receiving their degrees declined compared to the previous year, and new PhDs were more likely to accept potentially permanent positions than in the previous year. Of those accepting potentially permanent jobs in the USA, 46% were working outside the field of physics, however.

These reports may be obtained from Audrey T Leath of the Public Information Division at the American Institute of Physics (email: fyi@aip.org).

American undergraduate students interested in research should be thinking soon about applying for the `Research Experiences for Undergraduates (REU) programme', which is supported by the National Science Foundation. Several hundred `Sites' in a variety of departments and laboratories in all fields of science, mathematics and engineering allow students to participate in the research of that institution (within groups of about ten or more), and application deadlines are usually in February or March of each year. Enquiries should be directed to each individual site for application procedures and for information on the research topics available there. The list for Physics, Materials and Astronomy can be viewed at: http://www.nsf.gov/home/crssprgm/reu/reupma.htm although the full list is also recommended since some sites in related fields often have components of interest to physicists and astronomers.

1998

27 January Oakham School, Rutland Metals in action (Dr I Hutchings)

3 March Oakham School, Rutland Physics of the Channel Tunnel (Mr A Fairbairn)

4 - 6 April Malvern College Physics update

28 April Oakham School, Rutland Surfaces, seeing single atoms (Dr D Sykes)

4 June Rugby School Annual day meeting for Physics teachers

3 - 5 July Churchill College, Cambridge Education Group annual conference

4 - 6 July University of Manchester Physics update

Further information on Group activities may be obtained from Mr Philip Britton, Leeds Grammar School, Harrogate Road, Leeds LS17 8GS.

A recent report from the UK's Royal Society has produced a figure for the cost of essential laboratory equipment required to teach science effectively. Excluding technician support, books and stationery, photocopying and audiovisual equipment, the sum is estimated at £11.38 per pupil per year.

The report, Science Teaching Resources: 11-16 year olds, is based on the needs of an 11-16 school with 150 pupils in each year group, and it updates and expands the Society's 1990 report which indicated a cost of £8.86 per pupil per year. Sponsorship by Esso has enabled a copy of the report to be sent to every secondary school, and the Association for Science Education is producing a complementary publication to cover science in primary schools.

A comprehensive list of the minimum equipment required to teach practical science effectively was arrived at after extensive consultation with science teachers and advisers over a two-year period. Each item was costed and given an expected lifetime, enabling an accurate estimate of annual costs to be calculated. This should make the report an invaluable planning document for reviewing provision within a school science department, for preparing spending and development plans and for equipping new laboratories or refurbishing existing ones. In addition to the printed form, spreadsheet files of the costed equipment list can be downloaded from the Royal Society's web site (http://www.royalsoc.ac.uk/st_pol21.htm) or obtained on disk from John Lawrence at the ASE (fax: 01707 266532, e-mail: johnlawrence@ase.org.uk).

There have of course been many changes in science education since 1990 which have affected resource provision. Among these have been an increase in the amount of pupil investigation, with pupils following up their own ideas; the continuing development of information technology equipment and its greater use in schools; and increased emphasis on matching learning activities to pupils' abilities, resulting in alternative teaching strategies being devised by teachers. No comprehensive surveys into funding levels for school science departments have been conducted in recent years, but data collected during school inspections for the Office for Standards in Education (OFSTED) indicate that expenditure was around £8 per pupil per year for 1995/6. To address this current lack of hard evidence, a short questionnaire is enclosed with the report for schools to complete. The results of this survey will then be analysed and disseminated.

Banska Bystrica in Slovakia will be the venue for a major international conference entitled `Science Teacher Training 2000' taking place on 21-26 June 1998. The meeting is being organized by the TEMPU (Phare) Structural Joint European Project and financed by the European Training Foundation of the Commission of the European Communities.

The aim of the conference will be to bring together teacher-trainers and teachers from a wide range of educational institutions within the international community to share experiences and identify perspectives on the collaborative training of future biology, chemistry and physics teachers. The programme will focus on: teacher-training curricula for the 11-18 year-old age range; profiling competencies for the new science teacher; new approaches to teaching and learning; approaches to the teaching of integrated science; and information technology in science teacher-training. Further details are available from Jan Klima, Physics Department, Faculty of Natural Sciences, Matej Bel University, Tajovskeho 40, 97400 Banska Bystrica, Slovakia (fax: +421 8833132, e-mail: stt2000@fhpv.umb.sk).

Practical tips and realistic strategies for women working in the fields of science, engineering and technology are supplied in a new handbook, Cracking It!, published recently. Based on the experiences of those who have succeeded, the book is a mine of invaluable information and advice, with profiles of women who have progressed and overcome obstacles in a diverse range of SET sectors, yet still remained enthusiastic about their jobs. Sponsors for the book included the UK Department of Trade and Industry, Women into Science and Engineering (WISE) and the Wellcome Trust.

Cracking It! (ISBN 1 840190000) by Josephine Warrior costs £10.99 and can be ordered from Training Publications Ltd, PO Box 75, Stockport SK4 1PH (tel: 0161 480 5285, fax: 0161 474 7502).

Meanwhile, schoolgirls across the UK should be getting the chance to sample technology in their own special environment, thanks to a mobile technology classroom which is part of the Engineering Council's WISE campaign. This converted 40-foot (12 m) vehicle will permit girls to enjoy using equipment such as CCTV, signalling, pneumatics and computer-aided design away from boys, who traditionally tend to dominate and monopolize technology lessons. The vehicle will be touring schools around the country, and has been sponsored for three years by four major transport and communications companies.

1998

7 - 10 April, Tours, France Towards the global university: strategies for the third millennium Info: Lisa Smith, University of Central Lancashire (tel: 01772 892255, fax: 01772 892938, e-mail: l.smith@uclan.ac.uk)

5 - 10 July, Darwin, Australia CONASTA 47 - annual conference of the Australian Science Teachers' Association Info: CONASTA 47, Conference Secretariat, PO Box 778, Nightcliff NT, Australia 0814 (e-mail: conasta47@topend.com.au)

A special event at the Royal Institution in London was held in October as part of The Institute of Physics programme of activities in Electron Centenary year, and also to mark the award ceremony for the Institute's schools poster competition.

Professor Colin Humphreys, the Institute's new Fellow in the Public Understanding of Physics, gave a special schools lecture entitled `The amazing electron - how it will continue to change our lives', intended for all ages from Year 7 to Year 13. He looked to the future uses of the electron, including a new type of light bulb based on a light-emitting diode that lasts for 100 000 hours and consumes only one tenth of the energy of normal bulbs. He also covered blue lasers, which can write ten times more music on a compact disk than at present, and the dream of room-temperature superconductors in which the electrical resistance of materials dramatically drops to zero.

After the lecture, Past President of the Institute Sir Arnold Wolfendale presented the prizes for `The electron in our lives' poster competition. The judges had been seeking imaginative and innovative ideas for posters which not only showed artistic ability but also conveyed the everyday relevance and impact of the electron. A selection of the winning entries are to be reproduced as a set of posters and will be widely distributed to schools and colleges in the UK and Ireland to celebrate the centenary year.

All the six First Prize winners received computers with Internet links for their schools, they toured both the Royal Institution and the Institute of Physics, and on 25 October they all flew to Washington, USA, for a week of events arranged by the Institute in collaboration with the American Physical Society. They were:

Year 7 Rebecca Menashy, North London Collegiate School, Edgware

Year 8 Beverley Hall, Hitchin Girls' School, Herts

Year 9 Elaine Oliver, Cramlington Community High School, Northumberland

Year 10 David Sarginson, Cramlington Community High School

Year 11 Alistair Gemmell, Cramlington Community High School

Year 12 Sarah Dunn, Cramlington Community High School.

Figure 1. Jummy Ayodeji with Chris Llewellyn-Smith, Director General of CERN.

Jummy Ayodeji (see figure 1) of Townley Grammar School for Girls, Bexleyheath (who was runner-up in Year 12) won a trip to CERN donated by the Particle Physics and Astronomy Research Council. The remaining runners-up and special merit prizewinners - Zoe More O'Ferrall, Robyn Ball, Samantha Palmer, Rebecca Morris, Michelle MacDonald, Caroline Mudd and Luke Humphries - all enjoyed a family day out at the Science Museum in London. One example of a winning poster is shown in figure 2.

Figure 2. The poster that won the First Prize for Year 7.

PAWS, the Public Awareness of Science and Engineering, has a Drama Fund which encourages new drama for television centred on science and technology. Every year around 150 writers propose ideas to the PAWS fund, and many benefit from the contacts and information service provided by the PAWS office. Grants of £2000 are available for the development of ideas into drama treatments, and prizes of £5000 and £2000 can be awarded for the treatments judged to have the best potential for success.

In addition, `Ideas-sparking evenings' form a large part of the PAWS calendar: attracting many writers, scientists and engineers, these evenings enable writers and drama producers to find out about a wide range of science and engineering topics, with talks given by top researchers and managers from major organizations. Informal receptions after the talks provide writers with an opportunity to follow up their ideas in discussions, as well as supplying a variety of role models for their characters.

The PAWS Office is at OMNI Communications Ltd, Osborne House, 111 Bartholomew Road, London NW5 2BJ (tel: 0171 267 2555, fax: 0171 482 2394).

Apparatus developed for teachers as a low-cost means of demonstrating optoelectronics has now proved capable of reproducing some of the most demanding experiments in optics, according to an article in a recent edition of Opto and Laser Europe. Franco Quercioli and colleagues at the National Institute of Optics in Florence found that the popular polymer building blocks could do the job of more expensive commercial metal components, and not only saved teachers money but in many cases had distinct advantages. The low cost, reduced weight and compact size of the Lego blocks are all desirable characteristics in a laboratory set up for educational or research purposes.

Among the components produced were lens holders, adjustable mirrors, filter tilters, minitables for rotation or sideways movement, and supports for lasers, posts and rails. Only a very few parts had to be separately machined or cut from standard baseplates. The resulting instruments included microscopes, beam expanders and interferometers (the latter being among the most accurate of all optical instruments). It is claimed that with some more research Lego may soon appear on many optical benches outside the classroom. It is also believed that the Lego company in Denmark is intrigued by this work and may consider involvement in the future.

All the Letters to the Editor in this issue are in the same PostScript or PDF file.

Contents

Physics and history Arthur I Miller Department of Science & Technology Studies, University College London, Gower Street, London WC1E 6BT, UK

Physics and history: a reply David Miller Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK

Cathode rays, the electron and Thomson's discovery John Harris 33 Glentham Road, London SW13 9JD, UK

Vectors: swallow them whole! David Wheeler Mahanakorn University of Technology, Bangkok, Thailand

A use of spreadsheets to model special relativistic phenomena is presented, based on the connection between electric and magnetic fields in special relativity, suitable for use with A-level students. The time dilation equation is used to carry out transformations between reference frames that show the connection between the fields quantitatively and allow further investigations to be carried out.

Feynman diagrams can be used to explain deep inelastic scattering, but it must be remembered that the emission and absorption of a photon are not independent events - the underlying field is important.

An experiment with undergraduates in a physics laboratory has shown that thorough preparation before a lab session improves students' performance in the lab and that follow-up work can lead to meaningful learning.

A student project to design and build a musical staircase is described. The completed musical staircase covered eight steps, allowing a simple musical scale to be sounded.

The equivalent resistance between any two terminals of a regular hexahedron is calculated on the basis of symmetry analysis instead of analysing the circuit with current flow in every wire.

Teachers of physics need to be constantly on their guard against misleading ideas and inappropriate ways of delivering the subject. It is suggested that including the laws of Charles and Ohm, when introducing the physics of gases and of electrical conductors, actually makes these topics more difficult to present.

This article describes the progress made towards real engineering applications of high temperature superconductors (HTS) in the ten years following the Nobel Prize winning discovery by Bednorz and Müller in August 1986. Examples include HTS wires and tapes for more efficient and powerful electric motors and for increasing the electrical power into the heart of modern cities, HTS permanent magnets for levitation, microwave filters for cellular telephone networks, SQUIDs (superconducting quantum interference devices) to monitor foetal heart and brain signals, and a new generation of superfast logic devices based on the flux quantum.

We show how it is possible to construct a high temperature superconductor levitation motor in an introductory physics laboratory. It is suitable for classroom demonstration and uses a simple yet efficient cooling method.

This article explains how the graphics calculator can be used in simulations of physics experiments and also how its use for plotting graphs requires a shift in emphasis from obtaining an experimental result to evaluating it.

Assuming that during the rated lifetime of a bulb roughly half of the radius of the filament evaporates, we can estimate the mean rate of evaporation. The filament's operating temperature can then be deduced from the Catalogue using linear interpolation. The probable reasons for the bulb's failure are also mentioned.

The aims and principles underlying recent reforms in the junior school physics course in China are explained here. The focus is on developing students' abilities and the benefits of experiments rather than the simple transfer of knowledge from teacher to students.

Peter Higgs, FRSE, FRS held until recently a personal chair in theoretical physics at the University of Edinburgh and is now an emeritus professor. Peter is well known for predicting the existence of a new particle, the Higgs boson - as yet unconfirmed. He has been awarded a number of prizes in recognition of his work, most recently the Paul Dirac Medal and Prize for outstanding contributions to theoretical physics from the Institute of Physics and the 1997 High Energy and Particle Physics Prize by the European Physical Society.

This book has the ring of perceptive experience and focused research, as the author brings together a wealth of information about the misconceptions and reasoning difficulties that students have in learning physics. Though he is concerned primarily with students starting physics in `high school through first year college level, including basic aspects of the course aimed at physics and engineering majors', this book will have much to give to anyone concerned with teaching any students the fundamental concepts of physics.

Part 1 of the book, and the part which will be of most use to physics teachers in any context, considers the difficulties that students have in learning each of the main areas of physics, and in critical thinking. Noting that research shows a poor level of understanding of physics in many students, `because the students had not had the chance to master the necessary prior concepts and lines of abstract logical reasoning' he seeks to `bring out the conceptual and reasoning difficulties many students encounter and to point up aspects of logical structure and development'. And this he does to very good effect. He is keen to stress, however, that clear, logical and lucid explanations are not sufficient in themselves but necessitate the students being actively engaged in the learning process. He acknowledges that `research is showing that didactic exposition of abstract ideas and lines of reasoning to passive listeners yields pathetically thin results in learning and understanding'. Oh, that all involved in teaching physics, in Higher Education or in schools, would recognize this. One of the main reasons that so many students are put off physics is because their teachers present the physics to them, as passive receivers, and do not expect them to actively engage with the ideas and concepts.

Part 2 of the book provides a selection of excellent and penetrating questions in physics which force the student to engage with concepts of physics. These would be particularly useful for teachers of physics to students beyond 16, who can cope with tough thinking and are not put off by mathematics including algebraic equations - in the UK context these would fit into A-level courses. The final section provides a teaching sequence for the introduction of energy and the classical conservation laws that most physicists will find eminently satisfying.

Altogether this is a tour de force from a highly experienced physics teacher who has a strong love for, and commitment to, his subject and the desire to share the intellectual joys therein with his students. It is rigorous, stimulating and enjoyable. I commend it to all other teachers who still believe in and enjoy the elegant simplicities of good physics.

If I have one complaint about the book it is a personal one: that physics is presented purely as a cognitive activity necessitating only intellectual activities. Some, but not all, of us would want to assert that teaching and learning physics involve the emotions, motivation and commitment, as well as the intellect. This book is about teaching classical physics in the best classical tradition. Perhaps another book will deal with the more holistic, personal aspects of learning physics which students and society at large are increasingly demanding.

Steve Adams' Relativity is a comprehensive and highly readable introduction to a subject of broad interest and enduring popularity. It is pitched at just the right level for serious sixth-formers or for undergraduates striving to understand the physics that underpins more mathematical treatments of relativity, and will also be of interest to their teachers. The book richly deserves a place in school and college libraries, but the present edition is marred by so many minor misprints that I would be reluctant to make it required reading for novice students, despite its many attractive features.

Relativity has an admirably straightforward structure: an introductory chapter outlining classical physics is followed by two substantial chapters on special relativity and a single chapter on general relativity and cosmology. The first of the two special relativity chapters is pivotal since it establishes the `physics-led' rather than `mathematics-led' approach of the book. It achieves this by basing many of its arguments on the behaviour of `light clocks' that measure time by counting the successive reflections of a light pulse as it bounces back and forth between two parallel mirrors separated by a fixed distance. Judicious use of these idealized clocks enables the author to expose all the well known phenomena of special relativity without having to call on the Lorentz transformations at all. The Lorentz transformations are included, but they don't make their first appearance until page 111, and even then their main function is to prepare the way for Chapter 3, which takes the reader deeper into the structure of (Minkowski) space-time and revisits, in a more mathematical way, many of the topics introduced physically in Chapter 2. This double approach to issues such as time dilation and length contraction has been well thought-out and well executed, and seems certain to aid effective learning on the part of students, even those who are reading the book on their own, without the guidance of a teacher or lecturer.

The survey of general relativity and cosmology that occupies the book's fourth chapter is much less detailed than that of special relativity, but equally engaging. The treatment of Einstein's geometric theory of gravity is again primarily physical, though the use of elementary calculus is more evident than in the earlier chapters. Only a small proportion of the chapter is devoted to cosmology as such, but the basics are well explained and the chapter is neatly rounded off by 20 pages on black holes and gravitational waves.

Students can sometimes lose their way in lengthy chapters, so a book of 280 pages with only three major chapters may seem a somewhat daunting prospect to some. However, each of those chapters starts with a very helpful block diagram showing the relationship between key ideas, and there are plenty of subheadings to help guide and orient the reader. These signposting devices, together with the summaries and problem sets that end each chapter, make Relativity a useful and effective guide to the endlessly fascinating world of space-time.

Unfortunately, as indicated earlier, this potentially very valuable text is marred by a number of small but irritating errors. The most prevalent of these concerns the gamma factor that appears in the Lorentz transformations and in many of the results that follow from them. In several different places (pages 118/9, 121, 159) gamma makes an unannounced transformation to g, presumably as a result of some kind of font problem in the production process. Similar problems beset Figure 3.25 and one or two of the other figures. Another kind of gremlin seems to have been at work in some of the summaries; what should have been neatly stacked equations and uniformly indented paragraphs have somehow become misaligned or disarrayed.

Other problems, more clearly of the author's own making, result from the decision to use the symbol p₄ to indicate an energy-momentum four-vector, and from the rather old fashioned practice of using ict, rather than ct, as the zeroth component of the position four-vector. All of these problems are quite minor, but they are of just the sort that might confuse algebraically timorous students who half expect that relativity will be incomprehensible.

Despite its production problems, Relativity is a well planned and well written book which I am pleased to own. I will recommend it to those who will not be confused by its misprints, and I hope that a corrected edition will eventually be published so that the book can achieve the full readership it deserves.

Davis and Falconer's book will help dispel the impression that Thomson discovered the electron, collected his Nobel Prize and disappeared from the history books. This interesting book locates Thomson's ideas in their historical and philosophical context, revealing a consistent world view that runs through all of his work. In fact this world view could be regarded as the key to why we remember Thomson as the discoverer of the electron rather than any of the many others who were carrying out similar experiments at the same time. It is well known that the name `electron' had been coined by Stoney six years before Thomson's 1897 discovery, but for Stoney an electron was the basic unit of charge and not a subatomic particle. Thomson's interest in gaseous discharge was linked to his desire to explain the underlying structure of matter and link it to Maxwell's electromagnetism. For Thomson cathode rays revealed more than a basic unit of charge, they revealed a new, subatomic particle that happened to carry this charge. This is why Thomson declined to call his `corpuscles' electrons for many years - the discovery was more a step along the way toward a theory of atomic structure than an end in itself. It could be regarded as the start of particle physics. It demonstrated that there was a particle common to all atoms and that a unifying theory was possible.

Thomson continued to develop his atomic models and managed to account for ionization, radiation, chemical combination and radioactivity in a consistent way before his model was superseded by the Rutherford planetary model. But even Thomson's attempts to unify atomic physics by constructing all atoms from similar corpuscles were themselves a consequence of his underlying belief that the ultimate ground of physical reality was the ether. This idea, which ties him to the late nineteenth century, had developed from his early work in electromagnetism and analytical dynamics in which corpuscles emerged as structures in the ether (originally he thought they were some kind of vortex ring) interacting via Faraday tubes (localized connections in the ether). The usual cursory mention of the `plum-pudding model' in which Thomson's negatively charged corpuscles are embedded in a vague positively charged fluid does little justice to the subtlety and adaptability of Thomson's atomic theories. In later life he accepted the predictive and explanatory powers of relativity and quantum theory but saw them as mathematical constructs and not directly representational. He still identified space with the ether and thought that deeper levels of explanation were required.

The structure of the book is interesting. There is a short but significant foreword by David Thomson, JJ's grandson. This affectionate reminiscence is an important point of contact, since most of the book deals with his ideas and influence. The rest of the book treats his life more or less in chronological order but the chapters are separated by a number of papers written or presented by JJT (mainly drawn from Proceedings of the Royal Institution or Philosophical Magazine). These account for almost half the book and are fascinating to read in parallel with the text. They have been reproduced as facsimiles, and this makes them slightly more difficult to read since the quality of the originals was not wonderful, but it does give them an authentic flavour (although I would have occasionally liked a little more information about some of the line drawings).

The other important aspect of the book is its emphasis on Thomson's influence at the Cavendish, where he succeeded Rayleigh as Professor of Experimental Physics in 1884. He is described as `a committed college man, with a reputation for attacking fundamental problems, seeking unification within an ether-based, mechanical physics; a man with an enormous fertility of theoretical invention and a fairly cavalier approach to experiment'. He encouraged and supported a growing number of students, many of whom went on to carry out first rate work, and the Cavendish entered the twentieth century as the most important centre for fundamental atomic research in the world. Thomson's contributions to fundamental science were rewarded with the Nobel Prize; he also had a pivotal advisory role to government, was President of the Royal Society and Master of Trinity College. For many years he was the most important scientist in Britain, and yet few physicists know that much about him. This book gives us an opportunity to put that right, and I would recommend it to anyone who wants to understand the transition from classical to modern physics and learn about a modest but imposing man of unusual vision and compassion.

This is a unique book which attempts to present the many and varied scientific models used to study matter along with an extensive collection of specific types of matter upon which these models can be brought to bear. The language and tone of the writing are both interesting and thoroughly scientific, and yet the author completely eschews the use of equations throughout the book. The topics include many from both physics and chemistry, and the book provides a good introduction to the way in which these two disciplines overlap to form the field of materials science.

The order in which the topics are presented is interesting, with roughly the first half of the book putting forth several models invoked in the study of matter: forces or interactions; energy; thermodynamics and entropy; fractals and chaos; atoms, molecules and chemical bonding. The second half of the book then presents the applications of these models to ever more complex types of matter, beginning with electrons and fundamental particles, proceeding through atoms and molecules, and building up eventually to polymers, mixtures, solutions, surfaces and a host of others. The sheer number of examples presented is astounding, and they vary from the more esoteric (like the nucleation of freezing in water droplets by pseudomonad bacteria) to the commonplace (like silly putty). Many of the topics are of current interest, including electrorheological fluids, glass `xerogels', and liquid crystal films as information storage devices. The presentation is consistently interesting (with the help of figures and of cartoon illustrations by Andrew Slocombe), and is further enhanced by the copious chapter endnotes and bibliography. With so many examples about which a reader might like to learn more, these almost always provide an entry point into the relevant literature on the topic.

The only thing unclear about this book is its intended audience. The complete avoidance of equations and the numerous everyday examples would tend to indicate that it is aimed at a very general audience. However, the breadth and depth of the topics covered, along with the unabashedly scientific tone of the language, seem better suited for a reader with a background in chemistry or physics. While perhaps not appropriate reading for an introductory-level course for undergraduates, it might be a good choice in an advanced seminar for either physics or chemistry majors with an interest in exploring areas of materials science.

Perhaps the greatest strength of the book is its frequent demonstration of the power of using multiple models to examine the same phenomenon. The author is at his best when he reminds us that, `Each model we use provides us information on one aspect of a problem, but we can combine them so that with experience they form an integrated intellectual process'. Finally, as the title may suggest, a central theme throughout the book is the notion that science as a human endeavour is an ongoing, evolving process. The models we have today may not be the models of tomorrow. To quote from the book again, `... the number of possible states of matter is limited only by your ability to perceive them'. Because this book gives us a glimpse into the rapidly changing world of materials science and allows us to see both the variation between and the complementarity of the different models which have evolved, it is a worthy contribution to the literature.

Who is Uncle Albert? The figure at the centre of Russell Stannard's More Letters to Uncle Albert, as well as his earlier adventures in modern physics, is suitably enigmatic. Clearly the genial, white-headed old scientist on the book's cover owes much to the appearance and anecdotal personality of his more famous namesake. This collection of big questions from real children, however, sees some slipping of the authorial mask and it is often uncertain exactly how fictional our hero really is. This would not matter, except that the fact that the benevolent oracle is a physicist rather than a saint or a poet or Father Christmas says a good deal about the position of science at the centre of our modern culture.

Most telling is the way in which Albert is called upon to answer questions that might normally be considered to lie far beyond his professional remit. So, after tackling the mysteries of space and time with familiar aplomb, and pausing only to encourage his young readers with the assurance that `the answers to the next questions will be easier', he brings us face to face with cosmic teasers like `Was there really an Adam or Eve?', `Why are we killing each other and not living happy and peacefully?' and `Is God left handed or right?'

Albert is at his most revealing here. Fully aware that he is caught on the farthest parameters of his discipline, he retreats into a traditionally passive description of the scientist's role: `Scientists have the job of understanding and describing the world we live in. But that doesn't mean we can explain why the world is like it is'. One suspects that the subtlety of this distinction will be lost on most children, much as it was on the medieval church; its policy of non-engagement certainly leads to some of the least satisfactory responses in this book. Under its influence Albert resorts to a kind of biological determinism when trying to account for the existence of war. Unfortunately, shrugging references to our DNA codes, like other forms of determinism, cannot withstand the assault of a child's repeated `but why's', assiduously reductive as the best efforts of any particle physicist.

Besides spells of detachment, and occasional wobbles brought on by his fictional/non-fictional identity crisis, Uncle Albert's tone is sometimes betrayed by uncertainty about his book's target audience. An answer will whistle over the head of a five year-old enquirer, perhaps reaching the ten and eleven year-olds who comprise the attentive audiences at his many school visits, or more likely end up in the laps of the well-meaning parents who will slip this volume discreetly into a Christmas stocking beside a copy of the latest Spice Girls CD.

So much for negatives. Most of what has been said so far is by nature of a qualification to the courage, integrity and skill with which Uncle Albert negotiates the kinds of questions that the majority of adults are either too frightened or numb to face. At their best the replies show that scientific enquiry entails a disciplining rather than a repression of feeling; they are happy to convey vastness with the thrillingly cumulative `big, big, big' rather than a grown-up big to the power of three. The children, of course, know this already, and the other great pleasure of this peculiar book is their freshness of perception and the way it can startle us once again with the blueness of the sea or the whiteness of snow.

I opened this book with considerable enthusiasm since it looked to be just the kind of thing that could be very useful for first-year undergraduate teaching. It is published by the Cambridge University Press, one of the authors comes from the University of Leicester and the other from the Israel Institute of Technology and the first surprise that I had was that the spelling is American. The second surprise was that the authors make a point in the preface that no calculus is used in any of the calculations. I then twigged that this book is designed specifically for the American market; that, of course, does not invalidate it but I find it difficult to see exactly where it can fit in this side of the Atlantic. The next thing that I looked at was the list of physical constants to see how good the proofreading was. There is one error in the (quite short) list, which made me wary. However, I subsequently found very few typographical errors, so there is not much to complain of there.

The general level of questions is certainly way beyond school physics and is quite appropriate to first-year university work but the positive non-use of calculus would make me think twice about recommending it to a student for his or her private study. Having said that, I would be very happy to use many, if not most, of the questions as tutorial examples. Any student, or physics graduate for that matter, who could answer all the questions in this book would have a very sound grasp of basic physics. A particularly good feature is the provision of comprehensive solutions to all the problems, and these are grouped together in the second half of the book. They are a great comfort when one feels a little unsure of how best to tackle a particular problem.

The general presentation and style is good. There are three main sections, each of which is prefaced by a brief digest of the relevant physics. I like that, since most textbooks these days are far too large and wordy and make it hard for the student (a) to carry them around and (b) to get an overview of a topic. There are of course dangers in such a brief digest and I certainly found a number of items to which I took exception. Some of these are simplifications which might be appropriate and acceptable at a relatively low level but are certainly not acceptable at university level. Others are simply incorrect at any level. An example of the first can be found in the first chapter, which is about Mechanics. A table of moments of inertia refers to unspecified symmetry axes. Most of the bodies in this table have several symmetry axes, so which one does the student choose? There are lots of good questions following the summary but too many of them, for my taste, have a military connotation and I suspect that many teachers might also find them a little disquieting. No people, only `targets', actually appear to get shot or bombed but such questions still make me feel slightly uncomfortable.

The next chapter is entitled Electricity and Magnetism. The digest contains all you need to know but I do not like, for example, `The electric field and electric charge vanish everywhere inside a perfect conductor'. The first of these is only true in the static case and is a case of misleading oversimplification. I am not sure what the second means at any level other than the most trivial! There is a missing sin(θ) at the bottom of page 50 which could mislead but is presumably a typographical error. The expression of Faraday's law is oversimplified in that it is correct only for a single-turn circuit. It is also stated backwards, which is curious. Again there are lots of good questions, which range from the easy and confidence-building to the quite demanding.

Chapter 3 is is entitled Matter and Waves and seems to be everything else, including relativity which might have gone in the Mechanics chapter to be logical. In the digest section I read, and can accept, that water is effectively incompressible but I am still trying to work out why air is also incompressible `if we do not consider sonic or supersonic motions'. The definition of the mole is most curious, a fair approximation but not correct. What is wrong with the standard `number of entities (atoms) in 12 g of carbon-12'?

The section on the Doppler effect is far too simplified both for electromagnetic waves and for sound waves. The first ignores relativity and the second ignores the speed of the medium. The section on the Compton effect refers to light scattered by a free electron. Now I know that this is technically correct but it is more usual to refer to the more common and practical case of high energy electromagnetic waves such as x-rays. In beta decay, we are informed, a neutron disintegrates into a proton, an electron and an antineutrino. The neutron certainly does this but it is far too simplistic a description of beta decay in a nucleus even if we ignore the emission of positrons in beta+ decay. Another batch of questions follows, finishing with ten on relativity. Most of the questions are unexceptional although the answer to question 449, which asks why a 15 m focal length refracting telescope is more difficult to build than a reflecting telescope with the same magnification, baffles me entirely. The image is always formed at the focal point of the objective whether it is a mirror or a lens! There might be a subtlety to do with catadioptric instruments but that is not apparent in the question or the answer. I must confess also that I have a prejudice against absurd questions on relativity such as those which have to do with observers measuring lengths of rods as they fly past at nearly the speed of light or alien spaceships travelling at 0.6c firing missiles all over the place. I do wish that designers of questions on this topic would stick to real-life relativity as it is at present. I suppose that, one day, an alien flying past the Earth at 0.998c might fall in love with an Earthling - but I doubt it!

Overall, do I commend this book? With reservations, yes. It is a good idea which, unfortunately, misses the British market by falling between two possible constituencies. This is not to say that it is of no use to teachers. Both sixth-form teachers and HE teachers can draw many good ideas from the questions for teaching but, as I said at the outset, I would hesitate to recommend it as a student book except in a first-year university course at a traditional post-school level in which calculus is not used, and I do not think that there are many of those around.

For a teacher who has spent many years teaching practical electronics in a laboratory using real live components, it is difficult to contemplate doing it all on a circuit simulation program. Indeed, much of the challenge and satisfaction gained from learning, teaching and doing electronics comes from the construction work, the practical hands-on problem-solving and the `getting it to work' excitement. With this background I approached this simulation program with some scepticism. I was further frustrated by being provided with only the paper handbook version and not the software itself to try out. The chance to try the simulations and blow up components on the screen might have been fun!

The software is available for Windows 3.1 and Windows 95 and also for Macintosh computers. The Crocodile Clips program is driven by lots of icons or buttons. Button bars provide a wide range of symbols for every conceivable circuit component, and clicking on these adds them to your screen display. The symbols can be moved around the screen and joined together using the mouse. A crocodile icon allows you to delete parts of your circuit by swallowing it up.

The circuits become `active' when you click on a switch and complete a circuit with a power supply. Ammeters and voltmeters can be included and will give calculated simulated readings. Components that are subjected to excessive stress will explode, we are told, on the screen and then you are given an option to make amends and replace the damaged item. Perhaps this is cheaper than the real thing, but is it too easy just to try it without any real thought when there is no risk to real components?

The support book provides a number of problems and circuits to try out as well as several supporting chapters which deal with fundamental concepts of electricity such as potential dividers. The book aims to give the reader an understanding of electronic circuits and certainly goes well beyond just providing instructions for use of the software. Much of the content of the support chapters would be found very useful by many students following more traditional approaches to electronics. In many ways I think that this book, with its accompanying software, could provide an excellent study guide which could be followed with little or no teacher support. The problems would arise when the student attempts to make the transfer to working with real components. Towards the end of the book a little space is given to ideas about `Converting to a real circuit'. This section seems to me to be quite inadequate without a lot of teacher input and support for the real practical problems that always arise - even when the student has a good understanding of the basic theory. Designing a strip board solution or a printed circuit board layout needs much more guidance than this sort of book can give.

Discovering Electronics with Crocodile Clips looks like a well thought out and presented additional resource for the teaching and learning of electronics. I think, however, that only an actual trial of the software can give a valid assessment of its true value and potential.

NB. This book was reviewed without access to the software that it relates to.

The number of CD-ROMs for science revision at GCSE seems to be growing at some pace, and this latest addition offers a `complete revision guide' to the physics component of dual award science. The disc uses the idea of the `Ultimate Staffroom' to take student through the main topics of physics. The staffroom contains Joule, Faraday, Newton, Rutherford and Einstein of course, but we also have Benjamin Franklin, Zhang Heng (the Chinese inventor of the seismometer) and Caroline Herschel, the only female member of the physics department. Each one takes us through an area of physics. Joule talks us through Energy, with a Coronation Street accent; Zhang Heng takes us into Waves, using a take-away Chinese voice; while Herschel (for `The Earth and Beyond') thankfully uses BBC English, despite the fact, as we are told, that she was born in Germany.

I have got to admit that I like the way these sections are presented, although my cool 15 year-old daughter was less amused. Each topic `lesson' is well structured and the speaker takes us through it simultaneously with the written text on the screen. The sound and text combine well. In addition to tutorial-style sections on every one of the main topics (with Newton of course for `Forces and Motion') the disc has a Quiz section with a range of multiple choice questions fired at random from the Steamship Europress. If you get them right Einstein says `you're a clever clogs' but a wrong answer receives a `Nein, Nein, Nein'. The disc also contains `Investigation' type activities, and a section which the blurb describes as `real experiments in the virtual laboratory'. This may be strange expression but their `Virtual Circuit Board' is perhaps no more disconnected from the real world than the Worcester Circuit Board that we all know and love.

The disc also has a substantial section of `Exam Practice', which allows the student to try a range of past questions and check answers against the supposedly correct ones. Utilities such as a word processor for making notes, a calculator to help with numerical questions and a `Formula sheet' giving a summary of all the formulae needed at this level are available at any time while the disc is in use. My feeling is, sad though I may be, that this is an enjoyable and amusing disc to use. It will be of great benefit to students revising at home and at this price (£19.99) is an excellent buy. Unlike many CD-ROM and Internet resources I have seen, the material on the disc has at least been proofread and checked for accuracy.

Nothing on the packaging suggests what age group this is for, which is remiss for a product one cannot easily browse through before purchase. The audio-visual presentation and the liberal sprinkling of juvenile humour suggest a top primary or lower secondary audience, but many of the concepts covered would prove very difficult. The text-based parts are definitely suited to much older students.

The instructions for loading are clear but subsequent operation with the mouse is not explained. Fortunately there are no unusual features. The long opening sequence becomes tedious but a few mouse clicks cut it short. The introduction, a lengthy sequence explaining that the history of the universe is the greatest detective story ever written, also merits little attention.

The place to start the content proper is one of the two time lines, covering the evolution of the universe from the Big Bang and recounting developments in astronomy from 4000 BC to the present. Clicking on marked points reveals additional text, but it ranges from trivial to far too difficult. The main interactive presentations are in two groups. `Ideas' covers a dozen well-established topics from `Heroes of the Revolution' (Copernicus, Kepler and Galileo) to the `Theory of Everything'. `Brain Elastic' explores about 15 open-ended questions such as `Why haven't we met aliens?' and `Is time travel possible?' Each topic has an introduction followed by a choice of additional sequences (for example, more about the three `heroes'). The treatment is often flippant, but with a core of sensible science.

On most screens an icon hides the `PDA' or `Personal Digital Assistant', explaining with text and photographs more about the concepts in the `Ideas' and `Brain Elastic' sections, plus a glossary of about 300 terms. Most of the factual information is in this section, a lot of it requiring a high level of comprehension. The jokes here seem particularly out of place. A facility to connect to part of the publisher's Internet site (www.ransom.co.uk) directly from the PDA was not tested. Accessing it from another machine revealed pages still under development but with some additional information in place.

The `Thinking' section contains multiple choice tests designed for different levels. The questions are selected from small banks of items so the tests do not repeat exactly. Each question is marked immediately but without additional feedback. Most of the information needed can be found in the glossary or elsewhere. Clicking on the central feature of the menu screen reveals a randomly chosen quotation from an eminent scientist. A separate text-based program contains additional information and worksheets at different levels. Answers, or suggested approaches to open-ended questions, are supplied.

The recommended minimum system specification is a 486DX processor, 8 Mb RAM, 32 000 colours, double-speed CD-ROM drive, Windows 3.x, sound card and speakers. The image size was disappointing, at 600 × 480; pixels, so that on most machines the picture will have a broad black border unless the screen resolution is downgraded. Video from CD-ROM still leaves much to be desired, and this is apparent if the option to display sequences at full image size is chosen. In the PDA in particular the text is small and difficult for someone with poor eyesight to read. The sound quality is good but the music is repetitious and the American accent testifies to the importance of the transatlantic market.

It is very much education through entertainment, and that approach has its limitations: it tends to be simplistic and does not meet the needs of a serious user. The presentation is in an irreverent style which we are led to believe appeals to young people, though their elders may find it patronising. The content provides a good general introduction, a suitable resource for project work or for background information to supplement a more structured course, but it suffers from trying to cover too wide a range of age and aptitude. Two bright teenage boys, while finding it not without interest, reacted very coolly to it.