Table of contents

Honorary Editor

Peter Gill is a member of the mathematics department at King's College London and teaches basic mathematics to university students who have started degree courses in such fields as chemistry, engineering and physics. In his talk to the IoP Education Group Annual Conference in Leeds (see Phys. Educ. 32 208) he remarked that the most significant indicators of later mathematical competence within their subject areas were confidence at using fractions and in analysing and interpreting graphs. It may or may not come as a surprise to readers that nowadays many universities have instituted such `remedial mathematics' courses for first-year undergraduates, or that many of their students have difficulty with handling fractions.

I'd guess that physics teachers at all levels tend to find it hard to understand why other people find such basic maths difficult. They would themselves have little problem with adding 1/3 to 1/5 to get 8/15. But when did they last have to do this - for real, I mean? In the real world both teachers and their students are far more likely to be faced with adding 33% to 20%, say, which is a much easier task. Adding another 12% to get the total of 65% would stretch few of us, even first-year undergraduates of chemistry and engineering. But adding 3/25 to 8/15 to get (and here I turn to paper and pencil) -19/75 requires a competence in mathematics that took Peter Gill several weeks to instil in his students.

So what use are `fractions'? Of course, percentages are fractions too, and the world of commerce and high finance uses these almost exclusively to quote and use interest rates and calculate VAT (it is easier to add 17.5% than 7/40ths after all). Primary school pupils are taught good old-fashioned fractions still, and are still no doubt expected, with almost inhuman generosity, to share out an imaginary cake into equal-sized pieces. Whether they actually put any of this mathematics into practice I doubt.

A good rule of thumb for the kind of mixture of skill, knowledge and understanding required for successful mathematical operations is use it or lose it. We went `decimal' a long time ago, and the ideas of pence as 12ths of a shilling and shillings as 20ths of a pound are positively mediaeval for everyone under 40 or so. Remember farthings? In those days fractions were everywhere. Nowadays they are somewhat esoteric for the average citizen - and physicist.

Yet fractions are vital in advanced mathematics, e.g. involving the differentiation and integration of polynomial fractions, as Peter Gill pointed out. This is why he was teaching simple fractions to his students, and possibly why their competence at these was such a good indicator of success in their end-of-year mathematics exam. What can we conclude from all this? I suggest two things.

First, that fractions as illustrated above might well be considered as advanced mathematics, a fit and intriguing topic for an A-level course. Ordinary citizens should be taught - very thoroughly - to understand and use that useful kind of fraction based on dividing things into 100 parts, called percentages. Secondly, and more fundamentally, we should learn from this example to take a hard look at what we teach and what we need to teach, removing or adapting those things that exist in syllabuses and the National Curriculum for reasons of purely historical inertia. I hope that the IoP Working Party on Mathematics and Physics, due to report in the autumn, has looked hard at issues like this. And, of course, anyone interested in this topic is cordially invited to the Education Group's 16 - 19 Day Conference, which this year is about this vexed question of what mathematics physics learners need - and how they get it.

At IoP Headquarters on Saturday, 15 November 1997. Details from Catherine Wilson.

By mid-May the UK Universities and Colleges Admissions Service had received a record 409 318 applications for higher education places in the autumn of 1997 (or in 1998 for those planning a year out before commencing their courses). Of these, science applications had increased by 9.7% in Biochemistry, 8.5% in Physics, 2.4% in Biology and 1.9% in Chemistry. Applications for teacher training had fallen by about 11% and there were also fewer applications for civil, electronic and mechanical engineering.

In June came news of the 1996 US Bachelor's degree recipients in a report published by the American Institute of Physics. This indicated that the number of undergraduates receiving bachelor's degrees in physics continued to decline in 1996, falling 2% from the previous year. It appears that such declines may continue for at least another two years. Interestingly the drop at departments with physics graduate programmes has been much greater than at departments which offer only an undergraduate degree in physics.

Median starting salary for 1996 physics graduates in permanent full-time jobs was $31000. Almost two thirds of these graduates who entered the jobs market intended to pursue advanced study in the future, with one third intending to enter a graduate physics programme. Interestingly, one third of the 1996 physics graduates began their college studies in another discipline, but when it comes to graduate study, an increasing proportion of physicists choose to study interdisciplinary subjects such as medical and health physics.

Since late 1995 both the American Physical Society and the American Association of Physics Teachers have been addressing the need for better science education in the USA through the Campaign for Physics. This comprises five interrelated programmes to improve the teaching, learning and application of the physical sciences from kindergarten to graduate school. The `Teacher - Scientist alliance institute' is designed to support hands-on inquiry-based teaching of science at elementary level, whilst the Physics Teacher resource agent programme is intended to train and support experienced physics teachers who serve as mentors to less experienced colleagues within their communities. An on-line and hard-copy collection of teaching and learning materials in physics for high school and undergraduate levels is being planned in the form of a Physical Science resource center, and the Minority Scholarship programme provides guidance, encouragement and financial support for talented minority students. The last of the five initiatives covers Academic - Industrial - Government roundtables, with the aim of promoting a shared perspective among the three communities on the USA's research and education needs.

More information on the Campaign for Physics can be obtained from the Campaign Director, Darlene Logan, American Physical Society, One Physics Ellipse, College Park, MD 20740-3844, USA.

May of this year saw the establishment of the Science Engineering Technology and Mathematics Network (SETNET), a UK body aiming to ensure that young people are positively encouraged to take science, mathematics and technology courses in their schools or colleges and to consider careers in engineering. SETNET will develop a nationwide framework of policy and collaboration so that providers of information can work together rather than in isolation. The emphasis will be on science, mathematics and technology as key curriculum subjects, as well as the promotion of positive experiences of industry for students.

SETNET will function through up to 30 SETPOINTS throughout the UK, which will act as a focus for business, industry and teachers by providing access to relevant comprehensive information. Cooperation will be encouraged through joint events and projects, reviews of local activities will be undertaken and gaps in the information available (as well as duplication) will be highlighted. It is anticipated that business and industry are more likely to see more involvement in schemes and resources when teachers are using SETPOINTS as `centres of excellence', gaining access to other professionals and receiving advice on the appropriateness of products.

The SETNET information service can be accessed by calling 0171 380 0562 (e-mail: setnetwork@aol.com) or by post to the Science Engineering Technology and Mathematics Network, Freepost, 369 Euston Road, London NW1 3AR. A unique WWW site is to be set up in the near future.

Part of an autumn mailing to UK schools from the Institute of Physics Education Department will be a smart glossy booklet for 14 - 15 year-olds entitled ` Smart moves'. This is intended to get appropriate messages and images of physics across to young people, and copies will be supplied for school physics departments and careers areas. Details on how to obtain additional copies will also be included in the mailing.

Readers of Physics Education may already be aware of the Flexible Learning Approach to Physics (FLAP) project, designed to help students make the transition from school/college to university and to broaden access to physics courses in higher education. A huge package of high quality supported self-study, student-centred learning materials covering physics and its associated mathematics, from a level just above GCSE to a point within the first year of a degree course in physics or engineering has been developed, and is now available to UK schools and colleges. The materials range from single photocopiable modules (at £5), through specially selected schools physics and maths starter packs (£70 and £50 respectively) to full sets of over 100 items including audio cassettes and videotapes for around £800. Dr Stuart Windsor, FLAP Project Coordinator in the Physics Department at the Open University, Walton Hall, Milton Keynes MK7 6AA (tel: 01908 654083 or on the Internet at http://yan.open.ac.uk/flap) is the contact for further information.

Support for students and teachers will be the basis for an event to take place at the 1998 Institute of Physics Annual Congress in Brighton next March. It will take the form of a `Physics in action' hands-on exhibition on all three days of the meeting, with activities biased towards Key Stage 3. Mary Wood of the Institute's Education Department is interested in developing resources or activities with teachers and their students for the exhibition, and would be delighted to hear from anyone willing to participate. She can be contacted at the Education Department, The Institute of Physics, 76 Portland Place, London W1N 4AA (tel: 0171 470 4800, fax: 0171 470 4848).

A unique teaching resource which provides all the items required for teaching electrophysiological measurements through practical demonstration has been developed at the Royal Hallamshire Hospital, Sheffield. The key elements in the Body Electric kit are:

• a physiological amplifier which can connect to any IBM-PC computer

• software for acquiring, storing and processing data

• a manual of practical experiments

• lecture material and notes

One of the problems of making physiological measurements in schools is that they cannot be made safely using standard laboratory equipment. The Body Electric kit contains an isolated amplifier which connects to the parallel port of any IBM-PC computer, allowing the electrical activity of the heart - the ECG (figure 1) - and the electrical activity of muscles - the EMG (figure 2) - to be safely recorded and displayed. The data acquisition and processing software included in the kit is menu driven and provides context-sensitive help facilities; the manual describes a series of experiments which can either be used as student practicals or classroom demonstrations.

Figure 1. An example screen showing the ECG signal and the heart rate.

Figure 2. Example showing the recording of the EMG signal. The use of the oscilloscope is optional.

To accompany the practical demonstrations, the kit has slides and lecture notes which introduce the key concepts behind measuring and analysing electrophysiological signals. This material has been prepared in Microsoft's PowerPoint presentation manager. In addition to including the material in booklet form which can be copied for classroom use, the lecture material is supplied on disk together with a PowerPoint viewer so that it can be projected directly where facilities are available.

Further details of The Body Electric kit, price £250 1 VAT, can be obtained from Mrs V G Stevens, Department of Medical Physics and Clinical Engineering, Royal Hallamshire Hospital, Sheffield (tel: 0114 271 3675, fax: 0114 271 3404, e-mail: v.g.stevens@sheffield.ac.uk).

Duisburg, Germany, will be the venue for an international conference entitled `Hands-on experiments in physics education' to take place on 23 - 28 August 1998. The conference is being organized by GIREP (the Groupe International de Recherche sur l'Enseignement de la Physique) and supported by ICPE (the International Commission on Physics Education); the conference language will be English.

Planned topics to be covered are: hands-on experiments in school, university, science centres, on television and in the home; physics toys as a form of hands-on experiments; low-cost experiments in relation to hands-on experiments; and educational aspects of hands-on experiments. The deadline for abstracts for papers and/or posters is 13 March 1998, and that for registration alone is 15 May. The local organizing committee will be arranging accommodation in student apartments and hotels at favourable rates for delegates.

Further information may be obtained from Professor Drs G Born, H Harreis or N Treitz at Gerhard-Mercator Universität, FB 10/Sektion Didaktik der Physik, Lotharstr. 1, D-47048 Duisburg, Germany (tel: 0049 203 3792237, fax: 0049 203 3791679, e-mail: hm379kr@uni-duisburg.de) or by examining the conference homepage at http://www.uni-duisburg.de/FB10/DDPH/girep/girepeng.html.

An account of how a single suspended bubble can emit blue light, produce a shock wave similar to Concorde's sonic boom and potentially provide more information about stellar physics than the Hubble Space Telescope gained a first prize in this year's `Science in Print' competition, run by the UK Institute of Physics and the National Physical Laboratory. The author was Jon Heffernan, research scientist at Sharp Laboratories, Oxford, and his prize was £400, with a place on a one-day Media Training Workshop.

The other first prize went to Tom Parker, a research scientist at King's College, London, who wrote a marvellously entertaining and down-to-earth account of life as a research student. This took the form of a diary detailing the high and low spots of laboratory work, and according to the judges even made the study of spontaneous Brillouin scattering interesting! Tom also received £400 and a Media Training Workshop place.

Other winners in the competition examined such topics as crash test dummies, microelectronics and modelling the financial markets. Three students were among the prizewinners: Joshua Winn of the Physics Department at Massachusetts Institute of Technology, for `Moonrise on Cape Ann'; James Niblett of the Physics Department at the University of Cambridge, for `Necessity: the Mother of Wishful Thinking'; and Charles Williams of Biddulph Sixth Form, Stoke-on-Trent, for `Super!'.

This was the fourth year of the competition, which aims to encourage scientists, science teachers and science students to write for the general public. A champagne reception and award luncheon was held for the winners in July at the National Physical Laboratory.

Varied topics and more lectures feature in the 1997 - 8 schools programme announced recently by the UK's Royal Institution. Among the lecture subjects are Electricity, Feathers and Flight and The Earth and the Planets, along with the less serious `Why eskimos don't build skyscrapers' and `The science of ice cream'. Also included will be a week on engineering in support of the Year of Engineering Success, and a special Science, Engineering and Technology (SET) week.

Audiences from Junior level right up to Post-16 will be catered for, and there will be special Teachers' workshops to provide support for classroom work. Full details plus booking forms can be obtained by sending a large (A4) stamped addressed envelope marked `Schools lectures' to the Education Officer at the Royal Institution, 21 Albemarle Street, London W1X 4BS (or see http://www.ri.ac.uk).

Meanwhile funding from the Royal Society and British Association Millennium Awards scheme has been made to various individual scientists, engineers and others who will work in partnership with local groups to bring science alive in the community. Among the successful projects was a demonstration of science through theatre at the Imperial Fringe Theatre Group in London; an illumination and exploration of science, engineering and technology at the medieval church of St Mary Redcliffe in Bristol; and the production of a music documentary in Scotland integrating the science and historical development of iron-working with the history, folklore and culture of the local area.

A second round of award winners should be announced shortly, and the closing dates for future rounds are 31 December 1997, 30 June 1998 and 31 December 1998. Details of the awards scheme are available from the Royal Society, 6 Carlton House Terrace, London SW1Y 5AG (tel: 0171 839 5561, fax: 0171 451 2693, http://www.royalsoc.ac.uk).

The Hertfordshire Science Teaching Scholarship is sponsored jointly by publishers John Murray and biology author, Don Mackean. It is administered by Hertfordshire County Council but is actually open to applicants from all parts of the UK. The bulk of the £7000 sum must be used to fund a teacher's replacement whilst he or she is seconded to work on a project.

Science teachers of at least three years' experience, working in secondary or middle schools or colleges of further education, or teachers in primary or special schools with an interest in science teaching are eligible for the award. The scholarship is intended to give teachers time off to develop a project which will benefit their school, region or science teaching in general. The award can therefore enable a teacher to apply for secondment for one term or an equivalent period of time, as is most convenient. The scholarship will then pay for the teacher's replacement for this period, as well as offering a grant of up to £500 towards travelling or photocopying expenses and the purchase of materials and equipment.

The aim of the project must be to make the teaching of science more effective by producing and testing new ideas, rather than academic research into a science subject or educational theory. Full details and application forms can be obtained from the Science Adviser, Wheathampstead Education Centre, Butterfield Road, Wheathampstead, St Albans, Herts AL4 8PY. The closing date for applications is 1 February 1998.

There are many moves to enliven and interpret physics teaching by incorporating some history of science. However, lack of suitable resources often proves an obstacle for teachers. A workshop at the Science Museum, London, on 6 November 1997 aims to tackle this issue. Organized by the British Society for the History of Science, the workshop will bring together teachers, publishers, examiners, writers and historians to discuss what sorts of resources are available or are needed.

The discussion will focus on material recently produced to mark the centenary of the discovery of the electron. As well as books, articles and the new SATIS style pack, videos, plays and lecture demonstrations will be sampled and discussed.

For further details and registration (likely to be £5) contact Wing-Commander Bennett, British Society for the History of Science, 31 High Street, Stanford in the Vale, Faringdon, Oxon SN7 8LH (tel and fax: 01367 718963, email: bshs@hidex.demon.co.uk).

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

Contents

The new graphical representation of centripetal acceleration E Krupa and W Tanska-Krupa Institute of Physics, University of M Curie-Sklodowska, Poland

Resolving dishcloths N J Weaver Royal Grammar School, Guildford, UK

Pulling your weight? R Marshall Oakham School, Rutland, UK

The basic concepts of quantum mechanics can be introduced at a high school level by considering the action of classical mechanics and then introducing Planck's constant as the granularity of that action. A practical example of the periodic motion of a spring allows students to investigate the limits of classical mechanics, and concepts such as the Uncertainty Principle can be discussed.

The well-known paradox of the space-travelling twins is easily stated, but it is not at all easy to explain, especially to a perspicacious audience. This essay attempts to set out an explanation (largely inspired by Paul Davies' book About Time [1]) which should be within the grasp of an intelligent sixth-former.

New technologies have led to a reassessment of subjects that are suitable for inclusion in introductory physics courses. We no longer need to restrict ourselves to those systems that can be described in terms of simple, well behaved, mathematical models. Multimedia methods, simulation and computer algebra packages have enabled us to tackle problems we would never have considered only two decades ago.

The spectral distribution of blackbody radiation is given by Planck's blackbody equation. This can be integrated across the complete spectrum to obtain the total blackbody emissive power (the Stefan - Boltzmann law). In some circumstances we shall want to investigate behaviour only in a band of the spectrum. For example, rare earth oxides which are commonly used in thermophotovoltaic devices typically emit significantly only in a single narrow band. The complexity of Planck's blackbody equation is such that it appears to require significant computing prowess to be able to obtain useful results. In a recent paper in this journal, Jain (1996) calculated the emissive power of the visible region using the high-powered mathematical software package Mathematica. The requirement of advanced numerical techniques and/or a powerful piece of software limit the range of students who can study spectral blackbody effects. However, by taking a closer look at Planck's equation we find that it is possible to learn much about spectral blackbody effects (including all of Jain's results) by careful use of mathematical techniques covered in A-level and a spreadsheet (or other simple computational tool). This opens a study of Planck's equation to all undergraduates.

The interaction between particles can be pictured as an exchange of virtual particles, but this view creates doubts in many people. Feynman diagrams can help in this but a consideration of fields is important.

In the late 1980s access to Engineering courses in higher education was widened and Foundation Years were introduced. Some pedagogical problems arose due to the unusually heterogeneous groups which ensued. The authors, who were associated with the Science and Engineering Foundation Programme at Loughborough University, which was instigated in 1991, investigated teaching and learning strategies which could be used beneficially with students having wide ranging previous educational experiences. One area which appeared to be very promising was that of Computer Assisted Learning, which could be undertaken by students as and when required. A piece of computer assisted learning and assessment courseware was produced during the academic year 1994 - 5 and evaluated in the following academic year. The responses of the Foundation students with whom the CAL courseware was piloted were generally favourable, and some useful suggestions concerning ways in which the courseware could be improved were made.

Students may manipulate vectors but do they understand them? Teaching using the approach described here should ensure that they do.

Physics teaching needs to become more cost-effective and this could be achieved if methods of teaching and learning were substantially revised from the point of view of the desired objectives, and if teachers recognized the need for continuing professional development in this area.

This paper attempts to consider the aims that undergraduate physics degree courses actually reflect and serve in the light of the employment patterns of graduates and of the expressed needs of employers. It reviews the results of analyses of what degree examinations actually test, and goes on to quote criticisms of their courses and radical proposals to change them adopted by the UK conference of physics professors. The discussion is then broadened by discussion of evidence, about the employment of graduates and about the priorities that some industrialists now give in the qualities that they look for when recruiting new graduates. The evidence leads to a view that radical changes are needed, both in courses and examinations, and that there is a need for university departments to work more closely with employers in re-formulating the aims and priorities in their teaching.

Since the founding of the People's Republic of China, seven major physics syllabi have been used by all secondary schools in China. This essay describes the evolution of these syllabi and analyses the shifts of these syllabi in terms of objectives, contents, instructional hours and teaching methods. Changes for China's future secondary physics education are suggested.

A new degree course specializing in optics has been established at Liverpool John Moores University. Although built on a core of physics, the course has two distinctive features which make it more than just `Physics with Optics'. Firstly the scope is wide, involving light in its many applications. Secondly, the optics flavour is introduced from the outset. Graduates from the course should be well equipped to work in areas requiring both a knowledge of the physics of light and optical devices and an appreciation of their engineering applications.

The sixth volume of Innovations in Science and Technology Education is the latest volume in a series initiated by UNESCO in 1984. This publication can be regarded as one of many contributions to the realization of the goals of the so-called Project 2000+, which is designated as a collaborative venture involving a group of major intergovernmental organizations and agencies, together with non-governmental organizations having special concerns and responsibilities in the field of science and technology education and research.

The general theme of this volume is scientific and technological literacy (STL) as a current phenomenon/movement aimed at broadening the scope of science and technology education (formal, informal and non-formal) to make science and technology available to the whole population. The task is very difficult but from the viewpoint of worldwide needs very desirable. Complex problems related to STL are subjected to thorough discussion within 11 comprehensive essays written by authors from various cultural and geographical areas. The representative and successful selection of the essays was performed by Edgar W Jenkins, editor of the volume.

The publication is divided into three parts. The introductory chapter offers an overview of the rationale, meanings and measures associated with STL and the second section contains a range of theoretical perspectives. The two parts provide a conceptual framework for the country-specific STL studies which constitute the third and concluding chapter.

The book is primarily intended for science educators in universities and colleges, especially those involved with teacher training and curriculum planning, Ministry of Education officials and practising science and technology teachers. Also non-specialists may find interesting sections in this volume, especially in its third chapter which contains recent data from the educational practices of various countries. Owing to the special terms and the sociological and philosophical tone of many passages the book will not be beneficial to younger students.

This is the latest of the books that aim to cover the requirements of the major A-level syllabuses. The circular sticker on the front cover advertises that the book covers 100% of the new A-level Core published by SCAA in 1997. The authors state the aim of the book in the first three sentences addressed to the student: `This book gives you a thorough coverage of the core material for advanced physics courses. It also includes the main optional topics of examination syllabuses. It has been written to convey the excitement and immediacy of modern physics and its uses in real-life situations, in the hope that you will develop an enthusiasm for physics, and gain the basic tools for a possible future physics career'. This is a significant task to achieve with sufficient depth in only 700 pages.

The material is divided into seven sections. The first four: Forces, Movement and Materials, Charge: Current and Fields, Thermal Physics and Waves, Quanta and Atoms cover the subject core. The introductions to each section link with GCSE balanced science. The other sections cover the option units of many of the syllabuses. These sections are entitled: Physics for Control and Communication, Human Physics and Physics at the Edge.

Each chapter begins with an `Opener' describing an often familiar example of the way that an aspect of the physics in the chapter is used. A brief overview describes the physics developed in the chapter where key words and ideas are printed in bold. Full colour is used throughout in photographs and diagrams. Coloured tinted backgrounds indicate feature boxes (which describe modern applications of science or historical developments), extension passages (which extend the basic concepts to a more advanced level) and in the margin self-test questions and reminders of/cross-references to other parts of the text.

Other regular features of each chapter include a summary of the main points, more questions and an `assignment' - typically a self-contained extension exercise with information about an application of physics which can include real data to analyse. Finally each chapter or group of chapters has a map, a diagram of linked boxes enclosing the main concepts covered, showing how these are interrelated. Finally there are several appendices including three pages of data and relationships, a seven page summary of mathematics for physics, answers to numerical questions and a comprehensive index of over 3500 entries. The format of the book is therefore very similar to a number of its competitors.

The first section opens with a chapter entitled `Moving in Space and Time'. The student is immediately reading about measuring distances using electromagnetic waves, from an astronomical scale to Earth-bound triangulation. There are feature boxes on `satellites for surveying' and `light and astronomical distances'. Next kinematics is introduced through the use of the Doppler effect to measure the speed of a vehicle. The basic equations of motion are then developed. Two pages on frames of reference lead into a section on vector addition and finally the equations of motion are developed a second time in a tinted box using calculus methods. After the summary and questions, the authors have designed an assignment using a spreadsheet to investigate uniformly accelerated motion. In the simulation the student generates the data which can then be displayed graphically.

This first chapter has been described in detail as it is a typical example of the pattern of most chapters. The authors have thought clearly about designing each topic to be interesting and original in its approach but still maintaining the core physics concepts at the heart of the material. Often such an approach is more attractive to the teacher, who appreciates the subtlety of thought that has gone into the design. The student can prefer a more basic bold approach where the important facts alone stare out of the page at him or her without any frills. The authors appear to have achieved a good mix in the design and layout to satisfy all types of students. Hopefully the `quick fix' student will be enticed into reading further and become more interested in the applications. There is no doubt that the major use of coloured background tints makes it easy to move round the book quickly recognizing which is main text, application, mathematical exposition, etc. The use of three or four colours for each diagram enables features to be highlighted or recognized easily. A typical simple example is the graph of the Maxwell--Boltzmann speed distribution of the molecules of a gas shown at four different temperatures. Each curve is a different colour so the eye instantly recognizes the change in shape without confusing the curves. In monotone such a diagram takes a significant time to unravel. Another colour feature of the book is a band about 1 cm wide down the outside edge of the first left-hand edge of each chapter. Each of the major sections is colour coded so a chapter in a section can be located quickly by just looking at the edge of the book as it lies open. A 2 mm square coloured box next to the page number carries the same coded message.

The depth of treatment of each subject is good considering the amount of material which has to be packed into 700 pages. No page looks overcrowded with text or diagrams - there are still open white spaces, to give the text some freedom. The level of language is satisfactory. Technical words are always used, being introduced in bold on the first occasion or where they are referred to in the index. Sentences are short, simple and unambiguous. I would not expect many students to be able to read, learn and understand many of the principles and techniques without also being taught in class. For example, in the chapter on alternating currents and electrical power, reactance, impedance, LC, LRC and power in a reactive circuit including phasor analysis are all covered in eight pages. This also includes an information box on filter circuits and an example of a woofer and tweeter with crossover. The exposition is clear but very concise.

To return to the subject matter, the section on forces, movement and materials takes up almost one third (200 pages) of the book with chapters on dynamics, gravity including field and potential, balanced forces and materials, oscillations and mechanical waves, the states of matter including structure and microstructure and kinetic theory, and finally transport which includes conservation laws, rotation, collisions, fluid motion, pressure, viscosity, etc. The chapter map on transport, for example, is a very useful guide to see how the main ideas connected with the movement of solid objects and of fluids have been linked together. The next section on current and static electricity covers another 100 pages. The chapter on circuits and charge is followed by one on electric field and potential; then electromagnetism followed by electromagnetic induction and finally a chapter on a.c. theory and electrical power. The section on thermal physics is quite short, only two chapters, firstly on temperature, thermal capacity and conduction and secondly a neat exposition covering the four laws of thermodynamics with application of the first law to an ideal gas followed by a microscopic approach to introduce entropy. The chapter finishes macroscopically with heat engines, pumps, etc. Waves, Quanta and Atoms is the last core section covering another 100 pages, containing chapters on electromagnetic radiation, atoms spectra and quanta, the atomic nucleus and lastly imaging. This chapter passes from lens optics to mirrors, telescopes and microscopes, the eye, camera and finally a few paragraphs covering ultrasound probes to the electron microscope - a marriage of topics both `ancient and modern'. The full colour pictures and multicoloured ray diagrams make an attractive package and one that is easy to browse through.

The first of the three option sections begins with some solid state physics, including p - n junctions, superconductivity and magnetic materials. The next chapter looks at communication systems using e-m waves and the third covers physical electronics, both digital and analogue. This section seemed to be poor on examples of modern electronics, with no mention of CDs or CD players, for example. Human Physics consists of an unusual marriage of topics, the first a chapter on Earth Science and the energy balance related to the effect of the atmosphere followed by a chapter on Medical Physics - effectively and concisely described with vivid colour illustrations and charts. Again the content has to be brief, being only 17 pages, when compared to the monographs available on this subject. Physics at the Edge starts with a chapter on relativity followed by one on subatomic particles covering all the main concepts of a particle physics option course. The theme then expands to astrophysics, concluding with a chapter on cosmology.

The authors have created a very significant physics package in this book, successfully covering a vast number of topics. A minor criticism is that some diagrams are too crowded with information. In some places too, the text attempts to include too much information in too small a space. Although IT has featured in assignments through the use of spreadsheets, the authors do not deny that the student will have to look elsewhere for practical work as experiments are given but brief mention in the text. Also other sources will be needed for a greater in-depth treatment of any of the topics covered. However, the two-page summary on the Big Bang model of the Universe is a perfect example of what can be done in a small space, including its half-page logarithmic graph in six colours, packed with information. This is a book to be considered seriously when teachers are looking for a new base textbook. Several copies should at least find their way onto the Science Library shelves to be used as a mine of useful information. It remains to be seen whether the consumer, the student, finds the material too dense to be used as a reader as well as a reference.

In a recent issue of Physics World ( 10 (5) p57) Catherine Wilson suggested seven possible reasons for the decline in the number of students taking A-level physics in England and Wales. Could Robert Ehrlich add three more? He suggests that physics is often thought to be highly abstract, user-unfriendly and remote from everyday life. If this is true, physics teachers at all levels must share some of the blame. Have our demonstrations embraced accuracy, precision and sophistication at the expense of `wonder and delight'? Ehrlich might reply that `Using `low-tech' items which you can work with at home makes physics more relevant to everyday life, and it humanizes it - while doing experiments with complex apparatus may have just the opposite effect.'

Aiming at both experienced and novice demonstrators the first chapter explains how to design your own simple physics demonstrations. Look around for good ideas - and this book is full of them - but go on to develop and `improve on existing demos and customise them for your own needs.' By designing your own demos you will understand them and the physics behind them better and be more likely to use them with classes. `Best of all you will not fear that your demos will more likely illustrate Murphy's Laws rather than Newton's!' In summary Ehrlich enunciates three basic criteria for the design of good physics demonstrations: (1) Keep them simple, (2) Keep them pedagogically sound and (3) Get the physics right. Each of these principles is expanded and illustrated with appropriate examples.

Chapter 1, then, is a succinct, instructive and amusing course in the Art of the Successful Physics Demonstration. But there are 11 more chapters, and it is in them that the earlier theory is used in demos so fascinating that they will have readers turning their houses upside down to find the bits and pieces needed to try them out. Many of the experiments will be familiar, in some form or other, to all physics teachers. So what's new? Firstly the equipment is simple. No computers (except to search the World Wide Web for ideas). No oscilloscopes. No air tracks. No black boxes - well maybe a digital thermometer (in Fahrenheit!) and a digital scale (accurate to 0.1 g). British readers might find the mixture of British and metric units and the use of some American terminology a bit odd! But I digress.

Although most of the apparatus is readily available, not every home will contain a 1 farad capacitor and a hand-crank generator! Which is a pity as I found this demonstration one of the most fascinating - and it works well even with a much smaller capacitor. Simply charge the capacitor with the hand dynamo and let go. But first ask the audience to predict what will happen when you let go - and why! Simplicity, good pedagogy and scope for some good physics.

Ehrlich's work differs from many other popular books of DIY experiments in that he often gives not only qualitative but also clear quantitative descriptions of his demonstrations. For his analyses he uses mathematics which does not go beyond sixth form level. In general the experimental results are in reasonable agreement with the theoretical prediction. Naturally a toy car running along `a ruler which rests on stick pens' or along `a piece of lucite resting on a bunch of BB's' will not yield quantitative results comparable to those obtained with an air track and digital photo timer and you might expect that a `quarter and a nickel' colliding on a table would hardly produce good quantitative results. Ehrlich, however, claims that his simple coin demo `yielded consistency with momentum conservation to within a few percent'. I would have been happy to be able to say that about many dry ice puck collisions!

Among the well known problems which receive both a qualitative and a quantitative analysis are the following. When would you add cream to your coffee to ensure that it will stay warm longer? Does the weight of an hourglass change as the sand flows? And, of course, why does toast land jelly-side down? You have no doubt built a Hero's engine from a soda (Coke!) can but can you derive an expression for the time taken for one revolution from rest? Further, can you use the same can as an anti-Hero's engine, i.e. one which turns in the opposite direction? Buy the book!

Over 100 demonstrations are described, with mechanics taking the pride of place and current electricity, alas, being the poor relation. The final chapter deals with simulations of modern physics such as nuclear fusion, time dilation, the Michelson - Morley experiment and the expanding universe. There is also a quantum-mechanical tunnelling analogy. Many of the demos can be conducted on an overhead projector. In fact some are designed specifically for that purpose, which makes them particularly suitable for large audiences as well as physics classes. As most of the equipment should be fairly easily obtained from local stores, toyshops or school science departments many of the demonstrations could be ideal for lectures on the Public Understanding of Science.

`Gee-whizz' demos

Memorable demonstrations which capture the imagination of the audience are of great value and will long be remembered. But would-be demonstrators are warned `against dramatic `Gee-whizz' demos which may entertain and even put a human face on physics but may not result in much learning and may even reinforce misconceptions.'

One example of a good entertaining demonstration which does not come into the last category is based on a stunt first suggested in the 1926 issue of a magicians' journal. A light and a heavy mass (such as a matchbook and a bunch of keys) are tied to opposite ends of a 1 metre long string which is passed over a pencil. The keys hang straight down a few centimetres below the pencil while the matchbook is held so that the string is nearly horizontal. What do you predict will happen when the matchbook is released? Wlll the keys strike the floor? A qualitative answer and some hints on how to tackle a quantitative solution are given.

Another demonstration certain to cause interest and capable of a rigorous quantitative analysis involves dropping two identical toilet rolls while holding on to the sheet at the end of one of them. They hit the floor at the same instant if their initial heights have a specific ratio. A worked example is given using the ratio of the diameter of the hole to the diameter of the roll as 0.38. The ratio of the initial heights is then calculated as 0.64 - a figure close to the practical result.

Warning

This is an excellent source book of ideas, not a detailed instruction manual. lt is therefore essential for demonstrators to try out the suggested demos with, if necessary, a range of different materials to make sure they get the most satisfactory results. For example, American eggs apparently float on water and can be made to rise up against a stream of water from a tap. Scottish hens lay a denser variety which don't float but can be made to rise up from the bottom of a glass. However, they will only come right up into the stream if the diameter of the glass is not much greater than the maximum diameter of the egg. See what I mean? From attempting this and many of the other demos I can confirm that Murphy is very much alive and active this side of the pond.

You are reading an article and you come across a concept which you need explained quickly before you continue. What do you do? The authors of this work would like you to reach for their book. Inspired by the lack of good scientific reference books, it sets out to rectify this deficiency at one fell swoop. The publicity blurb boldly states that the Science Handbook is ` The Resource for basic scientific facts - a must for students, science writers, and anyone who just wants to understand what they read in the newspaper'.

As well as aiming at a variety of audiences, it covers a broad range of subjects with sections on biology, physics, chemistry, geology and mathematics as well as introductory sections on units, conversions and scientific prefixes and suffixes. Coverage is variable with biology (77 pages) receiving seven times as much space as geology (11 pages), while physics weighs in at 32 pages.

The approach is a marriage of textbook and reference book, employing a large number of tables with short, explanatory paragraphs and definitions. Unfortunately the marriage is not a happy one. There is not enough context or explanation for a textbook and it lacks worked examples; however, it does not have the depth of coverage or the ease of use of a reference book. Indeed, there is one fundamental problem with using The Science Handbook for reference: there is no index. One is left to scan through section contents lists to find the relevant few pages and then to flick through these looking for the required information. There are many cheaper reference books available which cover more material and are easier to use.

Given the relatively small amount of space for each subject, the level varies widely from simple, introductory concepts to undergraduate material. For example, the section on electricity and magnetism starts `There are two types of electric charges ( sic): positive and negative.' Fair enough, but further on in the section we have scalar and vector products used in equations and definitions. There is not enough material at any one level to recommend the book to students unless they need a quick reminder of work that they have already covered. In addition, the wide range of levels of information will mean that the `interested general reader' will find the book difficult to cope with.

The style is chatty and admirably attempts a more relaxed approach to scientific reference material with some nice touches but it sometimes comes over like a teacher attempting to be `cool', to interest difficult pupils. One feature I do like is the use of quotations at the foot of many of the pages. These include a quotation from Kierkegaard contrasted with one from Madonna on the facing page. On occasion, however, the chatty style is rather glib, as if the writers had had a few drinks and were becoming a little too garrulous. Examples include the statement that `taxonomy is boring' which may or may not be true but it seems an unnecessary comment in this context and: `There are two tricks to science. First, try to sound intelligent, even if you don't know what you are doing. Second, if you don't know what you are doing, do it neatly and safely'.

Another key problem with The Science Handbook is its inconsistencies and inaccuracies. For example, in the mathematics section, π is defined as `3.141592654...', while in the physics section it is defined as `3.14'. More fundamental is the error in the statement of Coulomb's Law with an equation which gives the force between two charges as inversely proportional to the distance between them rather than inversely proportional to the square of the distance between them. The book also suffers from a distinct lack of good definitions. For example `wave function' appears in the text without explanation, as does Δ to indicate a change.

The Science Handbook is aimed at a wide cross-section of people but fails to meet the needs of any of them. The lack of an index and depth of information makes it unsuitable as a dip-in reference book while the lack of explanations and context mean it is of little use to people without some specific subject knowledge. While the style and use of quotations are fun, they can never make up for the inaccuracies and lack of explanations. Whatever your scientific reference needs, this is unlikely to be the book for you.

R Mike Mullane is a US astronaut who has flown into space three times on the Space Shuttle. He resigned from NASA in 1990 and has since pursued a career as a professional speaker and author. Do Your Ears Pop in Space? is his third book, and is based on the simple idea of writing down the 500 questions he is most frequently asked, answering them simply and straightforwardly, and then presenting the resulting text, together with some black and white photos, in nine sensibly themed chapters. The book did not look particularly appealing when I first received it; the cover was cheerful but cheap, the pictures were small and grainy, and the work was classified by its publisher as `science/trivia' - hardly the thing for a busy professional scientist. However, having read the book I am completely won over by it. I recommend it strongly to anyone with even the slightest interest in space flight, and I recommend it even more strongly to anyone without any interest in space flight. Readers of all ages, with or without a technical background, will enjoy it and will learn much from it. I still think the pictures are grainy and that the cover looks cheap, but I am now in a mood to blame both of those faults on the publisher. Having given me such a good read, R Mike Mullane can do no wrong in my eyes.

The book got off to a good start, as far as I am concerned, by having a first chapter entitled `Space Physics.' This not only covers the basics you would expect (`why are astronauts weightless?' and `how can you steer the shuttle when there's no air' etc), it also gets into the practicalities of launching the shuttle (`why does the shuttle roll after lift-off?'), the principles of orbital dynamics (`can geosynchronous satellites be placed anywhere over the Earth?') and even the factors affecting the visibility of orbiting satellites from Earth (`what is the best way to watch for satellites from Earth?'). One highlight of this chapter that may help some teachers of physics to enliven lessons about uniform acceleration is Mullane's short description of a 430 foot hole in the ground in Cleveland, Ohio. NASA researchers use high speed instrumentation to record the way equipment responds to weightlessness for the five seconds that it takes to fall down this evacuated shaft. Ten seconds of weightlessness can be produced by initially launching the equipment upwards from the base of the shaft, using jets of compressed air. (Those seeking more information on microgravity research can also consult the July 1997 issue of the popular newsstand magazine Spaceflight.)

Subjects covered in later chapters include: Space Shuttle Operations (Pre-Mission, Launch and Orbital), Life in Space, Space Physiology, Reentry and Landing, and the Challenger disaster. All are well treated, and in each case the sequence of questions has been carefully arranged to avoid too much overlap or repetition amongst the answers. The penultimate chapter, which is devoted to `Astronaut Facts', is particularly good. Though eclectic (and hence `trivial'), it is none the worse for that. Its treatment of topics such as `how are astronauts selected?', `can astronauts buy life insurance?' and `how much do astronauts get paid?' neatly counterbalances some of the more `systems' oriented chapters in the earlier part of the book.

Excellence of the questions notwithstanding, the main cause of my enthusiasm for this book remains the style of the answers. Mullane's blend of clarity and forthrightness, lightened by occasional touches of humour, is a delight to read. When it comes to life on board the Shuttle, his simple unhurried sentences convey the feeling of `being there' as well as anything else I have read and far better than pages of unduly purple prose could ever do. This is spaceflight for real - dried vomit on the controls, and all. The down-to-earth prose is part of the otherworldly magic.

This book has some good points and was clearly a labour of love for the author. Unfortunately, I am not able to recommend it to readers of Physics Education. The author sets out to discuss redshift, with particular reference to its importance in astronomy and cosmology. The main text is fairly descriptive, with `mathematical notes' giving a more quantitative treatment. There are separate chapters dealing with the nature of light, the Doppler effect, gravitational redshift, cosmological redshift and unconventional interpretations of redshift. Quite rightly, the author is very firm about the fact that cosmological redshift is not a Doppler shift. So what are the problems?

First, and least important, is the production and presentation of the book. The text is set in a large sans-serif typeface which I found uninviting to read, and the diagrams are highly stylized, often with broad black lines and sometimes with sharp corners where there should be smooth curves, e.g. in graphs of redshift as a function of velocity. The book would benefit from the attentions of a professional editor - there are numerous minor, but irritating, misspellings, inconsistent symbols and proof-reading errors (for example, `Niel' Bohr and `Kirchoff' for Niels Bohr and Kirchhoff; a θ mysteriously becomes a J in mid-derivation; some figure labels are incomplete or misplaced; a vital `exp' is missing from a formula for a Gaussian line profile; megaparsec is abbreviated throughout as mpc (milliparsec) rather than Mpc). Far more serious, though, are the problems with the science.

Despite the author's laudable aim of presenting the `laws of light' and explaining the various distinct ways in which redshifts might arise, the treatment given here has many shortcomings, exemplified by one particularly serious error that occurs in the first chapter. Following some discussion of the origins of special relativity, the author provides an example using regular pulses of light being sent from a moving to a stationary car in which he shows that the time interval between successive pulses being received at the stationary car is longer than the interval between successive pulses being sent from the receding car. However, this has nothing to do with relativity. It is merely a consequence of light travelling at a finite speed and the fact that the observers have measured the time intervals between two different pairs of events. The author seems to have completely missed the crucial relativistic effect, namely that two observers in relative motion will disagree about the time interval between the same two events (e.g. the sending of two light pulses) and that the disagreement depends only on the relative speed and not on whether the two are approaching or receding. The author extends his initial derivation to arrive at what he quite correctly describes as the non-relativistic Doppler effect, but then goes on to reiterate that it illustrates special relativity. Similiar confusions are to be found elsewhere in the book. By no means everything is incorrect, but clarity and physical insight are sadly lacking.

At the beginning, I did refer to `good points', and in fairness to the author I should mention some of them. In the first chapter, there are some good descriptions of early attempts to measure the speed of light (I liked Galileo's, which involved two people some miles apart using buckets to cover and uncover candles). There is a good account of the discovery and interpretation of `nebulae' which led to Hubble's model of the universe and the birth of modern cosmology. The transverse Doppler shift is included. There are some nice diagrams that illustrate the distinction between cosmological and Doppler shifts. The final chapter (on 'unconventional interpretations') makes interesting reading, though it does mix the respectable with the unorthodox. The overall plan of the book is well thought out, and (despite needing an editor) it is written in a readable style. However, these redeeming features do not alter the fact that anyone using this book to study `the laws of light' is likely to end up as confused as the author seems to be.

How to counter the false perception of science as cold facts devoid of human interest is a problem that has exercised many minds in recent years. Richard Brennan presents pen portraits of eight men who have shaped our modern understanding of physics. He writes explicitly for the `intelligent layperson', convinced that the physicists' insights can be explained in simple terms and that their personalities are important in understanding their achievements. It is the dramatic and exciting story of modern physics that he sets out to tell. Seven of the eight are twentieth-century physicists - Einstein, Planck, Rutherford, Bohr, Heisenberg, Feynman and Gell-Mann. The eighth is Newton. His were the ideas that the modern physicists tested up to, and beyond, their limits, but he is included more because of who he is than because the story of his life and work contributes to the main thrust of the book.

To distil the life and work of such important figures into a few short pages is a tall order, and Brennan's success is uneven. The discussion of some concepts, such as simultaneity in the context of Einstein's theory of relativity, is not totally convincing. Only those parts of a subject's work that help to weave a continuous thread through the eight chapters are treated in any detail. The basic concepts of relativity, atomic physics and quantum mechanics have been known for sufficiently long to be more easily accepted, but Feynman's diagrams and the gamut of particles foreshadowed by Gell-Mann's work have not yet been assimilated. Brennan's explanations give some inkling of what they are, but less about how and why they are so important.

The accounts of the lives of the chosen physicists are conventional and pay little attention to the nuances of academic historians. Brennan accepts the story of Newton being inspired by an apple falling because Newton told it to his first biographer many years later. Historians can point to many instances where the recollections of old age are demonstrably incorrect. Brennan does point out that achievements have to be seen in the context of the times, but he does not attain this consistently. He does not always succeed in conveying how reasonable it was that other scientists should not accept immediately ideas like Einstein's relativity, the Rutherford - Bohr atom or Heisenberg's uncertainty.

The personal lives of the eight men are described dispassionately, unpleasant features are neither ignored nor recounted in unnecessary detail. Five of the physicists lived through the Second World War and were radically affected by the conflict: it shattered hitherto close relationships between some of them. It is here one sees most clearly that scientists are not cocooned in ivory towers, but are caught up inextricably in the events surrounding them. The format of the book does not permit an integrated discussion of this vast topic, and in any case it is almost impossible to balance the conflicting pressures of morality, patriotism and reality.

The unashamedly journalistic style of the book ignores many subtleties. Its American origin is obvious, and the author fails to appreciate some cultural distinctions. The description of Faraday as `the Thomas Edison of his day' will seem bizarre to British readers. Where figures are quoted they are in imperial units, which will dismay British science educators. The book is marred by occasional carelessness over details such as the spelling of names. There is a chronology of physics but it is so short that it omits too many significant events, and it gives an unusual date in at least one case (Thomson's discovery of the electron). The glossary is also short and of restricted value, and the bibliography looks as though a page or two has been omitted since it ends at the letter P. The index is not comprehensive, omitting some significant names.

The reader with no background in science should find the book interesting, though there are parts that will not be understood fully. It is more likely to be read by someone with at least a basic knowledge of science, who could find it glib in places. No book of this length intended for a lay audience can do more than skim the surface, and there is a dearth of material about the human side of science. Though imperfect, it is worth using with care, and there is a need for more books of this type.