Teaching Physics

243 Pages·2003·8.306 MB·English

by  Laurence Viennot (auth.), Laurence Viennot (eds.)

TEACHING PHYSICS
Teaching Physics
by
Laurence Viennot
Universite Denis Diderot, Paris, France
with the collaboration of
U go Besson, Franc;oise Chauvet,
Philippe Colin, Colette Hirn-Chaine,
Wanda Kaminski and Sylvie Rainson
Foreword by Guy Aubert
Translation
Amelie Moisy (foreword, introduction, chapter 1 and conclusion)
Malcolm Greenwood (chapters 2 to 6)
Springer Science+Business Media, LLC
A c.I.P. Catalogue record for this book is available from the Library of Congress.
ISBN 978-1-4020-1276-1 ISBN 978-94-010-0121-2 (eBook)
DOI 10.1007/978-94-010-0121-2
Printed an acid-free paper
AU Rights Reserved
© 2003 Springer Science+Business Media New York
Originally published by Kluwer Academic Publishers in 2003
Softcover reprint ofthe hardcover lst edition 2003
No part of this work may be reproduced, stored in a retrieval system, or transmitted
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Table of Contents
ACKNOWLEDGEMENTS IX
ABOUT THE AUTHOR Xl
FOREWORD X111
INTRODUCTION
CHAPTER 1/ Watersheds 7
1. Howand What toSpotlight 7
2. How Much Should beExplained 17
3. Images:Are theyalwaysuseful? 19
4. Experiments: Are theysupposedto help? 27
APPENDIX 1: Some General Intentions Are Very
Similarinthe VariousSyllabuses 35
APPENDIX 2: Whythe Pinhole Camera is no
Longer on theSyllabus 39
CHAPTER2/ Contact,friction andpropulsion 41
1. Laws that Run Counter to Common Sense 41
2. AMethod ofSpotlightingthe Basics 43
3. AWay ofSpotlightingFriction:goals and difficulties 45
4. First Elements ofStatic Friction: step bystep 49
5. Analysing the Sequence: lines ofattention 53
6. Evaluation ofthe Sequencewith Students 55
7. ReactionsofTraineeTeachers 61
8. What Conclusion Should We Draw? 63
APPENDIX 1: The Technique ofFragmented Diagrams 65
APPENDIX 2: Two Situations forStudying Kinetic Friction 70
APPENDIX 3: Trainee Teachers' CommentsontheSequence 71
vi
CHAPTER 3/ Pressure in Fluids in the Presence ofGravity 75
1. Questions About the Merits ofaMicroscopic Approach 75
2. TheMacroscopic Level: what quantities "haveto be"? 78
3. Fluid Statics: common ideas among students 79
4. AProposal for the Teachingof Fluid Statics 86
5. Analysing the Sequence: lines of attention 98
6. Evaluation of the Sequence with Students 100
7. Teachers' Reactions 109
8. Conclusion 111
APPENDIX: Main Results of the External Evaluation 116
CHAPTER4/ Superposition ofElectric Fields 121
1. Interaction at aDistance and Superposition 121
2. Charges, Fields and Superposition: selected aspects 124
3. Superposition and Causality:common forms of
reasoning 125
4. Elements of aTeachingSequence 131
5. Analysing the Sequence: lines ofattention 133
6. Evaluation ofthe Sequence 134
7. Conclusion 141
APPENDIX 1: Contents Previously Taughtto Students
Questioned inthe PreliminarySurvey 144
APPENDIX 2: Electrostatics and Electric Circuits
Disconnected: the field in wires 145
vii
CHAPTER 5/ Superposition ofWaves and Optical Imaging 147
I. Choosing aModel 147
2. Common Difficulties and "Spotlighting" ofthe
Content 149
3. Analysingthe Proposal: someelements 164
4. Reactions of In-Service or TraineeTeachers 169
5. Conclusion 176
CHAPTER 6/ Colour Phenomena 181
1. A Topic at a Crossroads 181
2. ColourPhenomenaand Light:the chosen approach 182
3. Common Ideas:too exclusivea linkage 183
4. A Proposed Sequence 185
5. More Detail, Followingthe Lines of Attention 188
6. Evaluation ofthe Sequence 191
7. Teachers' Reactions 196
8. Conclusion 201
APPENDIX I: Additive and SubtractiveMixing 203
APPENDIX 2: Aspects ofKnowledge Whose Acquisition
isEvaluated One Yearafterthe Sequence 204
CONCLUSION 207
BffiLIOGRAPHY 221
INDEX OF NAMES 233
Acknowledgments
I have been very fortunate in being able to work with Ugo
Besson, Francoise Chauvet, Philippe Colin, Colette Him-Chaine,
Wanda Kaminski and Sylvie Rainson. Their studies form the
body of this book. My thanks are due to them for everything they
have contributed, to this book and beyond. Thanks, too, to the
students who were kind enough to take part in our investigations
and to the teachers, both beginners and experienced, who agreed
to contribute their thoughts to our discussions. Warm thanks are
also due to our colleagues at the University of Paris 7, especially
to Bernard Perrin, Martin Devaud and Frederick Bernardot, for
their interest and encouragement.
Discussions in the European partner teams involved in the
Science Teacher Training in an Information Society research
project (1997-2001, DG XII, project SOE2-CT-97 20 20) also
made a valuable contribution to this work: sincere thanks to
everyone concerned (leaders of the other partner working parties:
Roser Pinto (Autonomous University of Barcelona), Elena Sassi
(Federico II University, Naples), Jon Ogborn (Institute of
Physics, London), Andreas Quale (University of Oslo».
My warmest appreciation to the translators of this book,
Amelie Moisy and Malcolm Greenwood.
About the author
Laurence Viennot is Professor at Denis Diderot University
(Paris 7), where she teaches physics. She heads a post-graduate
studies programme (DEA) in Didactics of Scientific Disciplines
in the Doctoral School of Scientific Knowledge and also teaches
there and in various teacher training units. This book is based
mainly on work carried out by herself and her research team
(Laboratoire de Didactique des Sciences Physiques).
Foreword
Everywhere in the world, except, for the time being, in some Asian
countries, young people are losing interest in science. This
disenchantment with science studies is particularly strong in the United
States, but has affected Europe, and France especially. Official statistics
confirm this, and I can add a telling example of my own. When I began
teaching physics at Grenoble University in 1960, there were some 350
students studying to be electrical engineers. Today, 57 students are
enrolled in the Physics Maitrise programme at the Joseph Fourier
University in Grenoble, and 15 of them are foreign students. In that time
interval, the total number of students enrolled in institutes of higher
learning in mainland France rose from 309 700 (in 1960-1961) to 2 111
100 (in 2000-2001). If we look at what happened in the USA, to try to
avoid making the same mistakes, there is indeed a strongly antiscientific
trend in that society, of which the "Politically Correct Movement" is the
most extreme manifestation. Yet this movement has profoundly
influenced the humanities departments of American universities, and the
persons responsible for training teachers. There is a risk that similar
negative effects will show up in France, where many primary school
teachers have a background in the humanities, and often have no
scientific culture at all. c.P. Snow's famous pamphlet on the "two
cultures" was published in 1959, but is still exceedingly topical and should
be recommended reading in all teacher training institutes.
This situation will no doubt give pause to all those citizens who feel
concerned by the future of the society in which their children will live
and, obviously, to those whose profession is to teach physics. Could they
be responsible? Could itbethat they did such a badjob of it that they put
ever greater numbers of secondary school pupils off studying science at
xiv
university? Why is it that the few students who do go on to study physics
seem so "hopeless" at it? Teaching Physics provides answers to these
questions, even though its author, my dear university colleague Laurence
Viennot, does not explicitly refer to the context I mention in this
preface. Laurence Viennot and her collaborators have already made great
contributions to the exceedingly complex and controversial subject of
physics teaching, with, most notably, Reasoning in Physics: The Part of
Common Sense, published in 19961
•
Teaching Physics is intended primarily for teachers who are specialists
in that subject, but it is written in such a "fluent" style (to use a word
suggested by the author's introduction) that non-specialists and non
teachers will find it easy to read. The first chapter is absolutely riveting,
and gives the keynote for the five others, which can be read in any order
the reader wishes. One need not have a degree in physics to profit from
that first chapter, since it deals mainly with the teaching of optics in
Quatrieme', On reading it, many readers will no doubt exclaim: "Now I
get it!"(words that come back again and again in this book) - and besides
having understood a little optics, they will have truly understood the
impact of the chosen teaching method, of the (typically French)
dictatorship of the syllabus, with its detailed instructions, of the
experimental approach, and so on.
The following chapters deal with fundamental areas of physics, all of
which are notoriously difficult to teach, for several reasons, when the
goal of teaching is to trigger that heavenly state of "Now I get it!"
Especially illuminating are the dialogues between the "guinea pigs" on
whom the ideas and suggestions of Laurence Viennot and her
collaborators were tested, for - and this is not its least original feature
this book shows how rewarding the experimental approach can be in
didactics. Each chapter provides an innovative contribution to the topic
it deals with. Without minimising the importance of the other chapters,
my personal preference goes to the mesoscopic approach to pressure in
fluids, which is an excellent illustration ofthe possibilities and limits of a
model.
Moreover, having read the chapter entitled "Superposition of waves
and optical imagery", I will indulge in an iconoclastic remark on how
physics is taught in schools preparing students for competitive
examinations in France. Their main goal - and I do not blame teachers
for this - is to make sure that students know how to "do" the
I English translation 2001.
2 The third year ofsecondary schooling inFrance.