Reasoning in physics : the part of common sense

247 Pages·2004·9.942 MB·English, French

by  Viennot, Laurence

Reasoning in Physics
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Reasoning in Physics
The Part of Common Sense
by
Laurence Viennot
Université Denis Diderot (Paris 7), France
KLUWER ACADEMIC PUBLISHERS
NEW YORK,BOSTON, DORDRECHT, LONDON, MOSCOW
eBookISBN: 0-306-47636-3
Print ISBN: 0-7923-7140-2
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Table of Contents
ACKNOWLEDGMENTS ix
ABOUT THE AUTHOR xi
PREFACE xiii
INTRODUCTION 1
PART ONE - THE MAIN LINES 5
CHAPTER 1 /Physics: what is essential, whatis natural? 7
1. The Essential: abstraction and coherence 7
2. Common Ways of Thinking in Physics 8
3. Taking “WrongIdeas” Seriously 9
4. Areas ofPhysics and Units ofCommon Knowledge: 10
do they coincide?
5. WhatTo Do in Teaching? 11
CHAPTER 2 / A Trend in Reasoning: materialising the objects of physics 15
1. The Essential in Physics: constructed concepts 15
2. CommonForms ofReasoninginElementaryOptics 16
3. Conclusion 34
APPENDIX 1. Research in Didactics and the New French Syllabus:
Convergences 36
APPENDIX2. Excerptfromthe AccompanyingDocumentforthe
French Syllabus at Grade 8, implementedin 1993 42
CHAPTER 3 / TheReal World: intrinsic quantities 47
1. The Essential: defining a frame ofreference 47
2. Questions: fishes,parachutistsandmovingwalkways 49
3. When Drag Disappears… 52
4. ConsideringNonIntrinsicQuantities: ateachinggoal 57
vi Table of Contents
CHAPTER4/TheEssential: lawsforquantities “at time t” 61
1. Introduction 61
2. Analysingthe Motion ofMaterial Objects:
usual ways ofreasoning 62
3. AnInterpretationofCommonWays ofReasoningin Dynamics 68
4. Coherence and Range ofCommonWays ofReasoning in 70
Dynamics
5. The Stakes inTeaching Dynamics 78
APPENDIX 1. ACauseSituatedin thePast: propulsion by aspring 80
APPENDIX2. WhenthePastLeaves its Mark 82
APPENDIX3. AnalysingInteractions: twosituations 86
APPENDIX4. ExcerptsfromOfficialInstructions ontheCurriculum
ForGrades9and 11 (ScienceSection) 88
CHAPTER5/Quasistatic or Causal Changes in Systems 93
1. TheEssential: systemsthatobey simplelaws 93
2. NaturalReasoning: morestories 95
3. Systems withaClear Spatial Structure 95
4. Systems with No Clear Spatial Structure: examples from
thermodynamics 105
5. LinearCausal ReasoningandQuasistatic Approaches:
irremediabledifferences 114
PARTTWO - THE IMPACTOFCOMMON SENSE
SOME INVESTIGATIONS 119
CHAPTER 6/Quantities, Laws andSign Conventions 121
1. Introduction
2. TheEssential: algebraicquantities andlaws 121
3. The Natural: realityfirst,lawsmust adapt 123
4. Results ofInquiries 124
5. RealisticBalances 126
6. ASuggested Strategy: splitdiagrams 128
7. VerbalStatements: confusionandmisunderstandings 129
8. Conclusion 131
Table of Contents vii
CHAPTER7/Changing Frames of Reference at Eleven 133
1. Introduction 133
2. TheExperiments: principleanddescription 133
3. Main Results andDiscussion 136
4. Conclusion 138
CHAPTER 8 / CommonReasoning About Sound 141
1. Introduction 141
2. Propagation ofSignals in Secondary Teaching 141
3. MainResearchFindingsaboutPulses onRopes 143
4. Propagation ofa Sound Signal 145
5. Conclusion 150
CHAPTER 9/Constants andFunctionalReduction 153
1. Introduction 153
2. Numerical orFunctionalConstants 154
3. TheDifficulty ofExpressingNon-Dependences 159
4. Conclusion 161
CHAPTER 10/Rotationand Translation:simultaneity? 163
1. Introduction 163
2. TheInquiry: questionsandresults 165
3. Discussion and Suggestions 169
CHAPTER 11/From Electrostatics toElectrodynamics:
historical andpresentdifficulties 173
1. Incompleteness ofan Analysis CentredontheTerminals
ofthe Generator 174
2. History oftheConceptoftheElectricCircuit 175
3. TheReasoning ofStudents Today 180
4. Confusions between Charge andPotential 184
5. Conclusion 185
CHAPTER12/Superpositionof Electric Fields and Causality 191
1. Introduction 191
2. “Field Only ifMobility”? Questionnaires on insulators 195
3. CauseintheFormula:the Questionnaire 201
4. Summary andPedagogical Perspectives 206
viii Table of Contents
CONCLUSION 209
BIBLIOGRAPHY 215
SUBJECT INDEX 225
NAME INDEX 229
Acknowledgments
This work is the result of a long-term group effort, to which also
contributed, in our many discussions, Ahmed Fawaz and more recently,
Martine Méheut and Gérard Rebmann. My sincere thanks to them. The
support and interest of my Physics colleagues at the Université Denis
Diderothave alsoproved essential.
I am indebted to the pupils, students, teachers and university professors
withoutwhom the investigations on which this book is based would not have
beenpossible.
I am grateful to Michel Viennot whose careful and demanding study of
this book provided me with the views of a non-specialist with a good
knowledge ofscience.
The translation ofthis work was carried out under excellent conditions
thanks to the competence and kindness ofAmélieMoisy. And Robin Millar,
who read the English version over completely, has been of invaluable aid.
Mywarmestappreciationtothemboth.
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