Understanding Physics

875 Pages·2002·45.889 MB·English

by  David C. Cassidy, Gerald Holton, F. James Rutherford

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UNDERSTANDING PHYSICS
Series Editors
John P. Ertel
Robert C. Hilborn
David Peak
Thomas Rossing
Cindy Schwarz
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UNDERGRADUATE TEXTS IN CONTEMPORARY PHYSICS
Cassidy, Holton, and Rutherford, Understanding Physics
Enns and McGuire, Computer Algebra Recipes: AGourmet’s Guide to the
Mathematical Models of Science
Hassani, Mathematical Methods: For Students of Physics and Related Fields
Holbrow, Lloyd, and Amato, Modern Introductory Physics
Roe, Probability and Statistics in Experimental Physics, Second Edition
Rossing and Chiaverina, Light Science: Physics and the Visual Arts
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UNDERSTANDING
PHYSICS
David Cassidy
Gerald Holton
James Rutherford
With 571 Illustrations, with 6 in Full Color
123
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David Cassidy Gerald Holton
Professor of Natural Science Mallinckrodt Professor of Physics and History
Natural Science Program of Science, Emeritus
Hofstra University 358 Jefferson Physical Laboratory
Hempstead, NY 11549 Harvard University
USA Cambridge, MA 02138
[e-mail] USA
James Rutherford
Education Advisor
American Association for Advancement
of Science
Washington, DC 20005
USA
Series Editors
John P. Ertel Robert C. Hilborn Cindy Schwarz
Department of Physics Department of Physics Department of Physics and
United States Naval Academy Amherst College Astronomy
572 Holloway Road Amherst, MA 01002 Vassar College
Annapolis, MD 21402-5026 USA Poughkeepsie, NY 12601
USA [e-mail] USA
[e-mail] [e-mail]
David Peak Thomas Rossing
Department of Physics Department of Physics
Utah State University Northern Illinois University
Logan, UT 84322 De Kalb, IL 60115
USA USA
[e-mail] [e-mail]
Library of Congress Cataloging-in-Publication Data
Cassidy, David C., 1945–
Understanding physics / David Cassidy,Gerald Holton, F. James Rutherford.
p. cm. — (Undergraduate texts in contemporary physics)
Rev. ed. of: The project physics course. 1971.
Includes bibliographical references and index.
ISBN 0-387-98756-8 (pbk. : acid-free paper)
1. Physics. I. Holton, Gerald James. II. Rutherford, F. James (Floyd James), 1924–
III. Harvard Project Physics. Project physics course. IV. Title. V. Series.
QC23.2 .C37 2002
530—dc21 2002020937
ISBN 0-387-98756-8 Printed on acid-free paper.
© 2002 Springer-Verlag New York, Inc.
All rights reserved. This work may not be translated or copied in whole or in part without the written
permission of the publisher (Springer-Verlag New York, Inc., 175 Fifth Avenue, New York, NY 10010,
USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with
any form of information storage and retrieval, electronic adaptation, computer software, or by similar
or dissimilar methodology now known or hereafter developed is forbidden.
The use in this publication of trade names, trademarks, service marks, and similar terms, even if they
are not identified as such, is not to be taken as an expression of opinion as to whether or not they are
subject to proprietary rights.
Printed in the United States of America.
9 8 7 6 5 4 3 2 1 SPIN 15110102
Springer-Verlag New York Berlin Heidelberg
A member of BertelsmannSpringer Science(cid:2)Business Media GmbH
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To the students and instructors whose advice, while using
the draft versions of the text and guides, helped to improve our work greatly;
and to Joan Laws, whose quiet expertise all these years
helped to bring the project to success.
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Science is an adventure of the whole human race to learn to live in and perhaps
to love the universe in which they are. To be a part of it is to understand, to un-
derstand oneself, to begin to feel that there is a capacity within man far beyond
what he felt he had, of an infinite extension of human possibilities. . . .
I propose that science be taught at whatever level, from the lowest to the high-
est, in the humanistic way. It should be taught with a certain historical under-
standing, with a certain philosophical understanding, with a social understanding
and a human understanding in the sense of the biography, the nature of the peo-
ple who made this construction, the triumphs, the trials, the tribulations.
—I.I. Rabi, Nobel Laureate in Physics
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Preface
Understanding Physics is a completely revised, updated, and expanded edi-
tion of the Project Physics Course. It is an integrated introductory physics
course, developed with funding from the Carnegie Corporation and the
Sloan Foundation and with the close cooperation of Springer-Verlag
New York.
In approach and content, Understanding Physics follows the trail blazed
by the earlier versions, but it includes more recent developments in physics
and a stronger emphasis on the relationships among physics, technology,
and society. We have sought especially to incorporate the salient lessons of
recent physics education research and practical experience gained in the
classroom.
The Audience
Understanding Physics is written primarily for undergraduate college stu-
dents not intending (at least initially) to enter careers in science or engi-
neering. These may include liberal-arts students, business majors, prelegal,
and prospective architecture students. We have found that when the course
is taken with laboratory work, it has been deemed suitable by medical
schools for premedical students.
An important group that this course is intended to serve are persons who
plan to teach, or are already teaching, in K–12 classrooms. As has been
widely discussed, there is a special need for improvement in the science
education of current and future teachers as an important step toward achiev-
ing greater scientific literacy in general. Many states have recently incor-
porated the contextual approach used in Understanding Physicsinto state sci-
ence education criteria. It is in part to meet the challenges of teacher
education that this course was developed as a resource, along with the usual
pedagogical training.
Since college students in introductory science courses usually represent
a wide spectrum of expertise in science and mathematics, this book assumes
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PREFACE
no prerequisites in science or mathematics beyond high-school algebra,
geometry, and general science. In this text we have taken great care to de-
rive all necessary equations very patiently, but whenever possible we have
used narrative text instead of equations to convey the meanings of laws and
concepts. Even if students have taken physics in high school, they often
still lack proficiency in even the most basic concepts and techniques. One
of the aims of this course is to enable all students to gain experience and
confidence with physical-science concepts and quantitative methods, and
with an understanding of the nature of science itself. Of course, for classes
in which the students are sufficiently prepared, instructors may decide to
place more emphasis on quantitative or other aspects of physics as appro-
priate. The course is designed with such flexibility in mind.
The Approach
A unique feature of this text, like its predecessor, is that it places the fun-
damental concepts of physics within the broader humanistic and historical
contexts in which they arose, but without handicapping students in tests
that compare their performance with students who have taken a less broadly
conceived, conventional physics course. Research has shown that students
exposed to our approach gain a much deeper understanding of both the
content and the processes of scientific research, as well as an appreciation
not only of what we know, but also of how and why we think we know it.
This approach has been endorsed by several national organizations, in-
cluding the National Science Foundation, the Research Council of the
National Academy of Sciences, and Project 2061 of the American Associ-
ation for the Advancement of Science. The National Research Council
stated in its National Science Education Standards:*
In learning science, students need to understand that science re-
flects its history and is an ongoing, changing enterprise. The stan-
dards for the history and nature of science recommend the use of
history in school science programs to clarify different aspects of sci-
entific inquiry, the human aspects of science, and the role that sci-
ence has played in the development of various cultures.
Thus, Understanding Physics operates on two levels, providing both the
fundamental concepts of physics and the humanistic and intellectual con-
texts in which the concepts developed. In addition to the necessary con-
cepts and equations, intentionally developed patiently, and using easy-to-
visualize examples, it aims to convey a real sense of the nature of scientific
*Washington, DC: National Academy Press, 1996; p. 107.