Klaus Lüders Robert O. Pohl Editors Pohl’s Introduction to Physics Volume 1: Mechanics, Acoustics and Thermodynamics With videos of 77 experiments Pohl’s Introduction to Physics Klaus Lüders Robert O. Pohl Editors Pohl’s Introduction to Physics Mechanics, Acoustics and Thermodynamics, Vol. 1 Editors Klaus Lüders Robert O. Pohl Fachbereich Physik Department of Physics Freie Universität Berlin Cornell University Berlin, Germany Ithaca, NY, USA Translated by Prof. William D. Brewer, PhD, Fachbereich Physik, Freie Universität Berlin, Berlin, Germany Additional material to this book can be downloaded from http://extra.springer.com. ISBN 978-3-319-40044-0 ISBN 978-3-319-40046-4 (eBook) DOI 10.1007/978-3-319-40046-4 Library of Congress Control Number: 2017944730 © Springer International Publishing Switzerland 2017 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, repro- duction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are be- lieved to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institu- tional affiliations. Printed on acid-free paper This Springer imprint is published by Springer Nature The registered company is Springer International Publishing AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland Preface to the Second English Edition The first English edition of Pohl’s “Physical Principles of Mechanics and Acoustics” appeared in 1932 (published by Blackie & Son, Ltd., London and Glasgow). It was based on the second edition of Pohl’s “Einführung in die Physik, Mechanik und Akustik” (Julius Springer, 1931). The present new, second English edition, based on the 21st edition of “Pohls Einführung in die Physik”, Vol. 1, (Mechanik, Akustik und Wärmelehre) (Springer Spektrum, 2017), has now been published after nearly 85 years! Following R.W. Pohl’s death in 1976 and the posthumous appearance of the 18th edition in 1983, since 2004 we have edited three new revised and updated editions, based mainly on the 16th edition (1964), the 13th edition (1955), and the 18th edition. The major change in this new series was the addition of 74 videos demonstrating many of the experiments that R.W. Pohl had developed and used. It is also augmented by comments in the margins when they appeared to be helpful as additional explanations or were needed to provide more modern information (see the Preface to the 19th edition). We have in addition included the collection of exercises which Pohl provided for the first English edition, and we have supplemented these (see the Preface to the 20th edition). The exercises were not included in any of the first 18 German editions. We have furthermore modified some mathematical formulations, symbols, and units so that they conform to the recommendations of the International System of Units (SI). We gratefully acknowledge the help of Professor W.D. Brewer of the Physics Department of the Free University of Berlin, not only for carrying out the translation of the text with great quality and speed, but also, and this is probably even more important, for his help with the identification and clarification of unclear parts in the text and in our comments. The English-language readers will appreciate the numerous links he added for further information. We also wish to thank Dr. T. Schneider and Ms. D. Mennecke-Buehler of the Springer-Verlag for making this edition possible, and for their generous help in carrying out its preparation and production. Berlin and Göttingen, March 2017 K. Lüders R. O. Pohl v Preface to the Twenty-First German Edition One of the most extensive changes in this new edition concerns its format, and is intended to make the books more readable. “Pohl” will now be published for the first time as an e-book, but also as a printed version with a new format. The numbering of the chapters, figures, equations etc. now conforms to the usual system in modern textbooks. The relevant exercises are given at the end of each chapter. We have also made major changes to the accompanying videos. In the e-book format, they are now more readily accessible and can be called up directly using the appropriate links in the text. All those videos which were produced in cooperation with the Institute for Scientific Films (IWF) in Göttingen are now available in their original quality and with a spoken text. The remaining videos were to some extent supplemented and in one case replaced by an improved version. Two new videos have been added: “Kepler Ellipses” (an excerpt from the opening show of the 2009 “High- lights der Physik” in Cologne), and “The Magdeburg Hemispheres” (an excerpt from a Lichtenberg Lecture given by Prof. G. Beuermann in Göttingen). At the same time, we have taken advantage of the opportunity to review all of the text critically. This has led to a number of clarifications, both in the text and in the figures, including the addition of several new figures, notably in Chapters 12 and 19. We owe special thanks to Prof. K. Samwer from the First Physics Institute of the University of Göttingen for his committed and helpful support of the preparation of this new edition in a variety of ways. We also wish to give particular thanks to Prof. G. Beuermann, J. Feist and C. Mahn from that Institute for their various and dedicated assistance. Furthermore, we wish especially to thank Dr. J. Kirstein from the Physics Didactics group at the Free University of Berlin for his professional and speedy editing of the videos. We are once again indebted to the Physics Department of the Free University and its administration for providing working facilities and for the helpful efforts of many of its members in solving technical problems, especially in connection with computer technology. Finally, we heartily thank the Springer-Verlag, and in particular Dr. V. Spillner, Ms. M. Maly and Ms. B. Saglio for their stimulating and agreeable cooperation. Berlin and Göttingen, July 2015 K. Lüders R. O. Pohl From the Preface to the 20th Edition (2008) The many positive comments from readers of the 19th edition of POHL’s Introduction to Mechanics, Acoustics and Thermodynamics have encouraged us to publish a new, revised edition. This also gave us the opportunity to include some supplementary material which we believe to be important. In addition to new or revised marginal comments and a few factual clarifications within the text, this new material consists in particular of additional videos and a set of exercises for the readers. Also, the sections on osmosis and diffusion from earlier editions have now been included here. This time, the videos were filmed under our own direction in the new lecture hall in Göttingen, in addition to several filmed in cooperation with the Physics Didactics group at the Free University in Berlin. In choosing the topics, we have again been guided on the one hand by our attempt to present ’lively’ illustrations of physics, and on the other by our intention to document typical demonstration experiments in the tradition of POHL, which in some cases are no longer being showneveninGöttingen. The major portion of the exercises originates with an earlier English-language edition (from 1932!); they are thus POHL’s original exercises. However, we found it desirable to add some more exercises which deal with questions that either relate directly to the videos or illustrations, or that complement the experiments, which are sometimes described rather briefly in the text due to lack of space. These exercises are thus not problem sets in the usual sense, but rather they are intended to help the reader achieve a better understanding of the sometimes difficult physical concepts described in this volume, and furthermore they provide additional information. vii From the Preface to the 19th Edition (2004) For over thirty years, from 1919 to 1952, R.W. POHL gave the introductory lectures in experi- mental physics at the University of Göttingen for students of a variety of major subjects. The three-volume set of textbooks based on those lectures pursued a double goal for many years: On the one hand, they were intended to arouse the readers’ interest in physics; and on the other, they served as textbooks for teaching basic physics to interested students. Even though in more re- cent decades, physics education at the university level has adjusted more and more to the needs of various professions and now includes many specialized courses, the goals of POHL’s works are still valid and topical. We are therefore convinced that these books still convey a fascination for the experimental investigation of physical phenomena and deserve a place on the bookshelves of modern-day students. That is the reason for the present new edition, initially covering the fields of mechanics, acoustics and thermodynamics. A second volume will present the most important topics from electrodynamics and optics.