ATOMS IN MOTION Windows Version 1.0 Scott Johnson University of California, Davis ATOMS IN MOTION is published by Physics Academic Software. The software package includes a User's Manual. INSTALLATION To install ATOMS IN MOTION onto your hard disk, make sure that Windows is running on your computer and that no other programs are running. 1. Insert ATOMS IN MOTION diskette into your disk drive. 2. Use the Start menu to select Run. 3. In the Run dialog box, type A:\SETUP and click the OK button. This launches the setup program. 4. Follow the instructions on the screen for inserting the rest of the diskettes. STARTING THE PROGRAM To start the program 1. Select the Start button (usually in the bottom left hand corner of the screen). 2. Move the mouse upward to PROGRAMS. A second menu appears to the right. Choose the ATOMS IN MOTION menu. 3. Select the ATOMS IN MOTION program. OVERVIEW ATOMS IN MOTION is an interactive computer simulation of a solid, liquid, or gas modeled as a collection of spheres in a box. A real-time 3-dimensional animation of the atoms is continuously displayed along with a speed histogram and several calculated quantities to show the effects of changing various simulation parameters. You can use this program for lecture demonstrations or for student laboratory exercises at many different levels from high school through upper division undergraduate courses. At an introductory level, ATOMS IN MOTION provides a moving picture of how a gas, liquid or solid "looks", how pressure pushes on a piston, or how a solid melts. At a more intermediate level, it demonstrates heat capacity, free path length, Brownian motion, the equal distribution of energy, or many other concepts. It shows that thermodynamic laws are a direct consequence of large numbers of particles interacting in familiar ways, like pushing, pulling, and colliding. The simulated substance consists of up to four types of atoms in a cubic box. You can control many of the parameters of the simulation including the number, diameter, mass, color, charge, and bond strength of each type of atom, the position and velocity of each atom in 3 dimensions, the size and temperature of the box, and external pressure from a piston. The program calculates and displays the positions of the atoms, the speed histogram, and many thermodynamic quantities like temperature, pressure, volume, and internal energies. This software has been designed to be easy to learn to use. Only a few standard user interface techniques are required. Students can learn to use ATOMS IN MOTION in a few minutes, so even a single laboratory session has enough time for several exercises. In this manual, BEFORE YOU BEGIN deals with preliminaries like the contents of the package, system requirements, and installation of the program, ABOUT THE PROGRAM contains a tutorial and detailed descriptions of the various parts of the program, and STUDENT EXERCISES gives many suggestions for activities that can be done with the program. It gives me great pleasure to thank the people who have contributed to this project, which has now taken well over a full time year of my life. Wendell Potter at the University of California at Davis has guided the project for the past 8 years toward what students most need to learn and has used the program extensively in his introductory physics class. Mike Joyce helped me learn how to program in C++ and Windows and has been a source of endless encouragement through many long programming sessions. Bobby Lau has adopted the Macintosh version of the program and has rewritten it to be more "Mac-like," and in the process has improved both versions greatly. Allen Tucker at San Jose State University has allowed me to field test the program in his classes and has provided many valuable suggestions. My thesis advisor Larry Coleman has been very patient when my thesis research has taken a back seat to this program, sometimes for months at a time. Finally, my wife Karen (who is a professional computer programmer) has continually reviewed every revision of both the program and the manual and has been extremely supportive of this most non-lucrative endeavor. If, in some cataclysm, all of scientific knowledge were to be destroyed, and only one sentence passed on to the next generations of creatures, what statement would contain the most information in the fewest words? I believe it is the atomic hypothesis (or the atomic fact, or whatever you wish to call it) that all things are made of atoms-little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another. In that one sentence, you will see, there is an enormous amount of information about the world, if just a little imagination and thinking are applied. Richard Feynman From the first chapter, Atoms in Motion, of The Feynman Lectures on Physics COMPUTER SYSTEM Windows version ATOMS IN MOTION requires a Pentium-class processor running Windows 95 or higher, and 32 MBs of memory. The program and its example files will use about 1 MB of hard disk space. See the section Making the Program Run Faster for suggestions on how to improve the program's performance, especially on older computers. Macintosh version ATOMS IN MOTION requires a Macintosh with a PPC processor running MacOS 8.1 or higher (or 7.6 to 8.0 with the Appearance Manager), and 3 MBs of memory available to the program. The program and its example files will use about 1 MB of hard disk space. COPYRIGHT AND COPY POLICY Copyright 2001 by Physics Academic Software Publishing Organization All rights reserved Copyright 2001 by Scott Johnson All rights reserved Published in the United States of America ISBN 1-928550-16-9 Windows version ISBN 1-928550-17-7 Macintosh version Under the copyright laws, neither this software nor the documentation may be copied, in whole or in part, without the written consent of the American Institute of Physics, except in the normal use of the software or to make an archival copy of the software. The label provided with the package must be affixed to the archival copy. You may not give or sell unauthorized copies to anyone, but your license and all of the material purchased (with all archival copies and authorized copies) may be sold, given, or loaned to another person. ORDERING To order additional copies of the software package or multiple-copy licenses, telephone (800) 955-8275 or (919) 515-7447, send a fax to (919) 515-2682, e-mail pas@ncsu.edu, browse our web site at http://www.aip.org/pas/ or write to Physics Academic Software Box 8202 North Carolina State University Raleigh, NC 27695-8202 PHYSICS ACADEMIC SOFTWARE Physics Academic Software publishes physics educational software in cooperation with the American Institute of Physics, the American Physical Society, and the American Association of Physics Teachers. The editorial offices are located at North Carolina State University. Editor: John S. Risley Associate Editor: Margaret H. Gjertsen Managing Editor: MaryBeth Branigan Technical Editor: Julien C. Sprott Technical Copy Editor: Robert W. Brehme Editorial Assistant: Ashlyn B. Goode Proofreader: Elizabeth R. Harder Indexer: Barbara De Gennaro Cover Design: Hopkins Design Group EDITORIAL BOARD Robert J. Beichner, North Carolina State University Denis Donnelly, Siena College Robert Ehrlich, George Mason University Robert Fairchild, Nebraska Wesleyan University Robert G. Fuller, University of Nebraska John Gastineau, Morgantown, WV Graham Oberem, California State University at San Marcos E. F. Redish, University of Maryland J. C. Sprott, University of Wisconsin-Madison Edwin Taylor, Massachusetts Institute of Technology Jack M. Wilson, Rensselaer Polytechnic Institute Dean Zollman, Kansas State University Physics Academic Software reviews, selects, and publishes high-quality software suitable for use in undergraduate or graduate training in physics. Submitted software is peer-reviewed for excellence in pedagogical or research value. Physics Academic Software invites authors of software for teaching, laboratory, or research activities in physics to submit their software packages to the editor for review. Prospective authors should contact the editor at the address below for advice, stylistic conventions, and submission package requirements. Prof. John S. Risley, Editor Physics Academic Software Department of Physics North Carolina State University Raleigh, NC 27695-8202