Frequently-Asked Questions


What makes Six Ideas different from standard text?
Is Six Ideas effective in teaching physics?
How can I order the texts? How much do they cost?
What is different about the second edition?
How can I get a copy of the instructor's manual?
Don't the new chapter overviews discourage reading?
What if I must teach geometrical optics?
Is there a lab program associated with the course?
Why doesn't the book contain answers to at least some homework problems?

Can I post solutions online?
When will the 3rd Edition be available?
What is different about the Draft 3rd Edition of unit E?

What makes Six Ideas That Shaped Physics different from a standard text?

The answer to this question could be long! The short answer is that everything (the format, the style of presentation, the order and choice of topics, the types of explanations used, homework problems, and so on) has been rethought from the ground up and extensively tested over ten years to (1) more effectively help students to learn to think like physicists and to keep them excited about physics (2) support professors in offering an active and engaging classroom experience for students. Here is an abridged list of just some of the most important and unusual features of the text:


  • Unit-based, six volume structure
  • One chapter in the text corresponds to (at most) one class day
  • Much more contemporary physics than a standard text
  • Some classical physics topics are removed (to keep the pace low)
  • The presentation is highly focused (to keep the pace low)
  • Support for active learning and peer-instruction in class
  • Support for group learning in recitation sections
  • Natural links to active demonstrations
  • User-friendly notation and terminology
  • Explicit instruction in the art of model building and problem solving
  • Solution frameworks to help students organize problem solutions
  • Homework problems that challenge students to synthesize their knowledge
  • In-text exercises (with answers) to keep students reading actively
  • Chapter overviews at the beginning of each chapter help students stay oriented and review material
  • Extensive use of the results of physics education research

and so on! For a deeper discussion of the issues and differences, see Six Ideas Overview page or the Instructor's Manual.


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Is Six Ideas effective in teaching students physics?

An article by Richard Hake in the January 1998 issue of American Journal of Physics discusses the difference between traditional physics classes and what he calls "interactive engagement" classes in terms of student performance on a standardized test of newtonian mechanics called the Force Concept Inventory. By the measure that Hake uses, the average improvement on this test for students at Pomona was 0.63 during the fall of 2000 and in the 0.50 to 0.68 range during the past few years (the upper middle of the range for IE classes), compared to 0.230.04 for traditional instruction. Moreover, this test examines students' understanding of newtonian mechanics, a topic that we spend less time on than traditional classes normally do! We get similarly above-average results for the Brief Electricity and Magnetism Assessment test. For more information, see the Evidence of Success page.


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How can I order the texts? How much do they cost?

You can order the texts through the McGraw-Hill site or by contacting your local McGraw-Hill sales rep or through an online source such as Amazon. The price per volume is about $35. You can get economy pricing (about $140) on a set of all six texts.


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What is different about the second edition?

All volumes of the second edition share the following new pedagogical features:


  • Shorter chapters (less than 5300 words) make preparing for class less daunting
  • A more flexible problem-solving framework is used consistently throughout the text.
  • Formula boxes link important equations with the information needed to interpret and use them
  • Many more photographs enliven the presentation
  • Two-color, professionally-drawn line art helps make concepts clearer
  • The professional layout is more open and inviting
  • Many additional problems provide more flexibility for instructors
  • A new 2-page chapter overview replaces the old overview and summary pages
  • New unit maps based on a computer menu metaphor make it easier for students to locate a chapter in a unit's structure
  • A new centralized glossary (keyed to chapter sections) replaces the chapter glossaries
  • New and better supporting software is linked to the text in important places
  • The information on the inside front and back covers has been reorganized and made more complete
  • A number of errors have been corrected

In addition, the material in all the units has been thoroughly and carefully revised, mostly with an eye to making the material more accessible and improving the logical organization of topics. Here are some notes on changes in specific units.


  • Unit C: I have substantially reorganized the beginning chapters so that students get to the physics more quickly. The concept of force is introduced earlier and with more clarity. A different and more intuitive notation and terminology for impulse, work, and the analogous concept for angular momentum will make these concepts more accessible both to students and instructors. This unit also introduces the idea of an "interaction diagram" that is to a conservation problem what a free-body diagram is to a problem involving Newton's second law. Finally, the challenging material on angular momentum has been expanded to two chapters.
  • Unit N: This unit is shorter by one chapter (the missing material is now presented more efficiently in unit C). I have explicitly described the Newton computer modeling program in the text, and have provided exercises that allow students to explore the use of this program to examine realistic applications. I have also used this program to greatly reduce the mathematical complexity of the chapter on planetary orbits.
  • Unit R: I have included more material on using hyperbolas and hyperbola graph paper to construct multiple-observer spacetime diagrams and energy-momentum diagrams. A new computer program and other resources on the Six Ideas web site makes using hyperbola graph paper easier.
  • Unit E: This unit has been nearly completely rewritten to make it simpler and less mathematically daunting. It is now one chapter shorter. A comprehensive treatment of electrostatic potential now appears in chapter E3, and a supporting computer program helps students learn about equipotential diagrams. The material on magnetism has been tightened and simplified so that it is more conceptual and less mathematical. A new notation for the magnetic field allows one to get many of the benefits of the cgs unit system without the weird units. All important equations are now provided in standard form as well as a more elegant relativistic form. All discussion of Maxwell's equations and their implications is now based on Maxwell's equations in integral form, and an additional chapter in that part of the unit allows students to focus on learning about symmetry arguments and the definition of flux before digging into Gauss's and Ampere's Laws. Note: This edition is now superceded by the draft 3rd edition.
  • Unit Q: I have shortened this unit by one chapter (by combining some redundant material in the first few chapters) while adding some new material about complex numbers and the phenomenon of spin, and have presented a more careful discussion of the logic of quantum mechanics. This should provide a more solid background for discussing both the strange aspects of quantum mechanics and the simple and reasonably logical rules for the quantum mechanics model (and can even provide a basis for discussing hidden variables at the level of one of the articles that David Mermin has published in Physics Today, if an instructor desires). I have also greatly simplified the chapter on radioactivity, eliminating the "adjusted binding energy" concept and reducing the mathematical complexity. I have placed the chapters on the Schrodinger equation in a more logical position, and tied these chapters more explicitly to the new version of the Schrosolver computer program.
  • Unit T: I have made a discussion of the Boltzmann factor and its applications a more integral part of this unit. I have rewritten the StatMech computer program to be more flexible, and have provided a number of other computer programs that make the concepts of moving toward equilibrium and the effect of quantum mechanics on heat capacities more visual. Another program allows students to integrate the Maxwell-Boltzmann distribution numerically between any limits.

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How can I get a copy of the Instructor's Manual?


The first seven chapters of the Instructor's Manual are available online here. The remaining chapters provide problem answers and solutions, and (for obvious security reasons) are available only to professors using the text in their classes. If you are a professor, ontact your McGraw-Hill sales rep for a printed copy of the complete instructors manual and/or information about how to access the online instructor's materials.


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Don't the new 2-page chapter overviews encourage students to skip reading the actual chapters?

Apparently not. During the 2001-2002 academic year, students at Pomona College read units with the old-style summaries and units with the new 2-page overviews. I asked them to fill out an anonymous questionnaire about various features of the texts. While there was not universal agreement, the majority of students preferred the 2-page overview to the old-style summaries (some quite emphatically), particularly when the overviews were reasonably short (all of the final overviews are less than 860 words long). However, virtually no one reported (when directly asked) that they read the overviews instead of reading the chapter: a number in fact commented that reading the chapter was still essential to being able to do the homework.


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What can I do if I must teach geometrical optics?

I chose not to include geometrical optics in either of the editions of this text for two reasons: (1) I needed to remove something to make room for the contemporary physics topics, and (2) this material did not fit in any natural way into any of the units. Moreover, in my personal opinion, this material is less practical and important for the majority of 21st century students than it would have been for students in the first half of the 20th century. Still, many thoughtful professors disagree with me, and the topic still does appear on the MCATs, so one of the most-requested additions to Six Ideas is some material on geometrical optics (note that material on some aspects of physical optics does appear in unit Q).


At Pomona, we deal with this problem by offering a couple of labs on geometrical optics. This is because the evidence strongly suggests that students learn this particular material much better from doing hands-on experimental work than from classroom instruction. I have posted the materials for the labs we do on the intructor's web site.


However, for those who need classroom materials on geometrical optics, we have also posted a five-chapter "subunit" on geometrical optics graciously provided by Paul DeYoung of Hope College.


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Is there a lab program associated with the course?

Because every college and university I know has very different lab organizations, equipment, and goals I have not attempted to provide a general Six Ideas lab program. The instructor's manual discusses some things that I learned during the IUPP process, and explores one possible structure for a Six Ideas lab program. You can also download some sample lab materials describing labs we have created for the Six Ideas course at Pomona College.


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Why doesn't the book contain answers to at least some homework problems?

This question is most often asked by students, who would like to have answers available so that they could check their work and/or practice doing problems when reviewing for tests. I personally think that this request is reasonable, and I always give such answers to my classes before tests.


However, I have also found that some professors like to do things differently, for a variety of good reasons. So rather than force one particular approach down everyone's throat, I have elected to make short answers to homework problems available on the instructor's site. An instructor who so chooses can print out a set of answers and display it for his or her students or (preferably) make it accessible to students through the ProbViewer program. Students who would like to see such an answer sheet should request this from their instructor.


By the way, I strongly urge instructors to provide at least some answers whenever possible. I think that this can help make the course material more accessible to students.


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Can I post solutions online?


Yes, after a fashion. In August 2005, I set up a system for allowing students to view existing problem solutions online without requiring the instructor to post things on a website. In August 2007, I added a way for instructors to post their own solutions using the same mechanism. Please visit the instructor's web site for more information.


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When will the 3rd Edition be available?


The third edition is still in progress. I should have a firmer date after my sabbatical in the fall of 2007. However, a draft 3rd edition of Unit E is available (see below), and is strongly recommended.


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What is different about the draft 3rd edition of Unit E?


The draft 3rd edition of Unit E is available from McGraw-Hill Custom Publishing: the ISBN is 0-07-354099-4. (I also recently saw it available on Amazon). Even though I make no royalties from this draft, I strongly recommended upgrading to this edition. Its features include:


  • I have included a separate chapter on computing the fields of continuous charge distributions.
  • The two chapters on magnetic fields in the 2nd edition have been expanded to three.
  • The material on symmetry that had its own chapter in the 2nd edition has been absorbed into the extra chapters mentioned above. This gives students more time to get used to these hard topics.
  • I have streamlined and compressed the discussion of electric circuits into two chapters. (Students seem to find this material simpler than some other topics.)
  • The permittivity and permeability constants have a much higher profile in this edition.
  • I have returned to emphasizing the differential form of Maxwell's equations (as I did in the 1st edition). The differential form is much clearer conceptually and more useful for treating electromagnetic waves. However, students do not calculate fields using the differential form (other than for the simplest unidirectional cases).
  • Rather, a separate chapter explains how one can integrate the differential forms of Maxwell's equations to yield integral forms, and how to use these integral forms to calculate the static fields of symmetrical objects.
  • The "derivation" of the time-dependent terms in Maxwell's equations has been greatly simplified.
  • The use of relativity has been minimized and greatly simplified.

I have used this draft for two years now, and have found it to be the strongest version of Unit E yet. In the spring of 2007, I gave my students the Brief Electricity and Magnetism Assessment test, and my students earned an average post-test score of 58% (quite a bit better than typical traditional-instruction scores of 35% to 47%), even though my students only spent 5.3 weeks on E&M.


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