Mary Jo Nye: The last speaker for this session is one of our own faculty members and we’re very glad that he agreed to join this conference. Ken Krane is professor emeritus within the physics department. It hardly seems emeritus because we see Ken all the time and he’s as busy as he’s ever been, although he’s not chairing the department anymore. We have the new chair of the physics department with us. Ken has been with Oregon State University since 1974. He obtained both his Master’s and his PhD in Physics from Purdue University. He received the Millikan Medal which recognizes teachers who have made contributions to the teaching of physics from the American Association of Physics Teachers in 2004. He has written a number of different correlation studies. He’s been very active in physics education on both the national and the local level. It’s a real pleasure to have Ken to talk with us about "Making Modern Physics Textbooks: The Collision for Physicists of Full-Time Commitments." [Applause] [0:29]

Kenneth Krane: I want you to notice that my talk is the smallest one. It’s only 289 kilobytes. Thank you Cliff and Mary Jo for the invitation to be part of this distinguished group. So my talk is titled "Making a Modern Physics Textbook." First of all, I want to acknowledge my debt to Linus Pauling. I learned quantum mechanics from Pauling’s book, which Dudley Herschbach is going to talk about tomorrow. This is a first edition, which I bought when I was a graduate student for the princely sum of $8.95 which, at that time, was a week’s worth of food for me. Despite the best efforts of my professor and the textbook, I nevertheless learned from that particular book. I want to talk about making a modern physics textbook and I am using ‘modern’ in two contexts. The designation ‘modern physics’ has come to have a significant meaning to physicists. It means anything other than classical physics; particularly, the theory of relativity which just celebrated its centennial a couple years ago, and quantum mechanics which is about 80 some years old. Hardly modern by any definition of the word but nevertheless for physicists it’s what passes under the title of modern physics. The second meaning is in terms of contemporary physics textbooks. I want to use both of those meanings. [2:13]

The clash of competing commitments. What are these commitments for the typical professor who might want to write a physics textbook? You all know what those are, right? There’s teaching. There’s research. There’s university administrative duties. There’s national committees and other professional society obligations, and maybe there’s even time for some family and personal life. In the midst of all that, how and why does textbook authoring manage to fit into this agenda? Let me tell you a little bit about my history of textbook writing. Mary Jo alluded to a couple of things but I’ve been at this for about thirty years now and I came into it quite by accident. I didn’t set out to be a textbook author. The first edition of my first book of Modern Physics was published in ‘82. I started working on it in ’77, so that’s thirty years ago. Introductory Nuclear Physics was published in ’86, the Resnick and Halliday collaboration in ’92. The Second edition of Modern Physics, the Fifth edition of Physics and the Third edition of Modern Physics should be out next year. As you can see, that’s about a four, five, or six year cycle. It’s been a continual process. There’s been no real breaks in the publishing life for me. [3:24]

Why do this? What’s wrong with physics textbooks and the courses that go with them? Well, first of all, the content is overloaded and that’s because textbooks are not written for students. They’re written for one’s colleagues. There’s a lot of material in textbooks that is really not intended for students. It’s only there because your colleagues expect it to be there. They don’t expect to actually use it in teaching but they expect to find it in the book. A lack of a coherent storyline. If you ask somebody who writes a new physics textbook what the point of the book is, what do they hope to do, they often have a tough time answering because there is no coherent storyline in most books. Insufficient attention to contemporary topics. Introductory textbooks in biology and chemistry are all about twentieth century biology and chemistry. Introductory textbooks in physics are all about 18th and 19th century physics. If you look at a typical introductory textbook in physics, most likely you will not find the word ‘atom’ in the entire book. What little contemporary material does find its way is often overly descriptive. It’s just an endless series of definitions: ‘This is a Type 1 Superconductor.’ ‘This is a Type 2 Superconductor.’ ‘Here’s the Meissner Effect.’ Right? Students really can’t relate to it and it’s clearly marked as optional. They draw boxes around it or they print it in different colored type. You might as well put a flashing neon sign in front of it and say "Do not read this because it will not be on the final exam!" Finally, in many books, there’s insufficient attention to student reasoning difficulties as revealed by physics education research. In the last twenty years or so, there’s been a flurry of activity in the field now called Physics Education Research, which is now done not in schools of education but in physics departments in the U.S. As a result, we know a great deal more than we did twenty or thirty years ago about the way students learn physics. I’ll say a little bit more about that as we go along today.

So why right a textbook? Well, you can certainly offer a fresh viewpoint. You can use a modern pedagogy and again incorporate these results of physics education research. You can project a less formal and more student friendly attitude, especially for students who will not be physicists. I didn’t know any textbook authors when I was an undergraduate taking physics. I had never seen a textbook author but I had this vision of what they must look like. They were very severe men, and all men of course, no women, wearing three piece, tweed suits, redolent of cigar or tobacco smoke, had goatees, wore a pince-nez or a monocle and spoke with a vaguely European accent - maybe German, maybe Hungarian - or something of that sort. They were certainly very severe, unfriendly men. One has the opportunity to introduce contemporary topics, applications and results of new experiments. This is the real challenge for me as a textbook author. It’s not to introduce contemporary physics in a superficial way but to go and read a paper in physical review letters and say "You know, I’d really like to be able to explain this in a way that a freshman student who’s majoring in Engineering, who’s not going to be a physicist, can appreciate this new experiment in particle wave duality or tests of general relativity in a way that I can not only explain it to the students but give them some questions and problems that they can take home and be analytical." That’s the real challenge. Finally, one has an opportunity - and I apologize, at a history conference I shouldn’t mention this - one can deviate from the traditional, often chronological, ordering of subjects. Sometimes the chronological order is not the pedagogically superior way of ordering. I will give you an example here. [7:01]

Opportunity to eliminate bad pedagogy. This figure shows up in a lot of physics books. It often mystifies me. What it purports to show is an allowed Bohr orbit and around this Bohr orbit is a de Broglie wave. This is often introduced in the context of the Bohr model. It has never been apparent at all to me what this is supposed to show. First of all, the Bohr orbit itself is of complete fiction, right? Around this Bohr orbit is something that is oscillating back and forth. You know an electron is not doing that. I would like my students to start to think of the de Broglie waves as eventually representing some sort of a probability amplitude. Is there something around here that has a large probability of being found here, and zero probability of being found over there? This is very mystifying. Of course, if you know the derivation of this, it comes out of the Bohr angular momentum quantization condition which is also dead wrong. Bohr got the right result for the wrong reason when he tried to quantize angular momentum, so this needs to be eliminated from textbooks. It is a very confusing drawing that students get nothing out of, but yet it persists. I claim responsibility for this bit of bad pedagogy. This is the standard first problem that we give students to solve in quantum mechanics. It’s the particle trapped in one dimension between two infinitely, impenetrable walls. It’s meant to demonstrate the fact that we have this quantization condition that emerges whenever we try a particle. Physicists look at this and every physicist understands what this diagram means and it’s a very compact diagram because we show the allowed energy levels and the probability distributions on the same diagram! We’ve combined two figures into one. As we discovered, when we started interviewing students, one-on-one, that were taking this course, we found that this created a lot of confusion for the students because they understood that somehow the vertical axis represents energy but then they are very confused about what these bumps represent and they tend to think of it as a roller-coaster sort of thing where something is moving very fast here and very slow up here. The idea is to change this drawing to make it more pedagogically acceptable to students and this is one way that we’ve come up with to do it. Instead of showing the probability densities as a vertical displacement, we show them as shadings on the energy level diagram. And now we are showing it as two separate diagrams in the next edition of the book to try to eliminate the confusion completely. [9:28]

Here’s an example of deviating from the chronological order. So this is the traditional order for introducing topics in early quantum mechanics: You have the Bohr model, then a decade later comes de Broglie waves, and then hard on the heels of that is quantum theory and atomic structure. It struck me when I was writing the first edition of Modern Physics about thirty years ago that this was not the right order to explain these topics in. I came up with a slightly revised order; de Broglie waves first, then the quantum theory, Schrödinger equation and so forth, and then you kind of back track and do the Bohr model and then come into atomic structure. It felt better to me, pedagogically. In the last twenty years, a couple of groups have done some education research and found that it is really the superior order because we know the Bohr model is wrong. In this particular ordering, I can tell students in my lectures about the Bohr model one day. At the end of that lecture, I spend the last ten minutes telling them why the Bohr model is wrong and the very next day we talk about the correct quantum theory of atomic structure. Whereas over here, you’ve got several weeks between the Bohr model and atomic structure and maybe you give them exam where they have to actually study the Bohr model in preparation of the exam. It becomes what the psychologists call ‘imprinted.’ The students really believe in the validity of the Bohr model. The chronological order is not always the best from the pedagogic point of view. [10:54]

Alright, so what has changed in the thirty years that I’ve been looking at textbook writing? First of all, the table of contents was the course syllabus thirty years ago, and today we view the table of contents as a kind of roadmap. People complain that physics textbooks are overloaded with material and you know, when you go to AAA and buy a roadmap you don’t complain that it is overloaded with roads. You know, it’s just a guide on how to get to point A and point B. You don’t necessarily have to follow all the roads on a roadmap. What is expected these days is to offer a lot of ancillary materials: an instructor’s manual that has solutions to all the problems in the book; a student study guide that has solutions to some of the problems in the book and questions to help direct the students to self study; a test bank; an online homework system is a feature of a lot of books now where you go on the web and you get homework problems and you submit the answers to the homework problems on the web and they are graded automatically; and of course a website with lots and lots of material on it. Writing a textbook sort of becomes an enterprise that involves a team of people these days. Certainly, as I mentioned, more contemporary topics and applications in a way that students can really relate to. The textbook is the sole resource versus the textbook is one component of a teaching strategy in a course. You see the course globally, not just focused around the textbook but where the student has access to a lot of different resources and instructors as well. You see a lot more illustrations in textbooks these days. Certainly a lot more use of color. College-level textbooks have begun to resemble high school textbooks in that regard. We know a lot more, as I mentioned, about student reasoning processes. A lot has changed in the demands of the textbook author in thirty years but I object when people start to talk about how we need to revise our textbook because students have weaker test preparation or shorter attention spans or poor reading comprehension. They spend too much time watching TV or looking at computers. There’s really no solid pedagogical evidence that this is true and even if it is true it doesn’t make any difference because we still have to deal with the student audience that we have and we can’t throw the burden of guilt on the high school teachers. We have to deal with the students who show up in our physics courses at the university. [13:08]

Alright, so what are the ideal attributes of a physics textbook? First of all, an abundance of work examples to help students develop problem solving skills. The old way of teaching was to watch me go to the blackboard and work problems, and you can learn to work problems by emulating an expert problem solver. Well, we know that doesn’t work. Students have to build their own learning environment and a lot of us believe in a kind of constructionist philosophy of education, so it helps to show students worked examples in the book that they can fight their way through, or they can see some of the alternative paths in the book or in some of the ancillary materials. Learning goals have to be clearly established and explained to students and the instructors: ‘as a result of studying this chapter you will be able to…’ and you have a list of things that students are supposed to get from that chapter. To develop the content in a coherent manner, again you have the story line. You have to look at everything that’s in the book and say "Why is that there? Does it relate to something that’s been done previously? Is it a precursor for something that I want to do later on?" If you can’t answer yes to either of those questions, you ought to look very seriously at whether you want to include that in the book or not. Greater variety of end of chapter problems. Again they are part of the learning aid for students. Graded ability levels. Incomplete or open-ended problems, where a student has to actually go to the web or guess at some quantities rather than giving them all the numbers they need to work the problem. A lot of material requires them to synthesize things from previous chapters. A lot of qualitative questions to help students develop conceptual reasoning skills. This is really important because, as the physics education research has helped us to discover, that conceptual understanding comes before problem solving ability. A lot of these things that I am telling you seem like tautologies but they were very hard lessons for the education community to learn. A lot of support for the instructor is necessary. We know instructors are busy, so we have to provide them with all these ancillary materials these days, problem solutions, group projects - because a lot of us believe in active engagement, that the passive lecture is not the best way for learning, that students have to be engaged - conceptual questions for class discussions, a lot of access to simulations and animations because students learn in different ways, and advice on selecting content to emphasize different story lines that can be developed within an existing textbook. You don’t just throw a physics textbook with 60 chapters at an instructor. Instead, you say "Here’s one pathway that you can take through these 60 chapters where you can eliminate these chapters if you choose not to emphasize that material." [15:39]

What do we know about physics education research? We know that teaching by telling is seldom effective. The "sage on the stage" mode of learning is not the most effective one. Even though that is how most of us learned, it’s not a really effective procedure for most of the students who are not going to go on and take many more physics courses. The best students at the best universities often display fundamental conceptual misunderstandings even post-instruction. This really kind of frightening but it's something we really have to learn to deal with. Students have to be active rather than passive participants in the learning experience. We have to guide them through developing the logical thought processes. We can’t just assign them problems to work outside of class and expect them to learn physics. Again, seems like a tautology, knowledge is organized differently by experts and novices. You can’t just say "watch what I do and learn to do it." You have to teach them with an idea of understanding how they’re organizing the knowledge that you’re giving them. You have to have some effective methods of formative assessment. This is, of course, an educational term but what it means is that I’m never satisfied unless I leave class each day without some understanding of what the students have gotten out of my lecture or the reading they’ve done in preparation for class. A lot of students learn visually, so we have to develop interesting visualization techniques and computers, of course, are wonderful for this. Finally, what is the effective use of technology? Just because the technology is there doesn’t mean that you have to use it with your course. The successful textbook author must buy into this national physics education research program which has been very well established. It’s robust. It’s replicable, clearly communicated learning objectives, guides to different pathways through the text, group activities, visualizations and so forth. [17:31]

Researchers as authors. Pauling wrote his books as an outgrowth of his research in chemistry and I was kind of curious to find out the extent to which authors of physics textbooks are embedded in research in physics. I took about a dozen or so of the best known introductory physics textbooks in the U.S. and looked up the author’s names in science citation indexes, looked at how many papers they published in recognized reference journals in the last 50 years or so. Halliday and Resnick are both retired, and I was a little bit surprised to find that a lot of the authors on these lists have published very, very little in the physics literature. It was rather surprising to me. These are introductory books, of course. But, nevertheless, there are relatively few active researchers who are also active in textbook writing. This is not the Pauling model of course. This is a very different kind of model, even at the introductory level. Gerald Walker, some of you may be familiar with, he used to write the Amateur Scientist column in the Scientific American and he was brought in to the Halliday and Resnick collaboration a few years ago. That collaboration fissioned actually into two books: an upper level book and a slightly lower level book. He’s the coauthor with Resnick and Halliday of the lower-level book. Ohanian is a publishing industry all to himself. Paul Tipler has also written a number of different books and brought in a coauthor recently. Serway has also written a number of introductory books. Randy Knight has a fairly new book out. Doug Giancoli has a number of textbooks out and Hugh Young took over a book which used to be called "Sears and Zemansky" which was kind of a standard text in the 1950s and 60s. For awhile that was "Sears, Zemansky and Young," Then Sears and Zemansky got dropped and Young took on Roger Friedman as a coauthor. Friedman is not even a tenured professor - he’s a lecturer at UC Santa Barbara. [20:04]

Look at the next level, the modern physics. The modern physics course is the one that comes after the introductory course. It’s normally taken at the end of the sophomore year by science and engineering students. We find that there are a few people who are still publishing widely. Steve Thornton is, like me, an experimental nuclear physicist, as was Chris Zafiratos. It’s kind of interesting that the three people with the largest number of publications on this list are all experimental nuclear physicists. I don’t know what that says about experimental nuclear physics or about textbook writing. Here’s Ohanian again, and again Tipler and Serway are on the list. There is a slightly higher level of research activity on this list. If you look at the next highest level, those would be junior/senior textbooks …anics, and classical mechanics you see again a slightly higher level of publishing activity. Here’s Ohanian on both lists again. David Griffiths from Reed College, Richard Lebouf from Cornell, Bob Sharer, who’s department head at Vanderbilt, just published a new quantum mechanics book. He’s an active researcher. Again, here’s Thornton. A slightly higher level of activity. I didn’t get a chance to look at graduate textbooks but I suspect if you look at that list you’d find an even higher level of publishing activity. But the model of Pauling, the person who has feet in both communities, is becoming exceedingly rare, especially at the introductory level. [23:02]

Okay, so what have I learned as an active researcher that has helped to make me a successful author? Again, a lot of these seem like tautologies but writing is informed by the literature of the field. Just like in research, you don’t try to become active in pedagogy without immersing yourself in the literature of the field. Attendance to topical conferences is essential to keep up with the latest developments. Again, I learn a lot and I steal a lot of ideas from colleagues at topical conferences. As a researcher, I have learned to go into the nuclear physics literature and accept the results of some papers and be very skeptical of the results of other papers. Of course, the same thing is true about papers and pedagogy, right? Not all results of physics education research are equally applicable to what I am doing or equally valid. New ideas can be tested and refined piecemeal through conference presentations, right? You know when you go to a research conference, you’re always giving brief talks about what you’re currently doing. You’ll get some criticisms or suggestions from people in the audience. The same thing is true about pedagogy. You don’t issue a new textbook spontaneously and suddenly, but rather you test bits and pieces of it out by bouncing it off of colleagues. Networking with these colleagues is quite essential. Testing and evaluation can be done using accepted research methodologies. You often see in the preface or introduction to the textbook, the author’s preface, that this material has been classroom tested. I’ve never really been sure what that means. It was used in manuscript form by the author and nobody ran screaming out of the classroom or something of that sort. [Laughter] [24:38]

So, what are the personal costs to the author? Time away from research is very significant. I have a hundred publications on my resume. I suspect if I had not been working actively publishing textbooks, that might be two hundred at this point in my career. There’s a great deal of time away from research, away from one’s graduate students. I’ve been very lucky to have good graduate students who have been able to survive even though they haven’t seen their major professor for long stretches of time. Time away from family. A very rigid publication schedule. It’s not like publishing an article. I mean, I have half a dozen manuscripts on my desk in various stages of completion for publication in research journals. But when you sign a contract to do a textbook, that manuscript has to be there at the date the contract specifies, because the publisher has purchased time at a printing house, has hired graphical artists, or others who are expecting to have this manuscript in hand to work on. They get very unhappy if they don’t have it on time. Expectation of revisions. It’s not like a research paper where you publish it and you’re done with it, right? There are subsequent printings. There are subsequent editions and the publisher expects you to be active in the preparation of those revisions. There’s a lot of communication with users. You get a lot of email once you publish a textbook that offers suggestions or criticisms and one is expected to respond to those people. There’s absolutely inadequate credit in the university merit system for writing a textbook. That’s true. I don’t know what one can do about that. Then, of course, for me at least, there’s been the challenge of remaining active and credible in both the research and the pedagogy communities. These are non-overlapping communities. They have different conferences each year. There are different individuals that are associated with both of those communities. There are benefits. There’s a great deal of intellectual satisfaction in writing a textbook and seeing it widely adopted, holding that book in your hand after it first comes out. There are, of course, the royalties. We haven’t built a swimming pool yet but it does put an occasional bottle of wine on the table and that’s certainly very satisfying. There are certain income tax benefits to having royalty income and I probably ought not to say too much more about that because these days you never know who’s listening. [laughter] I get a lot of national/international recognition. When I go to a conference, even if it’s a research conference, I’m always encountering graduate students or colleagues who used my books when they were undergraduates and they’re always happy to talk about it so, that’s really very pleasing. I have a lot of correspondence in my files from instructors who use the book and from students. Finally, there’s the pleasure at remaining active and credible in both the research and pedagogy communities. I count a lot of very strong friendships and associations in both those communities and I can’t imagine being at this stage in my career and having missed either of those two opportunities to interact with some very clever people. So, thank you very much. [Applause] [27:56]

Mary Jo Nye: We have some time for questions for Ken and then perhaps after that a little more discussion. Bob?

Bob: Yeah, I noticed in your talk you draw some conclusions from your successes and failures in your textbooks and one of the failures was fundamental conceptual misunderstandings in some of the best schools and in some of the best students. I was wondering if that is a fatal flaw or not, and if it is not a fatal flaw, why not?

Kenneth Krane: A flaw in the textbook?

Bob: In what the students have managed to learn.

Kenneth Krane: Let met tell you a brief story if I might. This comes from my colleague, Eric Mazur at Harvard, who sort of started me on the trajectory of my interest in pedagogy a number of years ago. In the story that Eric tells, he was teaching an introductory physics course at Harvard for premedical students. He and a colleague were teaching two different sections of the same course and they gave common final exams. This was the part of the course that deals with DC circuits. The colleague wanted to put a very complicated two loop circuit problem on the exam that involves quite a complicated algebraic problem. Eric wanted to put a very simple problem on the exam which was a circuit with some batteries and bulbs in it and ask what happens if you unscrew one of the bulbs if the bulbs become brighter or dimmer. The colleague argued violently against doing that because he said we’d never learn anything from such a problem. It turned out he was right. They didn’t learn anything from the problem. Not because everybody got it right but because almost everybody got it wrong. These are going to be cardiac surgeons. I mean, they need to know about things flowing around in circuits and things of that sort. They ended up putting both problems on and eighty percent of the students got the colleague’s complicated problem right but missed the very fundamental conceptual problem on the same topic. They could learn the algorithm for solving the problem but yet still demonstrated a very fundamental conceptual misunderstanding, post-instruction, at Harvard. It’s a little disconcerting. If it happens at Harvard, what hope is there for the rest of us? But that’s the story. [30:32]

Mary Jo Nye: Bassam?

Bassam Shakhashiri: What you were just talking about is common in chemistry also. I think it is somewhat presumptuous to say that because they took my course they are going to do better on everything that either I or someone else asks them. To me, it’s really the process that we engage our students and ourselves in that’s affecting their attitude more so than some specific piece of knowledge or helping them discard preconceived notions and misconceptions. That’s my comment about this. But I have a question for you. Fifty or sixty years ago, when book publishers contracted the authors, did they subject the authors to a three year cycle where you really have to upgrade and get a new edition and what affect does that have? Is that a change, according to the things you were talking about?

Kenneth Krane: Yes, it is, but not for me. My Modern Physics book is going into its third edition after 26 years. I think I would be dead and buried by now if I were on a four year publication cycle. I don’t think I could do it. Yet they do expect it because, of course, publishers get no royalties from the used book market. They would like to have new editions out every few years. I can’t keep up with that pace. [32:09]

Mary Jo Nye: There was a question back there.

Audience Member: Yes, first of all, you might notice the hat I’m wearing it says "What?" and also the shirt I’m wearing which is an interesting story. I’m a retired physics and chemistry teacher from [Clebo] high school and my son is teaching physics at [indiscernible name] high school right now. I have two ideas I want to throw out here: Why don’t we, in Oregon, take every university and every public school district and pool that money together and have a new show on OPB called "Oregon Education" which would start to educate Oregonians about the need for education and it’s two facts. The second one is, let’s start another class called "Career Exploration" in our high schools where we can take our kids and go and visit. How many kids are in here from high school? None right now. My daughter just came back here from Ethiopia. She graduated from Lewis and Clark. I talked to her last night and she said… [34:36]

Mary Jo Nye: Ken, do you have an answer? [Laughs] [Audience laughter]

Kenneth Krane: Sorry.

Audience Member: We got how many people in this room? Is this being video-taped?

Mary Jo Nye: Yes. [34:44]

Audience Member: I can go through of a hundred examples on this campus. Dr. Allan [Weltz?] He is one of our nation's top cancer researchers. He was here for ten days and his topic was […] I’m very interested in the University of Pittsburgh because my wife’s niece is the only person on the planet to have a double lung transplant, a full bowel transplant […] She’s also a teacher and is 40 years old […]

Mary Jo Nye: Finish it off.

Audience Member: I will finish it off in a moment but I am really pumped. There’s two facts that make me really angry. We are ranked 46th in the nation for support of higher ed. and we are also spending more money on 13,400 inmates than on 438,000 higher education students statewide. That’s a failure.

Mary Jo Nye: Thank you.

Audience Member: I’ll be quiet now. [35:33]

Mary Jo Nye: Next question.

Audience Member: You mentioned that overloading a textbook is one of the problems and you also mentioned that putting in newer examples is something that needs to be done. If you have too many new examples, the textbook becomes overloaded. Where do you draw the line?

Kenneth Krane: My philosophy is that I would like each new addition to be no larger than the previous one. Every time something goes in, something else has to go out. It’s incredibly difficult. I remember sweating blood over every word. When I wrote the proposal for the first collaboration with Resnick and Halliday, I had looked at what can we leave out. I sent the publisher a list of topics that I would propose to leave out in the next edition. Of course, publishers don’t make these decisions on their own. They circulate any proposal to a large number of reviewers. I remember getting a letter back from a very irate reviewer because I had proposed to leave out mutual inductance and this particular reviewer felt that mutual inductance was the centerpiece of any physics course and would never consider adopting a textbook that didn’t include mutual inductance. You’re not going to satisfy everybody. You’re going to have to make some very hard decisions but the idea is to prevent the textbooks from getting any larger. Any time something new goes in, something else has to be either shrunk down or eliminated. [37:05]

Mary Jo Nye: A couple more questions. Larry?

Larry: Does the publisher look at the national scene or the big state purchases, purchasers like Texas and California? Physics may not be as controversial a topic as some social sciences, but do you find that there’s any kind of political oversight?

Kenneth Krane: No. Certainly not at the college level. There might be at the high school level. There are no state-wide adoptions of college level textbooks. They are all individual campus adoptions. I don’t think that issue ever comes up. [37:41]

Mary Jo Nye: We have one more question for Ken and then we can open up for a just few minutes to the other speakers as well. Yeah?

Audience Member: I’ve been more interested in chemistry introductory texts and I have written a number of papers criticizing them. I have one thing I’ve wondered if it is common in physics. In almost all introductory chemistry texts, there are multiple errors of fact and also a number of concepts taught in detail which were obsolete a century ago. My question to you is: A; does this happen in physics and B; is there any mechanism you know of for correcting about it?

Kenneth Krane: Yes, to the first question and no to the second one. [Audience laughs]. Yeah, certainly it happens in physics. We include a lot of obsolete presentations even in our introductory textbooks. For instance: thermodynamics. It is something we have in common with chemistry. Most physics textbooks often offer a very, very classical approach to thermodynamics' second law, heat engines, refrigerators and that sort of thing. Modern contemporary physicists view thermodynamics very differently. They view it as very closely coupled with quantum mechanics. Entropy is a kind of side light in most presentations and introductory physics whereas it is very central to more rigorous presentations of thermodynamics. We’re wedded to this look at refrigerators and heat engines and that sort of thing. It’s a very engineering-based approach. none of which a physicist would use. On the other hand, we don’t even talk at all about astrophysics or the fundamental properties of matter at the introductory level. In terms of fundamental errors of presentation, most of these textbooks have been through so many editions and they’re so carefully vetted by reviewers that there’s not much of an opportunity for really fundamental errors, but small ones do persist. I’ve made my share of those and I can tell you that they do not only sneak in but they persist. [39:58]

Mary Jo Nye: All right. One or two more questions either for Ken or for another speaker. Dudley, did you have something?

Audience Member: I wanted to ask Krane a about his notion of a storyline because I don't quite understand it. Please correct me; I would think that a historical storyline is best to refresh their memory of how developed. You seem to suggest that there is another kind of storyline and I’m not quite clear what the other, better one might be.

Kenneth Krane: I can give an example from Modern Physics. In the standard modern physics textbook, about the first third is very historical. It’s the photoelectric effect and black-body radiation - the kind of classical experiments that led up to the quantum theory. The middle third is quantum theory. It involves the basic Schrödinger equation and applications to some simple systems which is very mathematically intensive. The last third is very descriptive. It’s about nuclear physics and particle physics and molecular physics and so forth - solid-state physics with almost no equations. The storyline gets lost. Where is the wave mechanics as applied to nuclear structure? Where is the notion of discrete energy levels as applied to particle physics? The idea is to make the textbook coherent by integrating that same storyline that you’ve used in the first two thirds of the book in the last third. Not to try to teach all about nuclear physics in one chapter, but to try to give students the idea that basic wave mechanics influences how we think about nuclear physics or particle physics. That’s what I mean by storyline. [42:01]

Mary Jo Nye: Dudley, did you have a question?

Dudley Herschbach: Yes. There is one syndrome I’m sure you’ve figured out how to avoid but I see it very prevalent in chemistry textbooks and some physics textbooks. In the back of the book, there are answers to say, even numbered problems and in each chapter there’s even and odd numbered problems that are sort of paired, clones or twins, so the students quickly learn that, since the professor is supposed to assign the odd numbered problems, they look in the back for the twin even numbered problem and see the answer, juggle the numbers there until they get that answer. Then if they juggle the parallel numbers in the assigned problem they are guaranteed to get the right answer and that’s the only principle they know, or need to know! [Laughter] Those Harvard students had learned that in high school, perhaps, I don’t know. I always think that’s quite delightful and so, of course, I don’t assign any problems. I used to teach freshman chemistry and I had to use the textbook. I tried to give them problems they can’t find any equations for in the book. That’s what I call subversive problems, because I think they’re the only ones that do any good. I wonder if you’re forced to do this "even numbered answers in the back" thing.

Kenneth Krane: Not really. I like to think of dividing that end of chapter material into exercises and problems and some of those exercises are useful. They need to get some practice at mashing numbers into equations even though they know what the results are going to be. They need to get some practice with units and dimensions and things of that sort. But, there need to be some intellectually stimulating problems where they can’t just look back at the appropriate section of the book and find the formula and plug the numbers in and get the answer. That’s the kind of problems that I think you are talking about but yet need to be intellectually stimulating. No, I agree completely. I think there needs to be both problems and exercises. [44:06]

Mary Jo Nye: Well, I think it is about time to conclude this session. I thank Ken and our other speakers. Thank all of you for coming. [44:13]