Instructors

This textbook is probably nothing like the textbook you used to learn physics, assuming that you (like me) used e.g. Tipler, Halliday and Resnick, Halliday, Resnick and Walker, Fishbane, or any of the other physics texts typically used in the past in intro courses designed for physics majors. I'm hoping that it is like a breath of fresh air to most of you, if you (like me) have gotten increasingly irritated as physics texts have become ever larger, more cumbersome, more expensive to the student, more fragmented with inserted examples and little mini-blurbs until they all look like a web-page in which every link has been expanded inline so that the result is no longer readable.

One of my own pet peeves for some time has been textbooks arranged with too many chapters to cover at a chapter a week pace through a typical semester. I mean, what's up with that?

Now, a semester (at least at Duke) typically has approximately sixteen weeks total (late August through early December, or early January through the end of April). Some of these weeks are fragmented by things like a break or an important holiday. Other weeks are broken up by an in-class examination. The first week and the last week are normally less than completely usable as things start up and wind down. Practically speaking there are at most fourteen usable weeks in which one can teach physics, and only twelve of them can be used without interruption or distraction.

A very natural pace to teach with is to cover one chapter of physics a week. After all, with thirty or more information-dense pages per chapter, and over a hundred homework problems at the end of a chapter, it seems difficult to imagine a student being able to properly cover more, but most current texts have close to twenty chapters that would need to be covered in a typical semester if a student were not going to be forced to take three semesters of physics to get an introduction and move on in their chosen major or profession. This means that students, and instructors, typically have to cover two chapters per week at least four to six times per semester.

Instructors hate this (at least, I do). Students hate this. Inevitably things get omitted, or taught differently between sections as one professor chooses to compress thermodynamics while another chooses to omit statics, or sound waves. Students do poorly on compressed chapters taught two or more to a week as they struggle to extract key points from two or three times as much dross with little guidance in the text as to what is ``important'' (everything is important, right?). It creates battles over the curriculum, poor student reviews of the classes and textbooks, poor grades for otherwise bright students, and is just a waste all around.

This textbook is specifically designed to be taught at a pace of at most one chapter per week. In fact, it is assumed that several of the longer and more important chapters will be taught over more than one week. It leaves it up to the instructor to enrich the course with discussions, further examples, and a well-designed recitation and lab (although specific suggestions on how to do so are presented below). It leaves it up to the instructor and the department to set the pace, and to select curricular material to be omitted if desired. It leaves it up to the instructor to select problems from the relatively few provided to assign as homework, where the instructor can have the confidence that all the problems are primarily algebraic and range in difficulty from intermediate to quite challenging indeed. The textbook is specifically designed to be easy for a student to use and to be complete and well-organized enough that a student literally shouldn't need to take in-lecture notes on primary material.

This is a key point. It enables lecturers to consider using lecture differently, as a vehicle for conveying conceptual understanding and illumination, rather than as a venue for presenting all the stuff the book does poorly or omits altogether so that students have an even chance of being able to work the homework problems. The book should support self-learning on the part of the student, so that the instructor becomes a guide helping them along an arduous mountain trail where they do the work rather than a tour bus operator that points to the sights out of a window while they snooze. Metaphorically speaking, of course.

Now here is some advice for how best to design and teach a course using this text. Take it or leave it as you wish - I do not presume to judge any particular teaching style as good or bad as I think that this is highly individualized and I've known great teachers who use completely different approaches and yet succeed. The advice below does exploit some of the recent research on how best to teach physics, though, as indicated.

• I recommend assigning around ten problems per chapter/week of homework, although the text will ``work'' for assignments as minimal as just the starred problems plus one or two or as maximal as all the chapter problems. Note that these problems are mostly challenging and students will almost certainly need support to get through the more difficult ones.

• I recommend making homework an important component of the student grade (so that they take it seriously), but I also recommend arranging recitation so that any student that really tries can always complete the homework, however difficult, and get a homework grade in the mid to high 90's. The key here is to given them a really difficult assignment - one that is too difficult to do by the usual ``look up an equation in the text and plug it in'' methodology used by students, one they simply cannot do without actually using and hopefully learning the essential concepts and methodology - and then create an environment where (often to their surprise and great pride) they succeed in doing it anyway.

• After assigning really difficult problems for homework, back off on the exams and quizzes to a ``normal'' level - whatever you were using before. If you can get them through the difficult homework, I think you'll be amazed at the results. If their homework is more difficult than their examination problems, and you get them through them, they'll find the exam problems easy. If their homework is less difficult than the exam problems, or even just as hard, they'll find the exams difficult. This simply exploits the same principle used by every athlete in the world - if you work out regularly with 1000 Newton weights, 500 Newton weights seem rather light. If you work out with 250 Newton weights, 500 Newton weights seem impossibly heavy. View yourself as the students' personal trainer, there to encourage them and help them get those 1000 Newton weights up over their heads, if only for a few reps.

• Push the ``method of three passes'' (described below). This particular methodology is supported by all sorts of data on how the brain learns most effectively - the use of repetition, a resolution phase where conflicts are unconsciously resolved, a period of sleep to enable the formation of long term memory - simply increasing chair time helps, but this increases it a lot more painlessly and effectively than perpetuating the behavior of working on the homework some minimal amount of time the night before it is due (a typical student study pattern). If they use this method before recitation, review all problems in recitation, write up all the problems after recitation to hand it, and review the problems again before exams, they've seen the assigned problems as many as six or seven times, compared to the one to three that is typical of other patterns of study. ``Reps'' matter when forming memory, and forming memory is key to building a deep understanding!

• To support the students in doing the more difficult problems and encourage them to perform those repetitions, an effective recitation process is strongly recommended. Studies (and our own experience learning) show that students learn more physics working in small groups. Students learn more teaching each other than they learn being ``taught'' by a faculty person (so that the best way to teach is not to teach, a very Zen sort of concept). Students learn more solving a relatively few but very difficult problems than they learn from doing any number of ``exercises'' that involve trivial substitution of numbers into equations they are led to think of as ``important'' and hence try memorize, at least until they hit the fourth week of the course and the number of such equations starts to get out of hand. Memory formation should be incidental to working the problems, not a matter of memorizing abstract relations, to build deep understanding.

• Push the students to complete at least 2/3 of their homework before the recitation in which you go over the homework. If the assignment is (properly) difficult, most students will not have been able to finish even if they are e.g. future physics majors. On a really good assignment, your graduate TA will be knocking on your door sometime before recitation for ``help doing problem 12''. This is fine. As long as the students (including your TA) have struggled to finish, though, and tried each problem to the point of frustration on at least three separate days and times already, they are ``ready'' to be guided to completion in recitation either by their group peers or by you, the instructor.

• Devote at least part of every recitation to helping students through those last few problems they couldn't do. This is an excellent opportunity for Socratic teaching, rather than demonstration. That is, rather than showing students how to solve a problem, ask them questions or point to the ``key'' places they are proceeding incorrectly so that they have a chance to ``discover'' the correct solution themselves. When they have really worked on the problem beforehand, they sometimes ``get'' the solution all of a sudden in the groups or if you (as personal trainer) do nothing but draw a picture for them to get them started. This sort of ``light bulb'' experience is a great feeling and students start to enjoy experiencing it if they are carefully guided. In the event that you do have to show a group how to solve a problem all the way through, I've found it is very effective to have that group then present the solution to other groups (likely to be equally blocked).

• Beyond the use of groups itself (which I think is critically important) the issue of recitation structure and this sort of collective presentation is one that I feel is a matter of style. Some professors I know do recitation where the groups actually present their homework to the other students at the board. This works for them and their students. I myself have all the groups work on all the problems in their groups while I (and sometimes a well-coached teaching assistant) wander around and answer questions, help unblock a group that has worked on a difficult problem a while and reached a frustrated state, and tell or listen to funny stories. Most groups quickly compare solutions on the easier problems (helping out any within their groups that didn't get them before recitation) and dig into the more difficult ones collectively. With your encouragement and a weekly quiz drawn quite directly from the homework, they quickly learn that to come to recitation with the homework completely unprepared is to invite grade disaster, even as they learn that it is all right to come with a few problems they couldn't get on their own, especially the more difficult ones.

• I openly encourage the students to work on their homework in groups in one or more of their three passes, to have weekly ``physics study pizza parties'', to attend a grad-student-run weekly help night. I explicitly prohibit having any solutions to problems present that they did not work out themselves when students seek help or work on homework. Encourage them to make studying fun any way that they can, and help out by making those parts of the course you control as much fun as possible. Note that memory formation is controlled by the Amygdala in the brain, which is its emotional center. If students are having fun and study is a positive and participatory experience, they will remember more of what they study, and retain it longer.

• Working homework without solutions present is essential, and is a policy that needs to be followed by the instructor and teaching assistants as well. If a student comes and asks for help with problem 8 in chapter 6, I solve it with them on clean paper and never look up a solution or refer to a worked out solution or open a textbook to do it. If (as very rarely happens) I get stuck on a particularly difficult problem, I let them watch as I get myself unstuck. Working with them in this way gives the students the confidence that it is possible to learn the material well enough to do any or all of the problems in the book cold, and makes the help process far more interactive than presentational. Avoid presenting homework solutions non-interactively (e.g. at the board, lecture style) like the plague, although with exceptionally weak students or particularly difficult problems there is sometimes little choice.

This is probably more ``help'' with structuring the course than you wanted or needed, but I think that it is important for instructors to think about how the brain learns, how memory formation occurs, how to build both ``conceptual understanding'' and problem solving skills. The methodology outlined above is certainly not the only way effective teaching can occur, but it works for me and (more importantly) for my students who are generally very satisfied with the courses I teach completely in this way. With all but a very few exceptions (consisting mostly of those students inevitable in any class who just don't want to be there and can't be bribed, cajoled, or teased into working hard and having a good time while doing it) students come out of the class proud of their level of mastery. The satisfied group includes, surprisingly, most of the C students as well as the A's and B's.

That's when you'll know that your teaching methodology (using this book or any other) is successful. When you can give a student a relatively poor grade and have the student agree that it is fair and that the course was still worthwhile, you're doing about as well as one can do. I wish you all the best of luck in your quest to be the best teachers you can be, by helping your students be the best students they can be.