Physics 122: Fundamentals of Physics II, Spring 2007 General course information, sections 101-108

Instructor:  David Hammer

Offices:  1310 Physics and 2226 Benjamin
301 405-8188; davidham@umd.edu
Office Hours:  Wednesdays 3-5 in the course center; other times by appointment, or right after lecture.

Books and Clickers: 

Course philosophy

The whole of science is nothing more than a refinement of everyday thinking. Albert Einstein, 1936

This course mainly concerns the physics of electricity and light. Of course, you already have a bit of experience with both, which is a good start. Mostly you know about phenomena; we'll be trying to understand how these phenomena come to be, that is the physical mechanisms that bring them about. For that, we'll start from other things you already know. It's standard practice in physics to try analogies to more tangible objects and phenomena as a way to get a handle on things that aren't so tangible. That's actually the only way we ever come to understand anything new, by starting from things we already understand.

Over the years, for example, physicists have modeled electricity as a kind of fluid, using analogies to water flowing through pipes and stored in containers, or as a mix of two kinds of fluids, or as made up of tiny particles.  And they've thought about light as made up of little particles or as made up of waves, using analogies to waves moving on strings or on the surface of water.   Some students find this hard to accept, the need to think in terms of analogies, because they want to talk about what electricity "really is." But "really is" really isn't an option in physics, and to make progress understanding electricity and light you'll need to learn to use analogies and analogical models. And that's much of what we'll be trying to teach you to do.

1.  Lectures

You are required to attend. Lectures will involve your active participation, including responding to questions I pose, talking about your ideas with other students sitting nearby, along with asking questions of your own. 

Answering clicker questions in lecture gives you credit in the form of "participation points."  You get that credit no matter how you answer, but of course you should try to answer well!  Some students object to this use of clickers, because it's "taking attendance" and they don't want to lose credit for not being in lecture.  That's not the real reason I use them; the real reason is that it's a great way to get you all thinking, and for me (and you) to find out what you all are thinking.  So - you get a point for paying attention and thinking and responding.  I also use them so that everyone gets an easy boost for their grades, to make up for my rather challenging exams.

Now, the fact that the clickers serve as de facto attendance doesn't trouble me terribly, because I think you should be in lecture,but I'm willing to make arrangements on an individual basis.  If you feel that coming to lecture is an undue burden, please come speak with me.  (Of course, it's not ok to send your clicker to class without you.)      

On my part, having required attendance, I take responsibility for making lectures worth your time. If you're finding they aren't, or if you have ideas for how they could be better, please consider it your responsibility to let me know. (No kidding: I need and appreciate that kind of feedback from students, and it's hard to get.)

2. Discussion sections and laboratories

You're also required to attend discussion sections and labs.  These run as an essentially separate course under the direction of Prof.  Bill Dorland, although your grade is all lumped together. At the end of the semester, he'll give me the lab portion of your grade, and I'll incorporate that to find the total grade.  Note that by department policy, you must complete every lab to pass the course.  (There will be a make-up week at the end of the semester for missed labs.)  

During the discussion hour, you'll break up into groups of four to work through "tutorials" that will complement the homework in helping you find and work on the core ideas we're developing in the course.   As much as possible, I'll try to coordinate the lecture schedule with the tutorials.  That's harder to do than you might think, partly because you all have tutorials all week long (so my lecture on Wednesday can't assume that you have or haven't had that week's tutorial) and partly because the tutorial schedule is hard to change as we go.  So - I apologize in advance for when we get out of sync. 

The labs are really about something different — they're about your experiencing physics as an experimental science, and the topics in lab aren't as important as the experience of designing experiments and analyzing results.  So you'll find the topic of lab generally doesn't align with what we're doing in lecture, but that's ok. 

4.  Homework

You are required to do the weekly problem sets, which I'll assign on the web at this address, and your work must be legible and on time.  I don't use WebAssign — you'll hand in your homework in lecture.  I want to emphasize legibility:  The teaching assistants will have a lot of grading to do, and out of consideration for them I insist your assignments be neat and easy to read.  If the TA has to struggle to read your work, you won't get credit for it.   You are also required to read the solution sets I'll write and post on the due dates.  

I'll assign six problems every week, and they're going to be pretty challenging.  Don't expect repetitious work to practice solution techniques I've shown you in lecture!  Expect questions to get you thinking hard about the ideas we're studying and what they're really about.  It will help a lot to work with other people.  (But write up your own solutions, in your own words.)

Please give these assignments your sincere attention!  What I mean by "sincere" is that you use the homework to help you build an understanding of the physics.  To say a little more about that, the reason you work problems in a physics course is not generally because you care about the answers, any more than the reason someone swims laps at the pool is to get from one end to the other.  The reason to work problems in physics is because it helps you find and resolve gaps or inconsistencies in your understanding.  You'll only find those gaps if you're digging around in your own mind--I'll be asking problems to help you do that.  And if you do do that, it will make a big difference in what you get out of the course and how you do on the exams. 

We want you to be using the homework to build an understanding, and we'll assess it accordingly.  Answers alone, without explanation, will receive no credit even if they are correct.  (Of course, the explanation may well be expressed in mathematics.)  However, evidence of a sincere effort to refine your everyday thinking, even without an answer, will receive at least partial credit. 

So... please don't make a habit of asking other people to solve problems for you.  That's like asking someone to swim laps for you--once in a rare while it might make sense, but usually it results only in your watching someone else get some exercise.  For the most part, you should ask for--and expect from the TAs and me--coaching and guidance to help you think things through for yourself. 

The best place to go for help with homework in this course is the Course Center, room 0208, in the basement.  Many students just go there to do your homework, where they find (or, all the better, arrange to meet) other students who are working on the same problems.  We will staff the Course Center with Teaching Assistants - that's where TAs and I will hold our office hours.

And again:  It is very important that you read the homework solutions and compare them with your thinking every week when they come out.  I'll post solutions at this address on the day the homework is due, and they are required reading.  Do not wait to get your homework back to read the solutions!  If something doesn't make sense in the solutions, ask about it - send me e-mail, or speak to your TA.  And if you think I've gotten something wrong, maybe I have!  

5.  Exams

There will be two midterm exams, with the tentative dates:  Feb 28/March 2 and April 11/13, 10-10:50.  (So my tentative plan is for each midterm to have two parts, one for each day.)  And there's a final, scheduled for Friday May 18, 8:00-10:00, according to the standard exam schedule. 

I try to write exams so that memorization without understanding doesn't succeed.  I try not to have any questions for which you can just remember an answer from homework or tutorial or lecture.  I do base my questions on things you've seen, but the way I do that is to ask myself "what can I ask them to find out if they really understood the answer to that question?"  The best way to prepare for exams is to keep up with the course, "refining your everyday thinking" all along the way, rather than cramming at the last minute. When you do study, it's much more effective to do a small number of problems thoroughly--solve each problem several different ways, vary the problem slightly and think about how that would affect the solution--than it is to practice the same technique on lots of different problems.

There will be a mix of questions, with some like the homework and tutorials (requiring explanations for credit) and some like the clicker questions in lecture (multiple choice, with no explanation). 

The grading isn't what you're used to, either:  The average score on my exams is typically around 60%.  No, that doesn't mean the average grade is failing!  I can set the grade cuts however I like.  Generally I aim for an average of 65%, and that's the middle of the C range for grades, and the cut is is 75% for a B, 85% for an A.  But it often happens that average comes out lower, and I adjust the cut-offs to be lower.  (I never adjust them to be higher.)  Typically on my exams, the cut-off for an A is around 85-75%, for a B 75-65%, and so on. 

Here's the advantage of that system:  In the usual way of doing things, exams put a lot of pressure on students to get everything right; you need to have 90% or more if you want an A, 80% or more, etc.   In this course, it's not so costly to your grade to miss questions  — everyone's going to miss questions!  If you draw a blank on some of the questions, you're still ok.  You could, for example, have lots of trouble with the multiple choice questions but if you do well with the essay questions you'd still have a high grade. 

(There will not be any "makeup exams" in this course — it would be a nice thing to do, but there are just too many students for this to be practical.)  

Please note that a point on participation won't equal a point on homework or exams!  I'll add them up in each category and then scale them to count as follows for the total grade.

Participation:  15%.  Participations points are for clicker-responses and tutorial effort.  For the clickers, you get a point per response, regardless of the answer you give, and you'll get I also give students pp's for finding mistakes in my solutions, and there may be other things along the way.  If you feel that you shouldn't be obliged by participation points to attend lectures, speak to me about the option of being graded only on homework, labs, and exams.  

Labs: 20%.  BUT - you must complete every lab in order to pass the course.  

Homework:  15%.  There will be six problems or questions every week. Five of the questions the TA will grade "lightly" - just checking quickly to see whether s/he can follow your reasoning. Those will count for 2 points. One of the six questions will count for 5 points, and those the TA will read more thoroughly.

Exams:  50%.  The final will count for a bit more than the midterms (2/5 of the total exam score).  

I also solicit feedback from TAs about students' work, and in the final analysis I reserve the right to exercise some judgment, to move a student upward if s/he is very close to a grade cut. 

If you have a valid excuse for missing an exam or homework assignment, see me to arrange what to do about it, beforehand if at all possible. You must speak to me not to your TA, to be excused from any requirement. 

Please don't come to me over just missing lecture, or if you've forgotten your clicker — I just can't handle keeping track of all of that!  We'll have about 40 classes over the semester, and 12 tutorials.  Missing one class means a difference of about 1/50th of the participation points, which is 15% of your grade - so that's about 1/300th of the total points for the course.  So don't worry about missing a couple of classes worth of participation points -- it won't have much of an effect on the total. 

We're interested in improving physics instruction, for this course and in general, and in understanding how students learn. To these ends, we may ask for your consent to use videotapes of your work and photocopies of assignments as data for our research, and we may ask you to complete a diagnostic survey or two.  Your answers to any survey will have no effect on your grade in the course — I won't even see them until after the course is finished and grades are submitted.  Nor will it have any effect on your grade whether you grant or decline consent.

I do want to emphasize, though, that aside from using a bit of class time for the diagnostic surveys, everything we do will be out of interest for your learning.  You'll find many aspects of the course are different from what's traditionally done, but that's because we have good evidence that these things are more valuable for student learning.  We're not "experimenting on you"  If you have any concerns at all, please let me know.