Advice For Physics Majors (a serious article, for once)

Knee-deep in physics– the undergraduate physics major

Lemmie blab on for a while now about what the undergrad physics major is like, what classes I found especially useful, and what classes I’d recommend taking (and why).

Are you tough enough?
A big question for someone starting out is, “Can I handle it? Am I cut out to do physics? Shouldn’t I go back to my job as a swimsuit model, and quit this crazy dream?” It’s a notoriously hard major, probably because there just aren’t that many jobs in it, and so only people really driven to do well in physics are going to major in it. And let’s face it, most human brains weren’t meant to think about physics, and it does take some practice to get the hang of it. First of all, I found that the hardest times I had in my major were in the freshman year, in the very first introductory courses. Generally I found that courses didn’t get harder as I moved ahead. The subject matter was more advanced, of course, but I was also more prepared. I found that my abilities pretty much kept pace with the advancing classes. The closest I came to dropping out of the major was in my second quarter in college, and so if you are doing okay in the first year, take that as a good sign. (Note — part of my problem the first year was that my math classes were somewhat behind the physics classes — be prepared for bits of alien math popping up here and there.  We did “double integrals” in physics class before we got to them in math class.)

You know those little logic puzzles that schools throw at you from time to time? Ones that sound like “Charlie is twice as old as Bob, Steve is 14 years younger than Charlie would be at double his age, blah blah blah, How old are all they?” Maybe you’ve taken some math contests in school, or played around with those puzzle books, or have seen these kinds of math and logic problems here and there in magazines (say, Scientific American’s puzzle column). This kind of logical thinking, where you concentrate on some problem until the light bulb dawns and you see the “trick”, is very close to what your life will be as a physicist. There will be very little memorization in your classes compared to other majors. Mostly, you will be solving problems.

Of course, not all of physics will be as hard as these logic games you see here and there, and you will be taught a wide range of skills and techniques to solve the problems you’re given — so it isn’t as if you’ll be constantly asked to solve impossible problems. But this is the closest I can come to describing what you’ll be asked to do from the layman’s perspective. If this isn’t your cup of tea, and it wasn’t mine at the start, you may find a physics major to be rough going at first — it requires some very different skills than what you’re probably used to in high school. For some people used to succeeding on sheer memorization, the physics major can be a rude awakening. But other students really thrive and enjoy this new style of learning, and are eager to get as far away from the rote memorization of other subjects. Keep this in mind when you consider a physics major — while it’s not essential that you be one of those puzzle whizzes who always aces the math contests, you will be expected to develop some of those skills in the major. I was never all that into the little puzzles and math contests myself, and never did that great on any of them, but I found that I had to work on my problem-solving “muscles” to succeed in physics class. So take my encouragement that you too can do it, but also take my forewarning that you will be faced with some radically different thinking than you’re perhaps used to.

How to succeed in physics without really trying
So how do you do well in physics class? There must be thousands of people with millions of dollars behind them with their own theories, courses, tutoring methods, and opinions on how to do well in physics, and I am not going to try to duplicate all the advice they have. If you want detailed advice on how to solve physics problems and how to “think like a physicist”, you’re going to have to check out some other sources of advice or wait for me to get around to writing an essay on the topic. But I will describe generally my study habits, specifically what worked and what didn’t work.

Here is Sean’s Golden Rule of Physics Class:

IF YOU CAN’T DO THE HOMEWORK PROBLEMS, YOU CAN’T PASS THE TESTS!

“Well, Duh!” shouts the peanut gallery. “That’s what homework is for!” But believe me, you will at least once, make the mistake of ignoring this rule. You just will. You’ll have good intentions, but you’ll convince yourself that understanding the lecture, and following along with a couple example problems will be enough. And you will get BURNED. Let me set the scene for you:

[Student, in a dorm study room, 12:30 am, night before a quiz]

Student: “Well, I’m following what he says in lecture. Everything seems to make sense. The example problems he solved in class make sense. I even read the book, and took some notes, and followed along with the problems they did in the book. So I should be all right on the test, I don’t need to do the homework…”

[Fade to test day, student staring blankly at quiz, starting to panic]

Student: “I don’t even know where to begin with these problems! What happened? I followed everything in class! The book made perfect sense! Why can’t I do these problems?????”

Physics Quiz: “BWAAHAHAHAHAHAHAH AAHAHAHAHAHHAHAAAA!!!”

It will be unnerving, almost spooky — you won’t be able to do any of the problems, even though you think you understand the topic just fine. It will be almost like trying to run in a nightmare — you will be certain that you should be able to do the problems, but they’ll be completely impenetrable. You might think the test doesn’t cover any of what was covered in class, maybe even complain to the professor. But that isn’t the problem — the problem is that you didn’t do the homework yourself, you didn’t attempt the problems on your own. You relied on following someone else’s solution, be it the professor’s or the book’s. Trust me, you WILL do this, and you will get a terrible quiz grade from it. You WILL horribly underestimate how well you can solve a problem, based on how well you follow along when someone else solves one.  And your quiz WILL laugh at you.

Why? Because even though a solution to a problem might make sense, coming up with that solution in the first place was the hard part. When a teacher describes how to do a problem on the board, they mask the hardest part — coming up with the method to solve it in the first place. They will show you a few physics equations, and go through some math, and it will all (usually) make perfect sense. But they don’t show you the 10 minutes of staring at a blank sheet, the 20 other equations that they wrote down that didn’t apply, or the 5 dead-ends they started on before they stumbled across the right method to solving the problem. Once you have set up the problem, the rest is easy. 80% of the effort, of the work and time and energy you will expend, will be before you write down a single line of your final solution. For this reason, you HAVE to do the homework! If you are under a time constraint, and you don’t have time to read the book or go over lecture notes, DO THE HOMEWORK. Doing homework is the most valuable effective time you can spend studying for tests, even more effective than memorizing formulas and going over notes. When you’re studying for a test, do even more practice problems — do those problems in the book that the teacher didn’t assign. That’s the best way to study, by far.

Also be wary of coasting on what you remember from your high school classes those first few weeks. If you took some high school physics then the first few chapters will be review, and you might be tempted to ride on what you remember. So you did spend your summer vacation reviewing angular momentum, right? No? Well then you aren’t going to ride very far on what you remember. Do that homework anyway, even if you don’t think you need to. The general concepts are easy to remember, but the skill of problem solving disappears FAST. The duplication of topics my first quarter lulled me into the lowest grade I ever got in a physics class. Here’s what I do when I’m studying for a physics or math test. If I have time, I’ll go back to my class notes and the book to make sure I have a good handle on all the topics. The best way I know to do this is to take notes — I literally take notes on my notes, or on the book. It’s a huge time drain, and might seem inefficient, since when I’m done I have two or three copies of notes on the same subject. But I’m not doing it for the sake of the notes, I’m doing it to force the material into my brain better. For some reason, the act of writing something down makes it stick in your head better. And by forcing myself to take notes, I have to reorganize and clean up my original notes, thereby correcting any mistakes and giving myself a better “big picture” on the topic. It may seem like a waste while you’re doing it, but give it a shot one time — trust me, it is a great memory-improvement trick. Of course it only helps you if you have time. If I’m crunched for time, I skip right to step 2…

I go through all the homework we’ve been assigned, and any past tests, and make sure I can do these problems and similar ones. If the teacher is halfway decent, the homework problems will be a good reflection of what will be on the test. What’s more, most teachers usually drop hints here and there as to what might be a good test problem. Usually, between the hints mentioned here and there, the practice problems done in class, and the homework assigned, I can come up with a short list of good candidate problems that I wouldn’t be surprised to see on the test. I attack those first, making sure I can do these problems without looking at the solutions, and doing new ones in the book if I can find them. I always do this step in my studying, even if I don’t have time to do the little note-taking exercise. Doing your assigned homework, and doing extra problems beyond the homework, is by far your best tool to use for studying for the tests.

And let’s talk about your first homework. You may find yourself getting discouraged at first — you might look at the solutions to problems you’ve been assigned and think, “how the hell was I supposed to come up with that? I just never thought of it!” So true — there are going to be those problems you come across that you just can’t figure out, no matter how hard you study. BUT — with lotsa work, perseverance, and practice, you’ll find that you improve very quickly. After a while, you start noticing that there aren’t that many “tricks” to solving physics problems, and while they may seem completely out of the blue at first, after a while you will learn to recognize them. Your “bag of tricks” gets bigger and bigger, until you will know enough to handle anything that comes your way. It may seem unfair that you are expected to cough up these tricky solutions at a rate of a dozen or so a week, but trust me, it gets easier. The sad fact is that a physics problem that might have been someone’s PhD thesis last century is a homework problem in physics 101 today. But you can do it — just hang in there, make a note of those tricky solutions that you couldn’t get on your own, and remember the tricks for future problems.

Some cool classes
You probably already know what basic physics classes you’re going to be required to take to finish the major, but what elective classes should you concentrate on? That depends on what you want to do with physics — industry or academia? Grad school? Theory or experimental? What area of physics do you want to do? Keep in mind that no matter what you go on to do, you’re going to have to pick a more specific area to concentrate in — everybody from professors to high school teachers to cubicle-dwelling coders have to pick a specialty. Here’s a list of what I think are some useful classes to take, for areas that I know about:

• Extra math and physics: Obviously this is the best to do if you’re going on to grad school. If you want to do pure physics, take as much physics as you can fit in, up to and including graduate and advanced electives if you have time. Probably the single most useful class to prepare yourself for grad school classes would be more math. Very often there is a sequence of courses in “math for physics and engineering”, or something like that. If you can’t decide, pick this, especially if you don’t know yet what specific area in physics you want to do. If you can fit it in and have the aptitude, a minor or double major in math can help.

• Computer programming: It seems like these days everyone has to do some programming in their jobs. If you think you’re going to be a theorist, and sit all day with a pencil and paper, think again — most theorists spend lots of time creating computer simulations of their research. Experimentalists often use programming to control their experiment, and it’s absolutely vital for analyzing the results. I somehow managed to avoid all computer programming classes in college because I didn’t like to program, and that was a big mistake. It’s really no understatment to say that it’s hard to think of a physics-related job that doesn’t involve some programming.

The language? Pick any, and do a decent job learning it. Once you get some experience in one, it’s easy to “translate” what you know to another. All languages have pretty much the same ten or fifteen main concepts in them, and differ pretty much just by where you put the semicolon, or other little “grammar” rules. The really important stuff to learn is programming logic — what algorithms do you use to do some particular task. But C is probably the most common, Java is a growing upstart, and FORTRAN is fading but known for being used in scientific work. Matlab is on the rise.

• Lab classes: I avoided lab classes in undergrad because I thought I was going to be a theorist (see the pencil-and- paper illusion mentioned above). I pushed off the required advanced lab class until my very last quarter, which turned out to be a mistake — it was probably the single most important class I took. Working through a couple advanced experiments (advanced meaning longer than an afternoon to complete) made me realize that I actually enjoyed it, and did better at it than the feeble attempt at theory research I was also doing at the time (see next item). If I’d have given experimental physics a fair shot before this, I would have realized my interest in it much sooner, and could have made up for lost time. At any rate my advice is to try a breadth of classes and experiences as early as you can — don’t put off figuring out what it is you want to do!

• Research: As I’ll mention in the next section, working on research in someone’s lab is close to required to get into physics grad school. And it should be, too — it’s your first exposure to what academic research is going to be like, in grad school and as a professor. The more exposure you get, and the earlier the exposure, the better. If you have to work some low-paying job anyway, why not try to work in someone’s lab rather than sling coleslaw in the cafeteria? This is also your chance to feel out some area of research. Go work for that Institute Of Extremely Complex Theories, and see if you like theoretical physics. Check out the Lab Of Possibly Carcinogenic Chemicals. Now’s your chance to really delve into a subject area and see if you like it, with no regrets or cost if you decide you don’t like it. Don’t wait till your 3rd year of grad school to finally get around to working in that area that you always talk about — if you find that you don’t like it so much after all, the stakes are much higher and the time much shorter to repair your mistake.

• Engineering: I know many of you are probably already in engineering, but I wasn’t. I’ll keep this brief, but let me say that I wish I had taken more engineering — I had somewhat of a bias against doing “applied” courses back then, but now I’ve learned that there is no clear division between physics and engineering. In fact the areas I most enjoy, and that I work in now, are properly labeled as “electrical engineering”. Let me put in a plug here for my favorite scientific area, signal and data processing — check it out, you might like it.

• Statistics: If I had to pick an “underrated” award, awarded to the course that I ignored the most blatantly, that came back to be vitally important later in my career, it would be… computer science.But that’s obvious. I knew I was avoiding programming, I knew it would be important later, I just didn’t care because I didn’t want to be in the computer lab until 6 am on Friday nights. But a close runner-up would be statistics. In fact, now that I’ve graduated, statistics is the first course I went back to re-take as an “adult”. It really does come up again and again, each time taunting you, reminding you how shamelessly you skimmed through that one stats class you were required to take. Consider it seriously for extra coursework, if you have time. I know it’s boring to you, I know it’s a pain to think about, but it’s important. In the immortal words of U2, on their smash hit “Walk On”,

“And I know it aches
How your heart, it breaks
You can only take so much
But… you better know what an ANOVA is if you ever do publishable research.”

(What’s that? You don’t agree with this lyric reprinting? Go back and listen more carefully.)