What physics teaches you

I've been talking to people outside of physics and a topic that has come up fairly regularly is what general skills does physics teach you. I've spoken with a couple people with bachelor's degrees in physics who are now working in software and they said that physics teaches you systems level thinking. I guess that's a good answer if you're applying to a software job. But I feel like "systems thinking" isn't the most satisfactory answer. If that was all you learned from physics, I don't see why you couldn't study another subject. There must be other academic fields that teach big picture thinking.

So I'm going to try and give my own answer. "What does physics teach you?" Physics prizes knowledge that is universal, enduring, and predictive; information that is too idiosyncratic and transitory is considered "uninteresting." [1] When you study physics, you assimilate these values. You can scan information and pick out the things that are universal and enduring and things that are idiosyncratic and transitory. The former you pay a lot of attention to, and the latter you assign low priority. When you're unsure how to categorize piece of information, you instinctively look for sanity checks.

In general, all serious academic fields value universal, enduring knowledge. However, there is one difference. Physics can predict the future. Physics possesses a bounty of beautiful and (most importantly) wildly accurate mathematical models -- where if you have enough information about the initial state of the system, you can make specific, quantitative predictions about how the system evolves. No other natural or social science has had this kind of success. And having all these successful, sophisticated models leads to a deep understanding of nature. When you study physics to a sufficiently high level, you experience the nirvana of deep understanding. [2] It's hard to become a deep thinker if you don't know what deep understanding looks like. So this is the gift of physics. It's the quantitative field of study that makes deep understanding most accessible. [3]

Studying physics molds you into an efficient, discerning, deep thinker. [4]

[1] Physicists (in my experience) also tend to be pragmatic, rigorous, and suspicious of hype. They're after the truth and reluctant to say things they're unsure of.

[2] If you're like me, that feeling is intoxicating and you want more of it!

[3] You could probably argue that some types of math lead to the same kind of deep understanding and thinking.

[4] When I took freshman physics in college, I picked up these impressions and got a taste of "deep understanding" which is why I ended up majoring in physics over other subjects. I sensed something greater than myself, that transcended human experience. It was a transformative experience and I wanted more.

A physicist encounters the curious laywoman

While at a recent physics conference, I met a 54 year old Southern woman who asked me lots of questions about what physicists do and whether physics had anything to say about the existence of God. I was trying to grab a quick dinner in the hotel sports bar and she was at the same hotel for a homeowner's (?) conference. We talked for an hour. She seemed a little drunk because she'd forget facts I had told her. Sometimes she didn't seem to quite understand what I was trying to tell her. Nonetheless, I did my utmost be respectful and sympathetic and I think I did a good job for public relations between physicists and the public. She thanked me many times for taking the time to talk to her.

Later, I described this episode to a physicist friend and he thought the fact she asked me the "existence of God" question shows that the public doesn't know anything about the boundaries of scientific inquiry. In his opinion, it would be like asking "are there any paintings that are unartistic?"

So maybe ... because of the abstractions and the high level education required to experience scientific research, the public doesn't have any intuition for what questions scientists ask. Or maybe it was legitimate of her to ask about God and physics? I'm not sure.

How to do theoretical physics

I talked to a few of my colleagues about what to do when you are stuck. Here is a compilation of their suggestions.

Every theoretical physics PhD student reaches a point where mindless cranking and/or doing what their advisor tells them to do doesn't work anymore. This is a hump that the student must learn to get over. Typically the advisor doesn't know how to solve the problem either. If the advisor sat down for a week and thought about it, he/she could probably solve it, but of course, that's not what happens. Either the student solves it or the project is abandoned. Smetimes the student shows the advisor why the project is too hard.

If you are stuck:

• Read the literature. Work out all the equations in the papers, and keep your work in a notebook.
  
• Talk to lots of people. Be aggressive. It is especially helpful to talk to other students because they are at your level.
  
• Figure out why you are stuck. If you quit the project, as least you know why. Sometimes you go around in circles because you don't even know why you are stuck.

Sometimes, there's no problem to solve, because it's been solved already and only a very serious publication search recovers it. Sometimes, it's very hard to find the paper where your problem was solved because many years ago, people used different language. One way to avoid this is to find some people who are experts on the type of problem you're working on, and ask them. This could be tricky, because you don't want them to steal it from you, but if you do it in an advanced stage it would probably won't happen.

A good theoretical physics PhD advisor sees his/her students multiple times during the week. Some advisors likes to pop into their student/postdoc's office and provide "moral support". If your advisor doesn't have time, it's a good idea to email him/her to talk about the project between meetings.

You shouldn't be spending all your time hammering away at one problem. Classes are over, so you should spend time talking to other people and learning about other things. There is nothing to feel guilty about. This is why you are in academia!

For the PhD student, there should be a balance of what they are good at and not good at. If a student is naturally good at numerics, he/she should do some analytical work and vice versa if the student is good at analytical work.

Remember: theoretical physics is hard!! The purpose of theoretical physics PhD is to prove that you can do theory research. Unfortunately, not everyone can pass this "test."

Essential skills for a scientist

I was having a conversation with someone who wasn't sure what he wanted to study in physics graduate school. He was worried that if he chose one field, it would be very hard to make progress, but it would be important work, whereas if he chose another field, it would be easier to make fast progress, but the work might not be so fundamental.

I wasn't sure what to say, so I advised him to take a different perspective:

"Another way you could make a choice is to think about what skills you want to acquire. You want to have the skills you need when the exciting development comes along, so that you can jump into it right away."

Wolfgang Ketterle, an atomic physicist and 2001 Nobel laureate, himself said that skills are important.

Changing fields was a crucial experience for me. Amazed to see how much of what I had learnt before could be applied within the new field, I realized that general skills are much more important than specific knowledge. I thought it would take a long time before I became productive in my new environment, but within months, graduate students who had been working in this area for much longer came and sought my advice and leadership. This experience gave me the self-confidence to venture into new areas, and provided the impetus for my later decision to come to the United States and start once again in a new field.

(Quoted from the Nobel Prize website autobiography)

The question is, what are the important skills for a scientist to learn? I can think of a few:

• Asking important questions and picking good research problems, i.e. ones that are solvable and interesting.
  
• Understanding the big picture and being able to pick out what is essential and interesting from a mess of details.
  
• Turning a relatively vague and abstract research question into a concrete calculation or an observable quantity that can be measured in an experiment.
  
• Writing (papers and grants)
  
• Speaking
  
• Managing and training (teaching) students
  
• Collaboration skills
  
• Life balance and project management
  
• Programming skills
  
• Math skills

In addition, for an experimentalist in physical science, it is also important to know some signal processing. (My sister contributed a few items on the list.)

Flesh may freeze and stick to cold surfaces

This is a real figure in the Oxford dilution refrigerator manual.  Similarly, don't stick your tongue on cold surfaces.

Confessions of a converted lecturer

I watched "Confessions of a converted lecturer", a special talk on science education by Harvard physics professor Eric Mazur. The talk started a little slow, but became very interesting at the half hour mark. Well-worth watching. Here are my notes from the talk.

Prof. Mazur taught the introductory physics course at Harvard. It was mostly aimed at pre-med students, but unlike most pre-med physics classes, it was calculus based. The first year he taught the course, he went to a colleague who had taught it previously and asked him what textbook to use. The colleague said, "Halliday and Resnick", so Mazur assigned that as the text. But now that there was a textbook, what would he say in his lectures? The colleague had mentioned some other books and one of them was out-of-print. So Mazur thought, "Perfect! That's the book I'll use." Mazur would then spend 10 hours preparing each lecture out of this out-of-print book. When he first stated teaching, he thought he was a great teacher because the students did well on the tests and because he got good evaluations. Mazur provided photocopies of his lecture notes for the students and consequently, a few students complained that "Prof. Mazur lectures out of his lecture notes!"

This made Mazur realize that lectures focus on delivery of information. This was certainly important before Gutenberg invented the printing press, because lecturing was the only way to transmit information to the next generation. But now with books and internet, teachers should focus on assimilating information. Education is not just about information transfer. Students need to build mental models. After all, in a Shakespeare class, you don't have the instructor reading Twelth Night to the class. The students are expected to read the play before coming to class.

Meanwhile, Mazur came across a study on the effective of physics teaching. The study gave a so-called "force concept inventory" (FCI) test to the students before and after the course. An example question is: "A light truck and a heavy truck collide. How do the forces they exert on each other compare?" Possible answers are "A) The light truck exerts more force than the heavy truck, B) The heavy truck exerts more force than the light truck, C) The forces are the same, D) There are no forces. The trucks are just in each other's way." The correct answer is (C), using Newton's Third Law.

The student data was divided into four groups: students who had award-winning teachers, students in small instruction groups, students who had experienced a lot of hands-on demonstration in their class, and students who had teachers with the worst evaluations. There was little difference between the FCI pre-test and post-test scores. In fact, it made no difference what group the students had been in! All the students failed to learn basic physics concepts.

Mazur thought, "Well, I teach at Harvard" and wanted to prove the study's results wrong. He gave the FCI to his students at the beginning of his course and found that most of his students scored below 23/29. A score below 23 indicates Aristolian thinking and a failure to grasp Newtonian concepts. Then he gave the test at the end of the course. There was a little improvement but still over half the class scored below 23. Many of these students had scored 5's on the AP Physics exam.

You can define a statistical "gain" to characterize the student's improvement due to the course. If you plot Harvard's results along with data from other colleges, you find a gain of 23% which is much lower than the maximum possible gain of 100%.


Mazur considered various possibilities. Bad teacher? NO. Dumb students? NO. Blame the test! So he wrote his own test. He designed his exam so that each "conventional" question would be paired with a "conceptual" question. The conventional question was one you would find in a traditional textbook. The conceptual question was word based with no numbers or algebra. Moreover, he chose to do this on a topic that students had very little pre-existing intuition: DC circuits. For Newtonian mechanics, students might have real world experience that interfered with their reasoning. This could be avoided by testing them on DC circuits. An example paired conventional and conceptual question are shown below.

Conventional question


Conceptual question


Mazur found that the conventional questions gave misleading impressions of the students's performance. He had expected that conceptual question to be really easy, compared to the conventional question which requires cranking out a page of algebra. Any physicist can solve the conceptual problem in 30 seconds, with 5 seconds on parts (a)-(d) and 25 seconds on part (e). But the students freaked out on the conceptual question. The average score on the conventional question was 6.9/10. The average score on the conceptual question was 4.9/10, with a huge peak at 2/10. The students had been tripped up by the following fallacy. They thought that when the switch was closed, the current would be divided equally between the two paths (the wire with the short circuit and the wire with the light bulb). Therefore, they had all gotten part (b) correct, which is what resulted in the huge peak at 2/10. Mazur examined the correlation between the conventional question score and the conceptual question score. Students who did well on the conceptual question tended to do well on the conventional question. However, the converse was not true. Students who did well on conventional question did not necessarily do well on the conceptual question.


He realized that students were simply learning by "plug and chug", recipes, and memorization. No wonder people often complain that physics is boring! Physics is boring because students apply recipes they don't understand to solve problems. The way students try to solve problems is to look at the "problem solving strategies" box in the textbook. If that doesn't work, they find a worked problem and try to substitute the numbers. There is no real understanding of the concepts. Unfortunately, in physics, recipes only work sometimes. If a recipe only works for 75% of the textbook problems and not for the other 25%, then students get frustrated.

Imagine that you are in a room of 150 students taking an exam. As you turn the page to the first problem, you see the conventional question with the circuit diagram we just discussed. what is your first thought? Kirchoff's Law problem! So, in a split second, you have already determined the appropriate recipe to use and there is no physics left. It's become an exercise in algebra. But do students actually understand Kirchoff's Law? Clearly not, because they did poorly on the conceptual question. [My comment: Physics has turned into zoology! We just classify problems by which recipe applies to them!]

Mazur was at a loss. But then he remembered what happened after he gave the class the FCI. The students were appalled by their poor performance and wanted Mazur to go through the test question by question. He didn't have time to do that in class, so he reserved a lecture hall at night for discussion. Let's go back to the question about the light truck and the heavy truck. Mazur's first explanation was "use Newton's Third Law, done." The students looked utterly confused. So he tried again. The second explanation was "a = F/m, so even though the forces are the same, the heavy truck experiences less acceleration and feels less from the impact." Still, blank looks. Then Mazur gave up and told the class to discuss the problem with their neighbors. Chaos ensued.

He realized that students have a much better idea of what difficulties their classmates are having. The instructors learned the material so long ago, that they have forgotten these difficulties. Education is a two step process: 1) information transfer, 2) assimilation of the information. Therefore, we should give students more responsibility for gathering information.

Mazur now uses a peer instruction style teaching method. Peer instruction includes 1) pre-class reading, 2) in-class instruction focusing on depth, not coverage, and 3) ConcepTests. Each ConcepTest follows the sequence: 1) Question, 2) Thinking, 3) Individual answer, 4) Peer discussion, 5) Revised/group answer, 6) Explanation. In practice, this is how it works. The lecturer will put the question on the projector and ask the class to think about it individually. Then each student has a "clicker" and electronically selects an answer from multiple choice. After that, the students pair up and try to convince their partner that their answer is correct. Finally, the students answer the question, possibly changing their answer after the discussion. Since the instructor can see the distribution of the answers, he/she gets feedback about the class's understanding and can adjust the instruction accordingly. Thus, instead of a traditional lecture, the class becomes ConcepTests interspersed with snippets of demonstrations and the lecturer talking.

The benefits of peer instruction are that 1) there is little time to goof off, 2) there is two-way information transfer. The instructor can assess student understanding and the students can assess their own understanding without any impact on their grade.

Other colleges besides Harvard have implemented peer instruction and the results are astounding. The overall gain is 0.48 for peer instruction compared to 0.23 for traditional lecturing. Moreover, the gains are not instructor dependent.


What about problem solving? Mazur decided to stop doing example problems in class. He felt like he was simply writing the textbook on the board. Think of the following analogy. You don't learn the piano by listening to CDs.

Previously, Mazur had said that better conceptual understanding leads to better problem solving, but the converse is not true. He showed data proving this point. Since he never repeated any questions on exams, he decided it would be safe to give the exam from his traditional 1985 class to his peer-instructed 1991 class. The 1991 students did statistically better on the test than the 1985 class.

In retrospect, Mazur thinks that courses should be defined not by content, but by learning outcomes. For example, for a course on mechanics, a learning outcome could be "understanding Newton's three laws." Unfortunately, Mazur has surveyed his colleagues, and there is no consensus on learning outcome.

The audience had many questions about the practical implementation of peer instruction. Mazur said that preparing the course still takes the time, but instead of making lectures, all the time is put into writing good ConcepTests. You can develop good questions by 1) looking at mistakes on exams and 2) asking for feedback about what was confusing on the reading. For each reading assignment, Mazur has students answer two questions on the material and give feedback on what was confusing. This accounts for 10% of their overall grade.

Also, Mazur has found that it is better to reduce coverage of material. The traditional lecture course covered way too much. The peer instruction course covers less material, but the gain in understanding far outweighs the small loss of coverage.

He also tries to motivate the students by writing exams with conceptual questions. In fact, the first exam is completely conceptual. As he puts it, "it's amazing how students are driven by the exams." He also makes all the exams open-book. After all, in reality, people don't memorize. They look up information while they are solving problems.

Someone asked about labs. Mazur said that because of overcrowding, his students took lab biweekly. One half would do it one week and then the other half would do it the next week. He once gave an exam involving circuits and it turned out that because scheduling, half the students had done the circuits lab before the exam, and the other half were going to do the lab afterwards. The lab made no difference on the exam performance. In fact, the students who had done the lab did a little worse than the ones who hadn't. This just goes to show how cookie-cutter and badly-written the labs are. Mazur has just now started on the huge project of revising the labs.

The audience pointed out that students and colleagues will resist peer instruction. Students have two main complaints. First, there are the students who did well on conventional problems (5's on AP Physics exam), but do poorly on the ConcepTests. They try to blame the instructor and ask "when will we do real physics?" Second, there are students who write on the course evaluation, "Prof. Mazur doesn't teach us anything! We have to learn everything ourselves!" They are mad because they are paying $47,000 a year to be taught by their peers. Mazur tries to convince them by showing them the data and telling them anecdotes. As for colleagues, Mazur said that schools outside Harvard have implemented peer instruction and when his colleagues go to visit those places, they encounter peer instruction and warm up to it. As Mazur put it, "change comes from outside." Mazur had very little influence on "evangelizing" his colleagues about peer instruction. The point is that students and instructors have very deep rooted conceptions about how they learn.

To summarize, traditional indicators of success (class evaluations, exam scores) are very misleading. Education is no longer about information transfer; it's about how to use information.

My comments: I think the success of peer instruction is simply an illustration of ratios. Physics is a very difficult subject. In an ideal world, everyone would have an amazing tutor who would teach them one-on-one. But that is far too expensive, so we have these huge lectures in college. Peer instruction leverages students as teachers.

If I were the "smart" student in the class, I would object to peer instruction. Why should I come to class and have to teach my classmates while not learning anything from them?

The truth is that college is about learning how to teach themselves. What an instructor can do is show you how to approach the problem, what are the right questions to ask. In learning, just as in research, asking the right questions is 75% of the battle. In a sense, peer instruction helps students learn how to teach themselves, because they are forced to teach someone else and explain their reasoning. It's just like what all teachers say; they understood the material much better after teaching it.

I think one thing that Mazur fails to mention is that we still need teachers to inspire students. Difficult abstract subjects like math and physics benefit the most from an inspiring instructor.

Dave Pritchard on physics education

I've always found the topic of teaching and learning fascinating. Yesterday, I went to a talk by Professor David Pritchard of MIT. He helped develop the Mastering Physics software that is used in many American universities today. Back in the early 2000s, it wasn't called Mastering Physics, rather it was Cyber Tutor and piloted in the MIT freshman physics classes. I took notes during Prof. Pritchard's talk.

• Students spend the most time and learn most from homework (education experts and parents agree on this point!). However, homework is the bottom priority for most professors.
  
• Cyber Tutor acts like an expert physics tutor. Prof. Pritchard showed statistical data that proves the software is as effective as a real-person tutor. If a student is completely lost on a problem, he or she can ask for a hint. If a student answers incorrectly, the software can provide feedback such as "check your units."
  
• A goal of software like Cyber Tutor is to teach students multiple representations of information and multiple approaches to solving problems. Experts know all of this, but they usually don't communicate this knowledge. Rather, they focus on the one fastest way to the answer.
  
• Cyber Tutor can track learning trajectories. Each action can be logged: FA = first attempt, SA = second attempt, NF = no feedback to wrong answer, F = feedback to specific error, H = hint, S = subtasks, FS = failed subtasks. An example trajectory would be H → FA → F → SA.
  
• The software is a treasure trove for data mining. In addition to assessing a student's skill, data can also be used to fix badly written problems.
  
• Prof. Pritchard posted his "cheaters never prosper" plot. I didn't understand any of the statistics terminology, but the graph proved that students who copy the most do the worst on the exams. The cheaters are detected with the following criteria -- 1) Response is under one minute, 2) Response is correct.
  
• Interestingly, copying had very little effect on conceptual learning. This is probably due to the fact that class attendance was required and the majority of class time was spent on conceptual learning. Of course, copying had a huge negative effect on analytical learning.
  
• In another example of how detailed data mining can get, Prof. Pritchard showed a plot of percentage of homework completed vs time before homework's due date. As one would expect, the copiers did very little work until close to the deadline.
  
• Men cheated more than women, and business majors cheated more than other majors. I didn't get the exact statistics unfortunately.
  
• Conclusion: It is clear that copying has a large negative effect on learning outcomes. Therefore, professors should discourage copying. This has in fact happened at MIT, partly through eliminating second semester pass/no record grading.
  
• The last part of the talk was called "what should we teach?" Unfortunately, I had to leave and go to another talk, so I didn't find out the answer.
  

Quote of the day: Anders on the "perfect throw"

In a flashback before the nuclear bombing of the Twelve Colonies, Anders, a star professional athlete, is interviewed by a news reporter. She congratulates him on his Hall-of-Fame worthy career. Then she asks him about how he feels about the fact that he hasn't won a championship yet.

If you want to know the truth... I don't really care about the stats. Or the cup, or the trophy, or anything like that. Um, in fact, even the games aren't that important to me, not really. What matters to me is the perfect throw... making the perfect catch... the perfect stepping block. Perfection is what it's about. It's about those moments when... you can feel the perfection of creation. The beauty of physics, the wonder of mathematics. And all the relation of action and reaction. And that is the kind of perfection I want to be connected to.
- Samuel T. Anders, "Daybreak, Part I," Battlestar Galactica

I love this quote. It's beautiful. It encapsulates how I feel about life. The moments matter more to me than the end result.

I play hockey for that magical moment when I see the puck, I know I'm going to get it, I know what I'm going to do, and everything happens the way I planned without conscious thought.

I do physics for that moment when I'm working with a colleague and I'm overwhelmed by the spiritual experience of sharing such intellectual passion.

This is a tangent, but I thought I'd mention a special moment for me. Many of my undergraduate physics classes were taught by these brilliant particle theorists. I remember one day, sitting in class, tuning out the lecture and just marveling at the professor's genius, passion, and gifts of communication. But it wasn't just that one guy, there were four of them!

Link of the day: The Atheon

I recently read about the erection of a "temple to science" called the Atheon in Berkeley, California. It sounds pretty cool. The artist used WMAP cosmological data in stained glass windows!

There is also an official site for the Atheon, but there isn't much information there yet.

Link of the day: Five best data visualizations of 2008

I enjoyed this post about the five best data visualizations projects of the year 2008 from flowingdata.com. Every scientist has the problem of visualizing data and wants to go beyond the usual 2D line graphs, 2D contour plots, and 3D graphs.

The anthropologist in you might like "I want you to want me" exhibit, shown in early 2008 at the Museum of Modern Art. Surely, anthropologists are having a field day with all the social data from today's internet. The Radiohead "laser" film is pretty cool, too. I think I can see the diffraction patterns from the lasers.

Link of the day: Concise explanation of quantum computation

A few years ago when I first started this blog, I tried to write up a layperson's explanation of quantum computation. Anyone who works in the field of quantum computation has to come up with such a speal. My experience is that people get lost when I try to talk about quantum computers. Nowadays, I just tell them that I work on superconducting circuits: "We fabricate circuits on chips just like your computer chips and then we put the chips inside really cold refrigerators."

Michael Nielsen, a co-author of the standard quantum computation text, offers his less-confusing but sufficiently-complex explanation of quantum computation. The idea of visualizing the information as a list of numbers is a good idea. Maybe I can use Nielsen's explanation to tell people what I do, instead of simply saying that I work on superconducting circuits.

Undergrad community in the Carleton physics department

A few years ago, I complained about the lack of community in my department. This morning, I read a post by Prof. Melissa Eblen-Zayas about the undergrad community in the Carleton physics department. Carleton College is a prestigious liberal arts college in Minnesota.

In particular, she notes the distinction between tightly knit and loosely woven communities. Tightly knit means the stereotypical hard core physics majors who do all their problem sets in the student lounge until midnight and try to sneak into lab to get more data. (I know, my undergraduate department was like that.) Loosely woven means people who just do physics as a major and spend time on other extracurricular activities, for example, being on an athletic team or being part of a theater group. Prof. Eblen-Zayas thinks there should be both a tightly knit and a loosely woven community in her department. She speculates that women science majors prefer a loosely woven community, so they end up choosing a major like biology or chemistry instead of physics. I'm not sure if there's room for two types of communities in a small school like Carleton.

I was always part of a tightly knit community from birth (nuclear family) to college (my living group, undergrad physics department), so I have always preferred my work and social circles to be tight. Maybe that's why I had problems in grad school. Our department is loosely woven, though some experimental groups can be tight. I'm getting more used to the loosely woven scheme, though I can definitely say that tight knit is a better fit for me.

Ferrite beads suppress high frequency noise

Via Lifehacker, I read about using ferrite beads to stop cell phones from buzzing during exposure to high frequency noise. I had no idea that ferrite beads are commonly found in USB cables.

That made me curious about ferrite beads. Since ferrite is magnetic, the bead probably acts like an inductor or an inductor in series with a resistance. Maybe with an L/R time constant?

Link of the day: "The Ultimate Code Kata"

At Coding Horror, Jeff Atwood writes about "The Ultimate Code Kata." To quote a quote from his post:

Contrary to what you might believe, merely doing your job every day doesn't qualify as real practice. Going to meetings isn't practicing your people skills, and replying to mail isn't practicing your typing. You have to set aside some time once in a while and do focused practice in order to get better at something.

I know a lot of great engineers -- that's one of the best perks of working at Amazon -- and if you watch them closely, you'll see that they practice constantly. As good as they are, they still practice. They have all sorts of ways of doing it, and this essay will cover a few of them.

The great engineers I know are as good as they are because they practice all the time. People in great physical shape only get that way by working out regularly, and they need to keep it up, or they get out of shape. The same goes for programming and engineering.

The way I interpret this idea is that quality of practice matters over quantity. As Atwood says, you have to be focused (you are telling your mind "I'm practicing this skill right now") and you have to find ways to challenge yourself. Frequently, physicists will think of small problems and try to work them out. I talked to one of my fellow grad students once and he said that when he was tired of research, he would practice programming in Mathematica. For example, he would try to have Mathematica compute the prime numbers between 500 and 1000.

Off and on, I practice hockey shooting by shooting off a board into a lacrosse net. I realized that I didn't want to keep shooting from the same position, so I tried various challenges like moving the board, shooting off balance, shooting from an extended reach, shooting from a squeezed reach, trying to shoot as high as possible, picking a corner to shoot at, etc. I think this is an example of "kata."

Why not?

I remember talking to a postdoc about quantizing electrical circuits. I felt like it shouldn't be allowed. His response was "why not?"

I've been listening to the new South Pacific recording for the 2008 Broadway Revival. It seems odd to listen to such a sweepingly romantic, optimistic score in our age of discontent, a time when darkness is in fashion. But why not? Hope is one of the few things we have. I don't mind singing "I'm as corny as Kansas in August/I'm as normal as blueberry pie/No more a smart little girl with no heart/I have found me a wonderful guy!"

I was watching a Q&A video with Lucy Lawless, the actress who plays "Number Three/D'Anna" on Battlestar Galactica. A fan asked: "As someone whose characters have pushed the boundaries of sexuality on television, what are your thoughts on the D'Anna/Caprica/Gaius threesome scenes?" Lawless's response (in a New Zealander accent):

Oh, I don't really think they went far enough. I mean, there was so much stuff. You know, D'Anna is really handy with the tools ... the power tools, did you see that? That egg beater that she stuck in Gaius's head? And then in the next scene, she's snuggling up to him. What is up with that? Uh, what are my thoughts on that? Really? Truthfully? I don't know. I don't care. People do whatever they want. They're grownups, right? And if those are the kind of people who are going to have threesomes, then it's my job to portray it. (laughs) If Ron Moore tells me to get in bed with Number Six and Gaius... gonna do it! I mean, think of all the other people they could have said... "I want you to get in bed with Eddie and Hoags." I mean, I've always had a thing for Michael Hogan, but... come on.

Besides the video being hilarious, I think Lawless's opinion is a good example of the "why not" attitude. That being said, Battlestar Galactica is a TV show which is not appropriate for children.

Lawless is more well-known for her title role in Xena: Warrior Princess. She didn't expect to run around in a skimpy outfit, swing a sword, and become a lesbian icon (Lawless herself is heterosexual), but she embraced the role and her lesbian fans. My impression is that Lawless (the person) does these outrageous performances, embraces fun and adventure, yet stays grounded. Despite being a sex symbol, she won't post nude. And she took quite a few years off from her career to raise a family. That is a cool attitude, in my humble opinion. There is something to be said for embracing things that are outside your comfort zone. Michael Cerveris, a Tony-award winning actor, says he always takes the acting jobs that "scare him."

If it's not forbidden, if it doesn't hurt anyone, why not?

Perspective on a successful physics undergraduate program

Many people, including myself, have remarked on what a great experience we had as physics majors in my undergraduate program. In this post, I explore why the program was so successful.

First, there was a core group of professors in the department who loved undergraduates. There were faculty who liked to hang out with undergrads and talk to them. Some of them were really charismatic, funny, and inspiring. Those guys (no gals unfortunately) were our heroes. The last year I was there, a professor, who I had previously worked with on a research project, came to me with the idea of having the physics undergraduates pick one of the colloquium speakers. I was Society of Physics Students (SPS) president at the time, so I jumped on the idea. Apparently, the physics majors are still inviting colloquium speakers five years later, so the idea must stuck. This sort of stuff happened frequently. An enthusiastic professor and an enthusiastic student working together to make something happen.

There were a few faculty in the department who were always thinking of ways to get undergrads involved. That way of thinking was highly encouraged at our institution in general. I think that when I was an undergraduate there, the institution was in the middle of a 10+ year campaign to improve the undergraduate experience. (I think the university leadership is pretty happy with their work and now they're trying to improve the graduate experience.)

There was a lot of incentive for professors to be nice to the undergrads in their classes because there was always "free" institution-wide funding to hire undergraduate researchers. In fact, if you were an assistant professor in the physics department at our institution, your chances of getting tenure are highly enhanced by hiring a bunch of super-bright undergrads to do your research for you.

Teaching in the physics department was highly emphasized, to the point where apparently there were young professors tenied tenure because they didn't teach well enough. (I guess the chair and associate chair of the department at the time were super-pro-undergrad-education.) For most courses, lectures were taught by one professor (frequently junior faculty) and sections were taught by another professor (frequently senior faculty). So that doubled our exposure to the faculty. It was not unusual for the senior professor teaching section to sit in on the junior professor who was lecturing. The culture seemed to be that the senior faculty demanded great teaching from their younger colleagues. It was also apparent that the faculty discussed teaching amongst each other and that they would trade ideas and use each other's notes.

Having a great physics department for undergraduates is wonderful, but there are costs. Our classes were so hard that everyone had to work together or go to office hours or both. So our lives really revolved around the physics major. I'm not sure if most undergraduates want to have that kind of life.

The postdoc I worked with complained that he was short-changed. He claimed that there was too much attention devoted to undergrads and that the grad students and postdocs suffered. I was also under the impression that the faculty were overworked since they wanted to (or were expected to?) do both great research and great teaching. The fact that great teaching was expected for tenure probably scared off a lot of potential job candidates who just wanted to do research.

Is it possible to have a department that is good to everyone? I don't know. But if you want something to happen, you need great leaders with a vision and a culture that fosters that vision.

Compass project

The Compass project is a program for UC Berkeley undergraduates whose objective is to increase diversity in the physical sciences. It was partially born out of Joel Corbo's frustration with the undergrad physics program at Berkeley, described in this post. It's a pretty cool idea and looks like there is a lot of energy in the project.

Link of the day: Lockhart's Lament

Michael Nielsen posted a link to the wonderful essay "Lockhart's Lament." It was originally written by a mathematician named Paul Lockhart in 2002. He laments the state of K-12 mathematics education in America. I was a bit shocked to realize what a mediocre mathematics education I had, even though I attend some of the top public schools in the country. In retrospect, I realize how rote my math classes were. No wonder I never really liked math as a child. When I went to college, I took physics and my teachers showed me the rich history behind what we were learning, how you could take different approaches to solving the same problem, and how physics was still a growing, changing field. No wonder I became a physicist and not a mathematician.

I feel like even my college math classes were taught in a rather rote fashion. I never really got a feel for how the various facts I learned were inter-related, nor did I understand why these facts were interesting. My analysis teacher mentioned a book called A Radical Approach to Real Analysis by David Bressoud. I wish I had read it; apparently it explains why mathematicians wanted to come up with these obscure concepts like sets and measures.

I really need a good context to understand advanced math. At some point, I just can't handle so much abstraction. I think most people have even less ability to handle abstraction than I do, which probably explains why so many people hate math.

Not that science education is that much better. I remember Bruce Alberts (an author of the famous biochemistry textbook The Cell) saying that he was shocked at how boring his son's high school chemistry textbook was. The only reason that many students learn science and math is because their parents and teachers tell them how important it is. Students probably don't appreciate it until later in life, if they're lucky. I was one of the lucky ones. There are actually a number of prominent physicists working on physics education including Nobel Laureates Leon Lederman, Carl Wieman, and Kenneth Wilson.

Einstein versus the Physical Review

Not many people know that Einstein submitted an article proposing that gravitational waves don't exist and then had his article rejected by Physical Review. There is a nice historical account in Physics Today.

I guess this article shows that peer review has its benefits -- like saving a giant of the field from publishing an embarrassingly incorrect result.

The difference between students and experts in solving physics problems

Here's an interesting remark I came across in the blog Confused at a higher level:

As she said, if you give the same problem to a novice and an expert and ask them to think out loud, you will see a completely different intellectual structure to the approach. For an introductory mechanics problem, for instance, a student will say things like “oh, it’s an inclined plane. I should think about which forces are involved. Wait, is there friction? What about the normal force? What axes should I choose? Oh no, this is a complicated one — there’s gravity and a spring as well.” And so on. An expert will say something like: ‘Hmm, that’s probably best done by a conservation of energy analysis. Ok, which potential energies do I have to track …” And so on. Neither approach misses the point, but the latter constrains you, and focuses you much faster.