Students Know What Physicists Believe, But They Don't Agree

ResearchBlogging.orgThis is flagged as a ResearchBlogging post, but it's a different sort of research than I usually write up here, as this is a paper from Physical Review Special Topics-- Physics Education Research. This is, however, a legitimate and growing area of research in physics departments, and some of the findings from the PER field are really interesting.

This particular paper, though, is mostly kind of depressing. The authors, including Nobel laureate Carl Wieman, gave students in three introductory physics classes a survey about their attitudes toward physics. They asked the students to indicate both their own opinion of the question, and also what they thought a physicist would say. They compared the student responses to "expert" responses from a survey of 66 college and university physics professors.

Their main finding was reported in the title: for the most part, students did a very good job of predicting the expert response, agreeing with the real experts roughly 80% of the time. Their personal opinions, though, were considerably less expert-like-- 15-20% less.

Some of this is understandable. The questions with the biggest split between "personal" and "physicist" responses included "I enjoy solving physics problems," and "There are times I solve a physics problem more than one way to help my understanding." They correctly predict that experts will agree with both statements, but less than 50% of them personally agreed (the one anomaly being the ~60% of students from the calculus-based class who agreed that they liked solving problems). Having both taken and assigned problem sets for introductory physics, it doesn't surprise me to learn that students don't particularly enjoy them.

Other findings were also pretty much what you would expect. Students in the calculus-based class agreed more with the experts than students in the algebra-based class (that's code for "Physics for Pre-Meds") or the non-science-majors class ("Physics of Sound"). Students with stronger physics backgrounds (AP or IB physics) also tended to agree more with the experts.

A result sure to be of interest to many people at ScienceBlogs is the breakdown by gender. This produced a slightly odd result: on the whole, women were better than men at predicting the expert response, but their personal answers were less expert-like than men's. I have no idea why this would be the case, and the authors don't appear to be much better-- they basically punt the question with an "additional research is needed" statement.

The depressing result, though, is the comparison of "pre" and "post" scores. Students were given the survey twice, once at the beginning of the class, and again at the end of the class. The "physicist" responses didn't change much, but the "personal" responses actually got worse by almost 7% in the calculus-based class. The algebra-based course managed not to change, but the non-science-majors class also saw the "personal" scores get significantly worse.

So, basically, taking introductory physics classes makes students think less like a physicist than they did before they started. That's a cheery thought to throw at somebody teaching introductory physics.

The paper doesn't try to explain these results in depth-- they're just reporting the findings. They do offer one paragraph worth of speculation, though, which is worth quoting at length:

It appears that the most prominent reasons for students splitting on their responses are (1) believing that physicists would inherently be more interested in physics and aware of physics phenomena, otherwise they would not have gone into the profession, (2) seeing that the greater experience and expertise of physicists would influence their abilities and beliefs, and (3) believing that the kinds of physics problems that students see are less authentic and therefore are perceived differently and approached differently than the sorts of problems a physicist faces, which are seen as being more in depth, involving harder problems, not requiring memorization, and putting more at stake that the student's homework problems. Other reasons expressed in these preliminary interviews include statements reflecting what students see as most sensible for their personal situation: students saying that they are lazy (their words) in their approaches to problem solving compared to physicists; students saying that while they want to or should take the more expertlike approach, in reality they do not because they do not have the time or need; and students believing physicists, or other people in general, may have a different approach to learning than themselves but not wanting to assume what approach that would be.

That seems pretty much dead on, to me.

The frustrating thing about this paper, like most reports of bad educational results, is that it's really not clear what should be done about any of this. They refer to some other work (that I don't have easy access to) showing that students can occasionally be pushed in the more expert-like direction, but don't say how. As an experimentalist, this drives me nuts.

So, I'll throw it out here, for the half-dozen people who read this far: What do you think should be done to improve this situation? Or does it even need improving? Is it just one of those things, and what can you do, Jake, it's Chinatown?

Kara E. Gray, Wendy K. Adams, Carl E. Wieman, Katherine K. Perkins (2008). Students know what physicists believe, but they don't agree: A study using the CLASS survey Physical Review Special Topics - Physics Education Research, 4 (2) DOI: 10.1103/PhysRevSTPER.4.020106

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Actually, I think they left off the main problem. We're talking about introductory physics here, right? I remember being frustrated all through my first physics class at just how UNREALISTIC it all seemed. Everything is a frictionless plane and a wind resistance doesn't exist and all cows are spherical. It seemed so removed from reality, that I think I do remember developing a view of physicists as profoundly out of touch, feeling like my gut was more trustworthy because it allowed for nuance in a way that physics 101 did not.

What would have countered that for me would have been a huge dose of actual, real world examples and results. Almost a parallel history of physics class. Explain the problems as they were overcome, let the students in on the genius of galileo's gravity thought experiment (and by God, make it clear it was only a thought experiment). Set the stage before the publication of the Principia, to show how mindblowing newton's work was.

I remember reading Oliver Sack's Uncle Tungsten, the way he laid out the history of chemical discovery step by step, and going, My God! This is the template for how all science should be taught. I learned more about chemistry (or at least developed more excitement and respect for it) in that book than in 8 semesters of chemistry classes.

"This produced a slightly odd result: on the whole, women were better than men at predicting the expert response, but their personal answers were less expert-like than men's."
Somehow I'm reminded that girls are taking high school physics at higher levels than ever, getting good grades, and yet not deciding they want to be physicists. I wonder if predicting expert attitudes is a proxy for some awareness that also helps you get better grades- I would imagine so.

It's interesting the algebra based course was the only one where the student to expert discrepancy didn't change. I bet a lot of pre-meds go into physics expecting to hate it. But I've known a lot of people taking calc based physics who thought it was going to be great and were very disappointed; and I wouldn't be suprised if the same holds true for non-science majors.

Chad: One of the problems that education researchers have found is that students come to physics classes with lots of misconceptions. Some of the physics education groups have developed concept inventories to identify those misconceptions. The current thinking is that new learning can't really begin until those misconceptions are addressed, challenged, and displaced.

There are curricula that have been designed to confront misconceptions. One example is the Physics by Inquiry package at the UW. This group has a good reputation in the physics community. They won the 2008 APS award for excellence in Physics Education.

I sort of agree with Matt. I think relating the "unrealistic" problems to actual problems that physicists solve is key. And the broader range of problems the better. Also, if the real world really is too complex, you should explain how it would be evaluated by a real physicist. You could even go as far as working out a problem in gory details just to show them -- and then show how the simplistic result is a good approximation, but not realistic. And if frictionless inclined planes seem unrealistic and a waste of time, then we need to come up with realistic situations where the same concept is used and teach that.

I don't necessarily think teaching physics in chronological order is beneficial. I think you can teach the tools they need and then make a comment afterward about how it developed historically. Historical context can be useful, but certainly should not be used as the compass for a course syllabus.

Some ridiculously large percent of students taking calculus-based physics are checking off something for an engineering degree, with another (small!) fraction being future physics majors, pre-meds who got warned ahead of time that this was the class they needed for the MCAT, not the algebra-based one, and other misc majors. Teaching in a way to reach these students and get them to think physically requires tossing out the BS approach such as the current version of Halliday/Resnick/Walker -- that pedagogical approach tries to make it look like like realistic problems are being used but in the end only makes physicists look out of touch.

I had to do a lot to work around the textbook I got stuck with last year. Hyperphysics helped a lot, as did sacrificing a lot of material normally covered for the sake of dealing with examples and techniques typically considered too advanced for such classes but which are actually used in real life for the careers they said they wanted to study for. Newton's laws (both as momentum conservation and as intro to physical description via by differential equations). High-speed video of billiards (momentum conservation and collisions). Videos and problems involving rock climbers and "redneck bungie jumping" (oscillations, elastic materials). Geophones and the differential equation describing them (oscillators in realistic situation). AC circuits and some complex math that goes with them (oscillators for clocks for computers, energy conservation). Solar furnaces for smelting ore in Central Asia (thermodynamics). Amusement park rides (conservation of angular momentum). I've taught one of the few intro classes I've ever heard of where students were exposed to Fourier analysis for physical data (frequency spectra with Falstad's applet), but very quickly in their careers they use it, or hire someone to do it, or using equipment where it's built into the hardware since digitized data is so much more compact than analog data. I gave a homework assignment to carry out numerical integrations. I used John Leonhart's monologues to get them thinking about the first and second laws and the video with the candle not popping the water balloon for material properties.

The traditional approach isn't good enough to get people who just want to check off a box to appreciate how the laws of physics will be important to their future endeavours.

My wife, as a Physics professor, also publishes on Physics pedagogy, and in journals for educators (i.e. "The Physics Teacher").

One of her papers was on the literature about what college Physics students THINK that they know, which is actually WRONG. This typically comes from erroneous lessons and textbooks in High School.

We know a lot about how to teach someone something that they know that they don't know. We know very little about how to teach someone something that they thinks that they do know.

How to solve this? People are not dominated by state variables, but by history variables.

The teacher's priority (assuming that he/she knows the content, and knows how to teach the receptive student) is to understand what is in the mind and emotions of each and every student, match impedences (or define the interface or whatever metaphor you prefer), accentuate the positive, eliminate the negative, and watch out for Mr. In Between.

Chad: One of the problems that education researchers have found is that students come to physics classes with lots of misconceptions. Some of the physics education groups have developed concept inventories to identify those misconceptions. The current thinking is that new learning can't really begin until those misconceptions are addressed, challenged, and displaced.

This paper is dealing with something slightly different, though. The "non-expert-like" responses aren't to physics questions, they're to questions about physics. This isn't documenting problems that students have with Newton's Laws or conservation of angular momentum, it's talking about attitudes toward the science as a whole. Students are leaving introductory classes more likely to think of physics as rote memorization and drudgery than they were when they started.

That's a very different problem than the problems with pre-existing physical misconceptions.

Having both taken and assigned problem sets for introductory physics, it doesn't surprise me to learn that students don't particularly enjoy them.

Yet many (most?) of them are seeking a career as, say, an engineer where solving problems will be their daily job! This phenomenon (students seeking a career in engineering because it pays well, without any clue about what you have to do to earn that money) is not a new one. It is much like the problem of students discovering after they get into medical school that they have to work with sick people. (Student: I want to be a pediatrician because I like children. Adviser: I hope you like sick children.)

If you just "check off" physics and don't learn certain parts of it really well, that first class in engineering is going to be one heck of a spectator sport for your friends.

It looks like agm's students got a taste of why this subject is relevant to their careers. It is also quite amazing how agm's students mirror mine, right down to the ones who are taking a harder class than they are required to take, and possibly hurting their acceptance GPA as a result.

"the problems with pre-existing physical misconceptions."

I've still seen a correlation in my students, when I had 100 in Astronomy lecture and a dozen in Physics lab, and subsequently in university Math courses (when the examples came from the sciences), and in secondary schools, between:

* Misconceptions as to what a professional SCIENTIST is and does;

* Misconceptions as to facts and theories of Science.

In the former, I've many students who only know abouit scientists what they see as Mad Scientists in TV, Film, videogames. Connected to this, I was appalled by the answers that I got when I gave homework questions about Peer Review. Many of my students think that the advertisers in Science Journals have an editorial role. Many students think that Network TV shows are peer reviewed, by cable shows are not. many students thought that Science Blogs are peer reviewed.

In the latter, confusion as to what constitutes a THEORY is seems connected with confusion as to the Scientific Method.

This was most acute when I taught the Theory of Evolution by Natural Selection, to those students whose parents believed that I was trying to get them to renounce their beliefs in God.

But it was real enough when I taught Newton's Universal Theory of Gravitation. My students were fascinated to learn that Newton probably died a virgin...

I haven't read the paper nominally under discussion. But I do know from experience that it's harder to teach Science unless and until you explain what a Scientist does, and how Science works as a social and cultural network.

it's talking about attitudes toward the science as a whole. Students are leaving introductory classes more likely to think of physics as rote memorization and drudgery than they were when they started.

Well, not necessarily. At a first scan, the authors don't appear to break out which questions the students rate lower after taking the classes; those may be the questions about how applicable physics is to their lives (e.g. "The subject of physics has little relation to what I experience in the real world") or about how well they think they can do physics (e.g. "If I get stuck on a physics problem, there is no chance I will figure it out on my own").

Also, I think it's worth noting that although the difference in scores are statistically significant, the actual amount isn't enormous; for the calculus students, it starts out as just 15% difference (approximately, from mean to mean). Yes, it gets lower, but wouldn't you expect a novice who now has some idea of how much they need to learn (e.g. calculus/post-class), to feel a little less... attached to the discipline? Wouldn't you hope they'd realize there's still work to do before they are as comfortable as experts themselves?

What would have countered that for me would have been a huge dose of actual, real world examples and results.

The book "Matter and Interactions" by Sherwood and Chabay is a step toward remedying that. There are still some frictionless examples, but they try to get more at the heart of the physics, and understand a lot of things in terms of microscopic phenomena. If they want a frictionless problem, it's likely to be a hockey puck on ice, not a car on a slope.

The Matter and Interactions curriculum does a good bit to shake up the intro class. Not only do they do more realistic problems (many of them through numerical modeling), but they present the basic concepts in ways that are different enough to make students who have had high school physics sit up and take notice. In the more traditional curriculum, students who had had a decent high school class could pretty much coast for the first six weeks or so, which caused all sorts of problems for us.

Of course, I say that not having taught the first term of M&I (I've done the second term, on electric and magnetic interactions, but not the first). It's conceivable that I might look at it differently in June.

I don't find this surprising at all. Students go into the class with a pretty good idea of what Real Physicists are like, and a lot of ambivalence about their own attitudes toward physics. After the class, they have more certainty about their own attitudes, and unsurprisingly most of them have found they don't really want to be physicists.

This precisely describes me -- I was one of those "maybe I'll major in physics" types in high school, but realized after a single college class that I actually kinda disliked physics -- so... what would you do differently to get people like me to like physics, lie about it? ("Hey, we don't really do experiments, we do computer simulations of the experiments, and they JUST FUCKING WORK with none of that tedious bullshit measuring nonsense.")

The job of intro courses isn't to make everyone like the subject, it's to give people enough information to know whether they'll like the subject, and based on this information, physics classes are succeeding, in that they are accurately telling people that they won't like physics.

Can you really be surprised about this? You crazy scientists believe in all sorts of wacky stuff, it's a miracle your heads haven't exploded from all the stoopid! Cats that are alive and dead at the same time? Loads of universes? Time slowing down and speeding up? Things getting heavier or lighter depending on how fast they go? Y'all are loony tunes!

(Just kidding...)

I think Mike Kozlowski has a very good point. The point of survey classes is not to get people to like a field, it's to expose students to a branch of knowledge that our society has finds very important for one reason or another, whether because students typically are better for it in some way, or because society benefits from exposing people to the ideas contained therein.

I didn't become a chemist, and in fact found freshman chemistry easy enough that I was tutoring declared chem majors. Only through friends and new activities (mmm, homebrew) did I later learn how exciting chemistry can be.

A couple things that would help, from my experience (HS physics + 2 semesters college phys w/ calc):
Bold is used here for highlighting so the main points can be quickly skimmed, rather than for emphasis

  • Explain everything - if you use epsilon-naught in EM, tell the students what the hell it is and where it comes from (my book just gave it a name with no explanation, and my teacher didn't know either). Magic numbers and physics don't quite go together - it's looks to much like fudging the data to the students, or like you're hiding/don't know/don't understand something. And don't just say "it's an empirically measured constant, like pi and e" - explain what it's a measurement of, and if it varies by some sort of condition (epsilon-naught depends on the material, for example, and along with another I've forgotten the symbol of, determines such things as refractive index - including some cases with negative refraction - and reflection).
  • My HS physics teacher had good method to make problems more interesting. He had a child that liked to watch Spongebob Squarepants - so we'd often get test questions where we had to figure out whether Spongebob died or not. "Spongebob has a rope with properties x, y, and z. He bungie jumps off a bridge of height h. Does he die or not? Show your work"
  • Explain why things can be taught in isolation, but ALSO show how they can be combined for real-world purposes. (explain, eg, that by considering something moving without encountering friction - like in space - and then the same thing on a surface with gravity & friction, we can see how gravity and the coefficient of friction affect an objects movement). And, if you want, demonstrate the utility of simplification for the purposes of the course - start adding in air resistance, surfaces with anisotropic coefficients of friction, etc - it'll make the point rather well about how all the individual parts can be combined AND why they probably don't want to do that for all of their problems.
  • Make sure conditions match the student's intuition and experience of reality - if you don't want friction, do it in space or on ice. If you want gravity without air resistance, do it on the moon. If something is not present in the problem, make sure it makes sense to the student why that is, rather than just hand-waving it away.
  • Pretty much everything agm said, with one additional point: tailor your examples to the interests, hobbies, and plans of the class. If possible, also time it with regard to local events.
    • Fair's coming to town next week? Perfect time to do the physics of rollercoasters in your problems!
    • Everyone in your class watches NASCAR?
      • Use internal combustion engines for pressure (how the cylinders move), thermodynamics (heat engine, keeping everything at the right temp, friction, etc).
      • Use the car radio system for EM (radio waves and the antenna, speakers for the relation between electricity and magnetism, as well as for solenoids.
      • Speakers and mufflers make a good example for the physics of sound as well)
      • AM vs FM radio for the difference between frequency and amplitude (as well slipping in a primer on some basic SIGINT material; this can even be extended to understanding how TV's can receive so many different things over the same wire/antenna [NTSC, PAL, etc], how cellphones work and the difference between 3G and CDMA, how wireless works and why it has different channels and versions, etc.).
  • DON'T go at the speed of the slowest student(s). Don't go too fast, either, but a lot of the students who can keep up or already know the stuff will suffer greatly, and there will probably be more people losing out if you try to go slow enough for everyone than if you go at a more reasonable pace. Keep pace with the majority, not the extremes - the students will compensate for the lower extremity on their own (the faster ones will probably not mind tutoring the slower ones, for one, and if you have something like SI*, there's even less reason for you to go that slow. *SI - Student Instruct[ors,ion]; a program at several of the colleges I've been two in Florida where students who've previously passed the course with good grades and understanding 'teach'/help the students in a supplemental session held in a room on campus at scheduled times each week.
  • Be prepared to go more in depth than the class is supposed to. At the least, have some resources available for the students who aren't satisfied with just the basics. I've suffered from this a great deal in my classes. I do much better if I can understand why or how something works or is the way it is, than if I'm only presented the derived results (eg - magnetism as a result of relativity + electricity makes more sense to me than magnetism magically having the appearance of doing work but not 'actually' doing it, as implied by the book and teacher). Undoubtedly many of the students won't care, but some bright and/or interested students will ne'er-the-less struggle more than they should if they're only exposed to the somewhat arbitrary-seeming explanations and results prevalent in an entry-level physics class. They may also get the wrong impression of physics, by causing it too seem to much like simple engineering (as opposed to complex engineering). Students who initially seem interested at the outset, but end up going into mathematics or another science probably suffer disproportionately from this problem - math and most of the other sciences are quicker and better (in general) at "getting past" or having a good explanation for the appearance of arbitrariness, and often provide easier access to the background, logic, and their unique methods/principles of investigation/thought than physics classes do. Well, chemistry aside, since it tends to introduce both too much and too little at the same time. This is also a good reason to either provide a method of skipping over the basic physics series (for those who know too much), or providing an advanced version (for those who to know too much).
  • Provide a sheet with the values of constants and at least some equations. This is the easiest way to get past the apparent importance of rote memorization in physics, by simply not making it an issue in the first place. The only people who, in the majority, know the values of the constants for their field either (a) teach a class involving them, or (b) use them so often they've memorized them by repetition. Likewise for the equations and integrals/derivatives. Think about it - what's more important: (1) How well the students can recall them, or (2) whether the students understand and know how to use them? Even better if you teach them how to figure it out from scratch - I'd much rather work with someone who can figure something out from scratch than someone who knows it all by memory. At the least, the former is more likely to figure out and/or spot something new and interesting (and probably won't suffer, professionally, as much if they later have brain damage incurring some loss of memory). Btw, that may also be why some of your students take so much longer than you expect - they're working out the derivation rather than relying on memory, and that takes longer.
  • Don't use labs to demonstrate something nor for practice at applying the concepts they've learned. It's a waste of time and resources - the former is best done by the instructor in front of the whole class during the lecture, and the latter is more easily done through assigned problems. Furthermore, labs do either or both of those dramatically reduce the interest of the students, especially if they're simply following instructions from a workbook and plugging in numbers. It can even build resentment over the labs, and increase the occurrence of cheating simply to get it over with - both of which reduce any utility the lab may have had. Use labs to build intuitive understanding and problem solving skills - If you want the students to get something from the lab, the three best ways are: (1) let them play around with the stuff (builds intuition and understanding), (2) make them figure something out how to do something, and then explain it (builds all three), and (3) Show them how to do something neat and then have them find a way to put it to use, or make it do something 'neater' (varies by what you do). It's fine to make them record some measurements if appropriate, but don't entangle the math with the labs. If you want to have them see that something held true for everything they did in the lab, use the measurements they took to either directly demonstrate it in a later class, or for homework/quizzes given the lecture following the lab. Otherwise, the students will focus more on getting the right answer on paper than they will on the lab itself.

I could probably think of some more, but that's a fair screed already. ;-) (tried using list tags, but it seems they're not accepted for comments - oh well)

..or rather, preview didn't show them so I could fix them...

As a graduating senior that took physics for pre-meds and then liked it so much I retook calc-based physics, I can say the following:

Physics for pre-meds was so much *better* than calc-based physics. PfPM opened with my professor spending a day just discussing how to think. The first day he drew a continuum on the board, from Math to Philosophy, and asked us to guess the percentage of each that comprised physics. He took a few answers, and then told us it was 90% philosophy - it was the art of thinking about the world, with math only being a tool to use at the end, to precisely articulate our thoughts. He spent a lot more time, both in class and on exams, teaching and asking complex concepts, but without using mathematics. There was a significant maths component (not far inferior to the calc based class), but that was not where the emphasis lay. I absolutely adored this class, and briefly flirted with becoming a physics major based on my absolute joy there. It inspired me to polish up my math skills significantly.

Then I took calc-based physics. The math was not significantly more difficult at all (given, I'd had calculus before I took either class). The key distinction was that the teacher ignored the philosophy, and the entire class became based on problem-solving, full stop. And there my love affair ended.

By James Stein (not verified) on 06 Mar 2009 #permalink