Physics Takes Practice

Doug Natelson talks about a recent presentation on education:

I recently heard a talk where a well reputed science educator (not naming names) argued that those of us teaching undergraduates need to adapt to the learning habits of "millennials". That is, these are a group of people who have literally grown up with google (a thought that makes me feel very old, since I went to grad school w/ Sergei Brin) - they are used to having knowledge (in the form of facts) at their fingertips in a fraction of a second.

I can certainly agree about the Google part-- having graded a bunch of preliminary lab reports yesterday, I was really struck by how many of the students opted to Google up a diagram of lab apparatus that was almost but not quite identical to ours, rather than making an accurate diagram for themselves. The more important point, though, is Doug's response to the expert's suggestions:

While appealing to students' learning modalities has its place, I contend that this concept simply will not work well in some introductory, foundational classes in the sciences, math, and engineering. Physical science (chemistry, physics) and math are inherently hierarchical. You simply cannot learn more advanced material without mastery of the underpinnings. Moreover, in the case of physics (with which I am most familiar), we're not just teaching facts (which can indeed be looked up easily on the internet); we're supposedly teaching analytical skills - how to think like a physicist; how to take a physical situation and translate it into math that enables us to solve for what we care about in terms of what we know. Getting good at this simply requires practice.

(See also this SMBC comic...)

I have the same reaction to a lot of talk about "millennial" learning styles and the like. At the end of the day, somebody who is going to leave my institution with a degree saying they have achieved some degree of mastery of a physics needs to be able to solve certain kinds of problems, and the only way to get that ability is through practice. Particularly in the introductory classes, there's just no way to avoid a certain amount of problem-solving drudgery-- you've got to work through a whole bunch of mass-suspended-by-wires sorts of problems in order to understand the central techniques.

Of course, problem-solving isn't everything, either. There's ample research showing that students who can solve standard homework and exam problems often have a remarkably poor grasp of the concepts behind those problems. This is why we now use tests like the Force Concept Inventory to help assess how we're doing, and that's the fundamental motivation behind most of the revised curricula that have gained some popularity in physics.

The problems-but-not-concepts thing shows up in lots of places, and I think it manifests in some odd ways. I'm pretty sure it's behind the phenomenon where upperclass physics majors can't answer questions when they're tutoring intro students, because they wildly overthink the problems to match whatever they've taken most recently. I also suspect this is part of the reason why many physics students and some full-blown physicists-- the folks at the Physics Stack Exchange-- bristle at requests for answers without math. It's not just that explanations without equations are less precise than explanations in words, it's also that some people aren't comfortable enough with the core concepts to do a good job with a non-mathematical explanation. There's more than a little truth to the cliche that you don't really understand something until you can explain it to your grandmother-- you need a really solid understanding before you can get around the math.

(Of course, typing this out feels more than a little hubristic, given that I'm in the middle of writing a chapter where I attempt to explain general relativity to my dog. And I will be the first to tell you that I can't hack the math of general relativity-- I almost immediately get lost in the notation. I've gone through a big stack of intro textbooks in order to get what feel I have for the subject, and you won't find me reading Misner, Thorne and Wheeler any time soon... I think I've got the idea, but I'm expecting to be savaged by my beta readers when I hit that stage.)

So, it's a complicated issue. I'm sure Doug knows this as well-- he does note a few times that he's being deliberately provocative. It's also one of the things that makes it so damnably difficult to compare teaching across disciplines-- you can't just say "Lecture bad; Discussion good," because there are contexts where lectures are just about unavoidable.

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I can certainly agree about the Google part-- having graded a bunch of preliminary lab reports yesterday, I was really struck by how many of the students opted to Google up a diagram of lab apparatus that was almost but not quite identical to ours, rather than making an accurate diagram for themselves.

Do you explain to them the objectives of the lab course?

I know I didn't figure it out until years later, working in an industrial lab and all of those lessons on detailed documentation turned out to be pivotal in a high-stakes investigation.

By D. C. Sessions (not verified) on 14 Feb 2011 #permalink

You might find Lawrie's "A Unified Grand Tour of Theoretical Physics" to be useful for sussing through the math of general relativity. I have the 1st edition, not the second, but I would assume that the 2nd edition also has a lovely (and brief) primer on differential geometry that leads into a nice (and also brief) introduction to the mathematics of general relativity.

D.C. Sessions: This justification just isn't as compelling to a 19 year old as you would hope. The fact is, thorough documentation is a lot of extra work in preparation for a scenario that will never, ever, ever happen to a student in an undergraduate laboratory. Even among students actually preparing for a career in industry, the attitude is generally "when I'm doing work worth documenting, I'll do so."

Baez and Bunn wrote:

"We promised to state Einstein's equation in plain English, but have not done so yet. Here it is:

Given a small ball of freely falling test particles initially at rest with respect to each other, the rate at which it begins to shrink is proportional to its volume times: the energy density at the center of the ball, plus the pressure in the x direction at that point, plus the pressure in the y direction, plus the pressure in the z direction."

http://math.ucr.edu/home/baez/einstein/einstein.html

I don't think the problem is that they haven't documented the apparatus sufficiently well, but rather that they overestimate the difficulty of producing a diagram in electronic format (as I require all labs to be handed in electronically). They're not comfortable using drawing programs to make diagrams, so instead they Google up something somebody else did. I also get lots of cell-phone photographs of the apparatus (some with absurd resolution making ridiculously large labs), and diagrams drawn by hand on paper then scanned in, and even diagrams drawn by hand on paper and then photographed with a cell phone.

This, by the way, is another reason why I am highly skeptical of claims of the innately "wired" nature of the current generation of students. They're just not that comfortable with computers outside of a narrow range of social networking contexts.

On the subject of documenting stuff, at a recent group meeting I attended the PI announced that he will start enforcing a policy of written documentation. There were sounds of disbelief from the undergrads around the table, but the PI provided the following justification. There are lab notebooks on the shelf dating back to the 1970s, when the current PI's now-retired predecessor was in his prime, and to which anyone can refer in order to look up details of those experiments. More recently, there has been a bunch of home-brew software, much of it written by a software pro, created to analyze data from the group's instruments. None of this software can be found, because there is no written record of where the files are stored.

That's why I take seriously the warnings about a digital dark age. Computer formats evolve noticeably on time scales of less than a decade, and many people don't realize the effort needed to migrate to updated formats. Paper ages too, but it's a much longer process, and as long as the physical medium is in good condition you can read it. Likewise, I have insisted on paper statements, so that if a question ever comes up I can look up the records from a few years back--when investments (including 401(k) and 403(b) retirement accounts) are involved, you basically have to keep records from when you bought it until several years after you sell it, just to be able to satisfy the IRS.

By Eric Lund (not verified) on 14 Feb 2011 #permalink

Chad said:

I don't think the problem is that they haven't documented the apparatus sufficiently well, but rather that they overestimate the difficulty of producing a diagram in electronic format (as I require all labs to be handed in electronically).

Quick and legitimately curious question: Have they ever been *taught* any kind of technical drawing, electronic or otherwise? Because I definitely wasn't, not in high school, not as an undergrad, and not even as a grad student. I can't fathom why it isn't a part of the usual graduate curriculum in physics, if not undergrad -- you can't very well have parts made for an experiment if the machine shop has no idea what you need.

Of course, plumbing the deep mysteries of AutoCAD is probably overkill for a freshman lab, but I think sometimes we just plain overestimate what our students come in knowing how to do. I'm not willing to let them off the hook for algebra, but...

Why does everyhting have to be entertainment? I read over and over, multiple places, that we need to tailor schools and colleges to the plugged-in youth with the attention span of a squirrel. If colorful and noisy stuff does not jump at them at few-second intervals, they lose interest. I know it's the truth that comes from high enrollment==>survival of departments, but it seems wrong on so many levels for schools to have to bend towards the most idiotic treats that students possess. If you have no interest in and no patience to learn physics, by all means go major in something else. If you have no patience or ambition for anything other than social networking, please don't waste your parents' money and leave college altogether.

By Applied Physics Prof (not verified) on 14 Feb 2011 #permalink

Quick and legitimately curious question: Have they ever been *taught* any kind of technical drawing, electronic or otherwise?

I'm not looking for AutoCAD drawings. I do figures at this level using the drawing tools in PowerPoint, and even that's overkill. Paint would be fine-- I'm looking for block diagrams and schematics, not 3-D perspective drawings to scale.

To give you an idea, the specific figure that half of my class Googled up is on this science fair web page. If you plan to be a scientist or an engineer, you shouldn't need formal instruction in how to make that figure using the drawing tools in Office.

Of course, the kicker here is that the diagram in question isn't the same as the apparatus we actually used. Meaning that they spent time Googling up a diagram that is significantly worse than what they could've made for themselves.

@MattPatt: The more relevant question is whether the students have been taught any kind of electronic drawing, technical or otherwise, and Chad's observations suggest that the answer is no.

If I had to produce such a figure, I'd probably use Adobe Illustrator (which I have on hand because I sometimes need to use it for cleaning up figures to use in publications). The PowerPoint drawing tools would work, too (I only use them when my intent is to build a slide by adding arrows and such), but not everybody knows that these tools exist. A hardcore LaTeX type (not that this description would apply to any of Chad's undergraduates) could probably produce such a figure within LaTeX's picture environment (I can't be sure, as Chad's link @9 is borked). There are lots of ways to do it, but as with any kind of content creation software you have to have it and know how to use it.

By Eric Lund (not verified) on 14 Feb 2011 #permalink

@Chad: Well, that's why I said that AutoCAD would be overkill for this. What I was trying to convey, although I apparently did it poorly, was that just because they may know how to type into Word doesn't mean they know anything about the (incredibly frustrating) drawing toolbar. Which was a roundabout way of agreeing with your earlier point; there's no evidence that "Millennial" really implies anything about the average computer skills of the group... although I guess I do have to disagree with you that it's necessarily reasonable to expect people to intuit how to use, say, the Office drawing tools with not even a link to a page of hints.

I do still have that issue with the "Millennials are l33t haxx0rs" idea, though -- where *are* they supposed to have learned all these skills from? Nobody ever really wants to answer that. It'd be like saying that baby boomers are all masters of CRT television repair because they grew up with at least one in the house.

I graduated high school in 1980. I have a b.s. in Psych which I earned in 1986. The most advanced math I'd had was algebra II my junior year in high school. I had no discipline, didn't do homework and had very low grades. After working in a med lab in the navy I rekindled my latent childhood interest in science. I went back to college and took math through calc at the turn of the century. It was wildly different. With graphing calculators much of the difficulty and tedium of math twenty years before was removed. It made it markedly easier to focus on concepts rather than being concerned with calculation(arithmatic) errors. Unfortunately my plans for an advanced degree did not work out. This still hurts a lot. But, recently I started to "relearn" math just for fun. My graphing calcs are shot and I'm too poor to buy a new one. What I'm finding out is that without those graphing calculators my depth of understanding has greatly increased. Those calculators provide a quick short cut to learning deep concepts...but the knowledge doesn't last and there are things I'm learning now, on my own, I just wasn't learning in those college classes with the calculator. I very, very, very honestly believe that there are times when aids can and should be used and times when focus should be given to learning the concept. Grade schoolers don't need to be using any sort of calculators. High schoolers and college lower class men don't need to be using graphing calculators as anything other than a means to check work. It is like the difference between reading a book and watching a movie.

By Mike Olson (not verified) on 14 Feb 2011 #permalink

I have to agree with Matt. As a boomer whose work didn't include publishing etc. I'd be up a creek without a paddle here -so I can understand how they might not know how to get a tool to draw with. In my case, I could write an OpenGL code to draw an amazing graphic, but wouldn't no how to get it into the document. I'm the same way with LaTex -I never got the LaTex version of hello world to work, so I'd be better off formatting equations by writing my own formatter from scratch. There are a lot of such secondary skills, that are taken for granted, that probably all need minicourses to insure that everyone knows the basics (and has the software working together etc.). Of course you want to teach Physics, not a bunch of secondary skills.

By Omega Centauri (not verified) on 14 Feb 2011 #permalink

You observe: There's ample research showing that students who can solve standard homework and exam problems often have a remarkably poor grasp of the concepts behind those problems.

Agreed. Is there any research showing that students who grasp the concepts in a course designed to teach to the FCI can also solve problems, and retain that ability after the semester break is over? Do they even retain the concepts?

@1 DC asks: Do you explain to them the objectives of the lab course?

Irrelevant. They don't believe anything we say.

They will, however, believe a senior who tells them ze got an easy "A" in some engineering class or a big raise as an intern because ze remembered how to write a report from a physics lab. Or tells them the opposite, that what you write doesn't affect your grade in any advanced physics or engineering lab class.

You might find out what your seniors think.

I think there is nothing wrong with embedding a photo of a drawing, and wonder why they don't embed a video of the experiment itself.

By CCPhysicist (not verified) on 14 Feb 2011 #permalink

I agree about the need for people to slogging through things, particularly in light of the hour I spent with my manager today.

If I hadn't slogged through Arfken during my education, I'd have never gotten an understanding of integral transforms as a general tool (there are several integral transforms used for various data manipulations in seismic data processing and interpretation). If he hadn't slogged through the same during the course of his education, he wouldn't be qualified to evaluate my training, or even to perform the tasks of several positions he's filled over the years.

Sometimes there is no substitute for blood, sweat, and tears.

There's absolutely no excuse whatsoever for these kids not knowing how to make a picture on a computer. I figured out how to make Word do what I wanted in sixth grade; yes, it's a pain in the butt, but it's literally so accessible a twelve-year-old who needs a report on Egypt with pretty pictures by the end of the weekend can figure it out.

The main problem is that we're not pushed to learn things on our own. We're essentially told "do the homework, take the tests, and you're guaranteed to pass", so that's all we ever do.

@MattPatt: I do still have that issue with the "Millennials are l33t haxx0rs" idea, though -- where *are* they supposed to have learned all these skills from? Nobody ever really wants to answer that. It'd be like saying that baby boomers are all masters of CRT television repair because they grew up with at least one in the house.

Could not have said it better myself. I have gotten torn a new one by my physics prof. for several things I should somehow just "know".

For example, he asked me why I wasn't drawing graphs (when we do it by hand in lab) to scale. I explained to him that my pre-cal teacher (the math class that was supposed to get me ready for physics) said that hand drawing graphs to scale is a waste of time since we are just looking for relationships, and when we put it in Excel or a graphing calculator it can be to scale. He tells me that is completely wrong and that I need to learn to graph.

Like Matt said, there are so many things chemistry profs. and physics profs. want us to know, but when the question is asked regarding where we are supposed to have learned this information nobody can answer it. Profs. need to get over the fact that many high school math and science teachers are poorly trained, and that unless they are going to lobby to get the way math is taught to high-school students changed, there are certain things that we will have to be taught. At the very least they could have a workshop on the basic skills like graphing, etc that we are supposed to "know" instead of ripping us apart.

By AmericanPsycho (not verified) on 18 Feb 2011 #permalink