Sunday, March 30, 2008

Physics Curriculum: Quantum Mechanics

My reply in Chad Orzel's blog, reproduced here in my own blog with additional comments, remarked that my "freshman" quantum mechanics class had served to develop (in me, at least) an intuitive view of how non-relativistic quantum mechanics works. [Actually, I'm pretty sure it had a similar effect on at least two other people in that class who went on to PhD degrees in theoretical physics and chemistry.] I am posting more about this based on a request in the comments. Sorry for the delay, but I did not have time to work on my initial draft at all this week. I'm still not sure it covers all of the key points, but it is a starting point for discussion.

I'll mention above the fold that one reason I think quantum mechanics is in more need of "reform" than instruction in classical mechanics is simply the fact that it is comparatively young. There are perfectly serviceable bridges in use that are over a hundred years old, designed with the same principles of static equilibrium we teach today. That physics, and how to communicate it to students, was already on pretty solid ground maybe a half century before quantum mechanics was discovered, let alone taught! In contrast, we are only a few generations removed from the very first graduate courses in quantum mechanics and it is unclear to me how much those have changed since, say, 1935. (I'd say we are only on the second generation of graduate level textbooks, if that.) Certainly most undergrad treatments of quantum mechanics use the quasi-historical approach, following the totally wrong ideas of Bohr so QM can be evolved from the familiar territory of classical mechanics.

There were many differences between my course and the normal curriculum at a typical university or college even today, more than a quarter century later.

This was not a "modern physics" class, the third semester of physics as codified in typical University Physics textbooks. Not even close. First, relativity had been dealt with a year earlier, in the mechanics course. It did not appear at all to distract anyone from the primary point of the course. Second, the only phenomenology was that of atomic physics. There was none of the "stamp collecting" of different topics from atomic, condensed matter, nuclear, or particle physics. It was a quantum mechanics class. Period. Hence my suggestion that Chad think about a class that uses his AMO research for examples without trying to teach three or four PhD subject areas with only a few weeks devoted to each. Teach one thing, and teach it well.

The textbook was the 4th book in the 5-part Berkeley Physics Course. Most students in the class had come through that sequence, which assumed that you had completed calculus 1, 2, and 3 by the third quarter of your freshman year and were currently enrolled in a differential equation course when starting mechanics. Others were 3rd year students who had wandered in from the regular sequence taught from the original edition of Halliday and Resnick. The prerequisite course, from the "waves" book (still possibly the best book on the topic, period), meant it was assumed that everyone could solve the basic PDE for waves and could do the vector integrals encountered in E&M.

The instructor was a professor of physics with two PhD degrees, one in physics and the other in philosophy. He taught some courses on the philosophy of science in addition to courses in physics. Some years later I came to realize that important parts of his approach to the course followed the Feynman Lectures (which might have been the text for this sequence in earlier years) as well as being colored by his own research interest in conscious observation vis-a-vis objective reality (EPR, etc) from the philosophy side of his career.

A key element in the course was to break down our existing physical intuition. This was the part that seemed heavily influenced by Feynman's lectures on quantum mechanics, although it also built on what we could do with electromagnetic waves. The basic point he made was that everything we knew was wrong. We knew how to do orbits with the coulomb force. We knew how an accelerated particle would produce dipole radiation. We knew how to calculate the energy carried off, and hence we could prove that hydrogen atoms do not exist. Oops. Ditto for several other things, at various points in the course. The philosophical point was not just that our knowledge of mechanics was incomplete, it was that it was wrong. Fundamentally wrong. It could not be trusted.

From the other direction, if you start with classical non-relativistic quantum mechanics, your results can be trusted. You can derive classical mechanics from quantum mechanics, but not the other way around. (That is, Bohr was totally wrong in his approach.) Quantum mechanics tells you when classical mechanics can be trusted, and when it can't. There was no formal emphasis on Dirac's proof of the connection, but this was no surprise to me when I encountered it. The point of emphasis was quite practical: the questions that quantum mechanics, and only quantum mechanics, can get right.

But it could have been something more subtle that made the class work for me. There was none of the "quantum weirdness" that was so common at the time and still appears in textbooks that start from the Bohr model. The only weird effects were ones like Feynman's bullets fired at slits in armor on a battleship, the ones that modern EPR experiments have documented repeatedly. There was no emphasis on totally wrong ideas like the need for a quantum jump in the Bohr model. We had overlap integrals between wave functions that made it quite clear that transitions were entirely local.

The one thing it did not have (IIRC) was much in the way of linear algebra built on photon polarization as a model example, the starting point for my graduate course, where the fact that QM is actually an algebra acquired greater relevance. I have, however, seen this starting point used with great success in a senior QM course taught at another university I have been around and would recommend it.

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Wednesday, March 26, 2008

Much Better ISS Photo

Learn from your mistakes! This photo was taken tonight as the International Space Station went overhead. Two other pictures and a detail frame (explaining that the dashed effect at the start of the track is an artifact of manually releasing the shutter) are below the fold. Click the picture to see a larger version.

All photos were taken with speed set to ISO 200 (twilight sky is no longer so overexposed) and manual exposure for 10 seconds. The picture above was with the lens at 18 mm and f3.5 for two reasons: to wide the view to include the tree, and because it was really moving fast as it went overhead. Other than reducing the size by a factor of three, only modest Photoshop adjustments were needed to darken the sky.

An earlier picture, shown below, was made with the lens zoomed to 70 mm and f4.5.

The frame below, cropped from the original picture and shown without resizing, shows a detail of the dashed part of the track.

You can clearly see the spiral motion as the camera undergoes damped simple harmonic motion after I pressed the shutter and let go of the camera. Final lesson is that I need to plan better and dig out the remote shutter release to get rid of that junk.

A later picture, shot with 18mm like the one at the top, shows the ISS heading for the horizon and the lovely urban landscape of power and cable TV wires.

Other technical details: There was no need to work from the raw files when processing these pictures. Other than resizing, the only thing I did was use the manual levels control in Photoshop to darken the sky and improve contrast. Moving it to about 0.70, which was near the bottom of the lowest histogram peak, gave what you see here. (Using autolevels would brighten the sky, making it look like daylight, as shown in one of the modifications to yesterday's single photograph.)

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Tuesday, March 25, 2008

Crappy Space Station Photo

I now know I can do better, as this was not exactly thought out, but I figured I would post it anyway just to show that it can be done ... and to record the always awesome experience of seeing the space station and the shuttle go overhead. The photo was made on the spur of the moment. Technical nonsense is all below the fold. Click on the image to see all of it.

The squiggly lines are a sort-of-double exposure of the Space Station flying over our house tonight. It is really one very long exposure, but there are two tracks (and two trees and two power lines) because I moved the camera during the exposure.

Given the lighting conditions (there was a sodium vapor street light on the power pole that is in the lower left corner of the frame), this is actually quite amazing. This picture resulted from some significant tweaks of the Nikon raw image and has been resized by a factor of 4 from the original to save on disk space and bandwidth and to smear out the artifacts of a long exposure at low light levels.

We also saw the Space Shuttle, which was about 20 seconds behind, but did not even try to get a picture since (a) it was quite a bit dimmer and (b) I didn't think this one had turned out.

The original was a real hack photo, but I figured I'd post the mistakes in case anyone wants to learn from them. It was taken with a Nikon D70 and a 70 mm lens with aperture priority !! forcing it wide open at 4.5. As stated above, we were just out in the street around the corner from our house where we had a good view of the track, which was only 20-something degrees above the horizon. Unfortunately, the view through a gap in the trees was over a street light. Fortunately, the ISS is pretty bright and software can perform miracles.

Mistake 1: I completely forgot to bump up the ISO from 400. Not sure if that made it worse or better, given the original camera image below. I actually don't think I would change it to a higher setting unless I had a better sky (like we had for the lunar eclipse). Mistake 2: Using aperture priority. Little did I know that the exposure time would go to infinity in this case! The jiggles are because I kept my hand on it, figuring it would need to be fired again every few seconds. Nope. Stayed open. I moved the camera after 5 seconds or so (guessing, because there was nothing to see through the SLR), and finally realized that the only way to close the shutter would be to turn the camera off. Next time I will use the manual setting and find the remote so I can leave the stupid thing alone.

What worked: Post processing. The image above is the result of starting from the raw file (the NEF raw data from the digital sensors) and pushing the color temperature way down (to about 2300) and tweaking the tint about 20%, using the color of the tree leaves as a clue. (You can see a lot more color detail, and noise, in the 6 Mbyte version.) I had first tried the tungsten presets, but that was not enough to kill off the effect of the sodium vapor light illuminating the tree (and all the other ones polluting the city sky). This is quite an improvement over what the camera showed me in the preview window and dumped into the basic jpeg file:

Yeah, that is really horrible. Nothing but sodium yellow and a bunch of lines. Suprisingly, one can do almost as good as the raw file edit just by hitting the Auto Levels adjustment in Photoshop. That gave the result below, which really shows the doubly-exposed tree rather well but leaves the power line yellow from the street light and still shows the track of the space station.

Both of these pictures are tiny (reduced by a factor of 8 from the original) since they don't actually contain any additional information. They do, however, show that what looked like a dark sky isn't even close to being dark!

Closing comment.
When I say "always awesome", I mean just as awesome as when I saw Echo go overhead. When I called my parents to tell them that there were some really good ISS viewing opportunities this week, my Dad said "The first satellite I ever saw was Echo". Me too. I was standing right next to him at the time.

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Monday, March 24, 2008

The Other Cold Fusion's 19 Anniversary

Nineteen years ago today, an article appeared in the New York Times reporting on a press conference in Utah. That press conference, and the excited hyperbolic claims of Pons and Fleischmann in the local media that they would have a commercial hot water heater available for testing within six months, proved to be the scientific highlight of their research ... since later work by that pair got to the point where they did not even cite their initial paper as the genesis of the ideas they were working on.

In many ways the self-politicization of their work (choosing to ignore an invited talk at a national American Physical Society meeting in Baltimore despite the fact that they were less than an hour away in Washington DC with plenty of time to drive there after their Congressional testimony asking for funding) hurt the study of low energy nuclear reactions that had been taking place for years with DOE funding. Some of the controversy even obscured the normal way that new discoveries get announced. But nothing can excuse their ignorance of experimental nuclear physics techniques.

For example, extremely low energy nuclear fusion reactions, termed "cold fusion" by Steve Jones, are well documented in reproducible experiments that demonstrated scientific breakeven. There is no question that the physical effect is real and offers interesting atomic/nuclear physics effects to study. It got relatively little attention from both theoretical and experimental physicists, however, because it had also been demonstrated that the process was highly unlikely to achieve engineering breakeven (the efficient production of energy such that a power plant could be run profitably).

For another example, they were routinely attacked for doing "physics by press conference", which was nonsense. What they did, which was hold a press conference after a paper had been accepted for publication, was not that unusual even at that time. It was, however, unusual that the paper involved had not yet gone to press and would (according to documentation published by Frank Close) be changed between the press conference and actual publication. Most press conferences, such as the one held a year or so earlier concerning high temperature superconductivity or ones that are routine today for major discoveries in physics or biology, take place after the paper is in final form and actually in press. IMHO, most of those comments were actually directed at two related circumstances: the paper itself did not contain enough information to replicate its specific results (particularly the claim they observed neutrons) or to document its claim of "ignition", and the failure to acknowledge the collaboration with Steve Jones, who had documented his own ideas regarding fusion in a chemical environment several years earlier and shared them with the group at Utah. The highlight, however, remains that they didn't even notice that they had left the name of a co-author off of the paper itself!

The first of these was the most damning from the standpoint of publishing your experimental work. When the discovery of YBCO materials was first reported (again, in the New York Times) before the article in Physical Review Letters had arrived in anyone's mailbox (actually before the issue had even gone from printing press to mailroom), rumors of the recipe allowed many research groups to replicate the experiment. Once the paper appeared, it proved elementary to carry out exactly the same steps given in the paper and get the results that had been reported. In contrast, even Pons and Fleischmann seemed unable to get their own results by repeating their own experiment. Apologists would argue that it was more subtle than they had thought, but that is not an excuse for not saying exactly what they did in each experiment.

One other difference also stands out: Two decades later the YBCO-type materials can be produced in bulk and are finding application despite challenges posed by their brittle nature. Almost two decades later, scaling the Pons and Fleishmann experiment up to "water heater" scale has proved far more difficult, perhaps even impossible. The people still working in the area are following somewhat different paths without any progress towards the commercial product that was promised before the end of 1989. Will we have it on the 20th anniversary? Don't hold your breath.

Finally got the time to update this and pull it out of the Draft folder, but it still needs one addition.

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Sunday, March 23, 2008

Not so Light Reading

Two recent articles of some significance in The New Yorker have come with web-only addenda that are worth linking here.

The first, in the March 17 issue, concerned an album of daily-life photos from the Auschwitz concentration camp.
(That is the issue with the priceless cover of Hilary and Obama in bed, fighting to pick up the red phone. I've linked to the cover art thumbnail on their web site, but I doubt the link will last long.) The article itself is not available on line, but selections from the album are there with enough commentary that you can get the gist of the story. These are really a must see. They are totally unique (including the only pictures of Mengele at the camp) and greatly expand our historical knowledge of how the killers lived.

The other article, "Exposure" from the March 24 issue, is available on-line. It gives the back story of the woman who was in the most sensational photographs taken at Abu Graib, and provides her testimony about what happened there and perspective on the photos. The related web material includes both photos and videos.

This article and web material add new information to what has already appeared in a series of three articles about the prison and one about the investigation by Seymour Hersh. The one thing it does not shed any light on, at least as far as I could tell, was on the questions raised in the second article about who issued illegal orders to a Navy dog handler, William Kimbro. After all, if you can be prosecuted for following illegal orders or ignoring a legal order, the fact that Kimbro was praised rather than prosecuted for ignoring an order begs the question of why no officer (intelligence or otherwise) has been charged with issuing it. Like I said, not so light reading. We may need to wait for a regime that actually supports the troops before we find out.

The videos are part of a documentary, Standard Operating Procedure, that has a projected release date in April (Tribeca Film Festival) and late May (in Germany). A trailer is on the Sony Pictures Classics web site.

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Welcome Spring

Should have posted these on Thursday ...

The first sign of spring around our house are these dwarf iris by the front door.

The real indicator, however, is when the violets start to bloom in the lawn.

No one planted these, as far as we know. They have always just been in the lawn as "volunteers", and fortunately no one ever used a broadleaf herbicide to kill off winter weeds.

You have to look to see them, since they are small and dark (this is an extreme closeup), but I see them every day in the spring when I head out to my car. They last for weeks.

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Happy Easter!

You can't have Easter without the Peeps ...

Humorous Pictures

... but these Peeps need forgiveness more than most.

(See more time wasting nonsense at ICanHasCheezburger.)

There is no photo credit given, but the picture was probably among the submissions to the contest at the Washington Post (more about that below the fold) I saw featured on CBS Sunday Morning today, which also picked up the Peace Symbol story.

An old article in the Washington Post article (from 2007) includes a link to their Peep Show of last year's entrants. The article about the 2008 contest I tracked down might require registration, but it seems to link OK for me without logging in. It also has a photo gallery.

I should single out picture #18 for my brother. It comes from his all time favorite fun movie.

The story on CBS Sunday Morning says they picked the winner because of the detail work on the coffin of King Peep-ankh-amun, but I prefer #2 (Andy Warhol style Peep Art). Regular users of Teh Intarnets and what comes down its tubes from YouTube will recognize #5 (the Thriller video from Cebu in the Phillipines. Current events are reflected in #8, whose reenactment of Sen. Craig in Minneapolis is almost better than the one Keith Olberman did, while picture #16 was allegedly taken in 1932. Other pop culture icons (Spongebob at #26, Star Trek last at #37) also make an appearance.

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Saturday, March 22, 2008

Anti-Hydrogen Atoms

There is antimatter, and then there is antimatter. The former (individual antiparticles like positrons) has been known since early in the last century and used in huge quantities in accelerators for decades. The latter (actual atoms made of anti-protons and anti-electrons) is a bigger challenge because matter is neutral and cannot be manipulated the way individual anti-particles can be.

The subject of anti-matter must be one of the most common side-questions that come up in my physics class, given its prevalence in Star Trek. (That would be one of the curriculum issues in a previous comment and a planned followup, since modern physics is not on the list of key topics for pre-engineering physics.) A new publication reports a major advance related to anti-atom production.

A new article in Physical Review Letters by the research group at Harvard led by Gerald Gabrielse reports on improvements in their ability to trap anti-hydrogen atoms. The best overview might be on the web page of the ATRAP collaboration, although their most recent "breaking news" is 6 years old.

Any progress by this group interests me because it is a field of research where the project could very well take an entire career. I first heard a talk by Gabrielse at least 20 years ago. The ultimate objective, to make anti-hydrogren atoms and store them at rest in the lab so you can study the atomic levels in detail, is a heroic one. His work is interesting because it uses AMO techniques (the sort of thing Chad Orzel does to study normal atoms) in pursuit of a particle physics goal: to find out just how good the symmetry of "Time reversal invariance" is. Does it extend as far as the levels (and the relativistic effect known as the Lamb shift) of an atom made entirely of anti-particles.

AMO = atomic, molecular, optics

Along the way, Gabrielse worked with Hans Dehmelt, who shared in the Nobel Prize for key developments in trapping ions (charged particles) that might not have been possible if he had been captured in the Battle of Stalingrad in WW II. I think there is little doubt that Gabrielse deserves the same prize if his research program succeeds ... although he has competition.

As you might guess, the challenge in working with antimatter is that everything you use in the lab is made up of matter. If any matter, include any gas that leaks into your equipment, touches what you are studying, it is gone in a flash of energy. That makes Chad's professional interest in the esoterica of quiet and noisy vacuum pumps even more important than when working with ordinary matter. Everything, including slowing down and probing the antimatter, has to be done with photons (lasers) and electromagnetic fields. This is a lot harder when the thing you want to work with is not electrically charged.

One related material is positronium, which is an "atom" made up of an electron and an anti-electron. It lives a short life because the antimatter is never far away from the matter, but it has provided lots of insight into antimatter and time reversal invariance. We know the properties of these particles to an astounding precision.

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Thursday, March 20, 2008

Physics Curriculum Comment

The bulk of this was posted as a comment in the thread "Uncomfortable Questions: Physics Curriculum" in Uncertain Principles. I'll try to define the context of my remarks, but you might need to look at that to get all of it.

By way of background, my students do not have the 1240+ SAT average they get at Union College. Just looking at my students, the half that do have either SAT or ACT scores (a CC only requires a HS degree and a pulse for admission) are in the 1100 territory. The half that don't are probably not too far below that, but the spread is huge (like from 800 to over 1400). A typical FCI score is pathetic, mainly because the majority have not had any HS physics and half of the rest had a bad class. Foreign HS grads are the main exception to this rule.

Nonetheless, I agree 100% with Chad's main thesis that "My general suggestion regarding reform of introductory physics classes is that the goal should be to make them look less like high school physics." I do that with problem solving and pushing the math envelope whenever possible, usually in the second semester, but also get outside the actual text topics to connect to actual real-world engineering and physics problems.

My comments in his blog, repeated below, were not in any logical order nor do they follow his article in any particular fashion.

Regarding "Only about three percent of students who take introductory physics ever take another class in the subject. That's pretty dismal."

1) Compare the number of BS engineering degrees to the number of BS physics degrees and your 3% number is easy to understand, particularly when you consider the number of electives in a typical engineering program [zero].

2) One way to increase that number is to offer a "concentration" (if not a really minor minor) in physics that only requires a third course in modern physics. This can be popular with EE and computer engineers like you have, also materials science. Heck, *you* could tailor it to modern physics with an emphasis on (a) quantum mechanics, (b) lasers and AMO with a teaser about optical computing, (c) enough nuclear physics to be educated about the difference between a bomb and a reactor, (d) enough relativity to discuss astro topics and/or QED. You ought to get at least one extra major a year out of part b alone.

Regarding this posted comment In particular, it always amazes me how bad quantum mechanics classes are. The math is far easier than in E&M or analytical mechanics, yet students feel as though they are underwater the entire semester.

3) I agree 100% with #1 about QM. I evolved from a math undergrad to a physics grad student because I got hooked by a great freshman QM class that made the subject intuitive (to me, at least). If there is an area that needs reform, that is it. Why should the first "majors" class be intermediate classical mechanics?

Regarding "Most of the students in our introductory classes come in thinking that they're going to be engineering majors, and the just-like-high-school approach doesn't encourage them to change their minds."

In addition to my second remark up above ...

4) I am under no illusion that I am teaching mostly engineers at my CC, and I pitch the class that way, yet I have managed to produce some physics majors ... one of whom is applying to grad school this year. Could it have helped that I don't pretend that I am teaching "real" physics and frequently allude to the things you could work on when you do, as well as the next level problems my engineers will have to solve?

5) One of the other things that hooked me into physics was the nearly miraculous agreement between the solution of a system of coupled DEs for a double pendulum and a demo of same. This was also in the freshman sequence I took (out of the old Berkeley course that I saw used recently at MIT). The key there was a bit of non-trivial math explaining reality (really well) rather than a qualitative demo or 'easy' math problems.

5a) If you want to wake up your class, start out with F=ma and do an un-driven damped oscillator in the second week? Using a complex solution to the DE? Then do the pendulum out to the cubic term in the series? Then do the coupled system of two oscillators, with each of these tested by experiment.

Added comment: Part of the rationale here is to kick them out of their comfort zone. Just as half of the valedictorians at CalTech are suddenly below average, kids at Union should get a sense that more is expected of them than was needed to coast through high school. My challenge is the exact opposite. My students have an inferiority complex and need to realize that they can handle something they don't even dare teach to the university students they will compete with next year. This requires some coaching.

Regarding "while we're hitting them with block-on-an-inclined-plane problems that they've seen before."

Most of mine have not seen it before. Some insist they haven't seen it even after we did it in the lab! That is probably a universal problem.

6) Part of every class coasts through the first part of the 1st semester, but my survival fraction would fall significantly (maybe by a third or more) if we did not spend time on kinematics and problem solving. [My answers to the three questions I posted are quite different from yours, I am sure.] I cannot start with challenging modern concepts when most of they are still being challenged by word problems that generate two equations in two unknowns.

Regarding "might help to show them that physics is more than just memorizing lists of equations."

7) My response to the view that physics is about memorizing equations is to note that it should be about problem solving with a handful of equations. No one should give the "range" formula in a freshman textbook or use the elastic scattering equations. The students will only work from first principles if you do. And it does not hurt to give exam problems that have a symbol or three in the answer rather than just a number from a calculator just to be sure they can solve an equation without graphing it.

Added comment: I fight the "equation grabbing" approach every step of the way. Gauss' Law is not 7 equations for 7 different geometries, it is one equation plus your problem solving skills. Here is one place where I go way out of my way to make it impossible to equation grab to the final answer. One way is to ask for the first part of the solution, not the answer.

Further, since the biggest complaint about a typical sophomore entering engineering is that they can't solve a new problem or do free-body diagrams, I sometimes double up on that by giving them a nasty problem where the only thing I want is the correct free-body diagram. It never hurts to think.

Full disclosure: I knew guys in grad school who only got through the comprehensive exam by memorizing the solution to as many possible problems as they could. This approach is not limited to undergrad engineering majors.

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Now Everyone Knows

For many years I thought I was one of only a few people who knew the "peace symbol" was assembled from the semaphore signals for N and D (nuclear disarmament). (OK, when Googling up a link for it, I see that Wikipedia, in its infinite wisdom, also knew this. Is there anything that is not in Wikipedia? [see note at end])

Now, thanks to a news story about the 50th Anniversary of its use in the British anti-nuclear movement, everyone knows (or could know this).

That might even include the maroons who still argue it is a broken cross or some sort of satanic symbol. (They can be excused if they can't count high enough to know the different between an upside-down pentangle and the peace symbol.)

When I could not remember the Ramanujan number (1729) and Google turned found it in Wikipedia with the entire back story, I knew the thing was pretty powerful. Heck, it even has the generalization known as the Taxicab number. An aside: I don't like calling it the Hardy-Ramanujan number because Hardy had no idea it was special. He just took a cab. IMHO, someone is giving the British fellow too much credit.

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Wednesday, March 19, 2008

Who says bloggers don't get tenure?

Last year it was Chad Orzel over at Uncertain Principles, who got an e-mail to that effect in mid February.

This year it is Profgrrrrl, who got notified in mid March (link will not stay available for long).

I find it interesting that it takes only a month longer at a large research university than it does at a small liberal arts college, and that the former appears to have used an expensive actual letter rather than e-mail. Also interesting is the detail that Chad's college waits and sends a Really Nice Letter in the summer, which shows a really personal touch, and offers to split the cost of academic robes. Again, when there are only 200 faculty, you must have to go out of your way to get a goodly number of "spear carriers" for when the fat lady sings compared to the situation at a megaversity.

Random closing thoughts: Chad's liberal arts college has about as many students (for four years) as my high school had (for three years) and half as many students as my dorm had! However, my dorm also housed the "residential" college I was in, so it is clear that my alma mater did a good job simulating many features of that sort of education within an otherwise huge and anonymous organization.

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Links and News

Topics: carbon in another solar system, students, academic basketball, Arthur C Clarke, strategic victory in Iraq.

Cool news that methane (meaning carbon) has been detected on an extra-solar planet. There are quite a few reports (BBC, Discovery News, National Geographic) based on the same news release. Astroprof blogged about Arthur C. Clarke (see below the fold) today, so maybe s/he will get on it tomorrow. [Update: Nope, but Chad did.]

I was entertained by Chad's comments about what student habits irritate him the most. It is great to see that students at an expensive liberal arts college are not that different from those at a very cheap community college. In fact, I think ours are better. I did have a student miss an advising appointment today, but I regularly get e-mail replies to confirm a time or to warn about an absence (and I don't take attendance or penalize for absences, so I could actually care less, but they care, which is nice). I can see that I really do need to assemble my blog about lab teaching, after his remarks about bogus reports. [I tell them that I will mark off for lame explanations like "the experiment failed because the water was too wet" or "I can't find my mistake in a calculation I was supposed to do before I left the lab".]

Basketball is here, so it is time for the folks who think college sports should be played by college students to point out the obvious disconnect

Thanks to Sherman Dorn for having a link to the second one. Full disclosure: my favorite college player graduated directly to the NBA, did not wear gown, did not get degree. My second favorite is a physician running an entire building at Stanford med. Both were on the same team, one backing up the other.

Arthur C. Clarke died. Chad Orzel has a nice comment with a link to the NYTimes Obit. There is also a good obit over at the BBC, which also has a page devoted to some of his predictions. I was never a Sci Fi fan, so I only really admired him for the idea of geostationary communications satellites (but learned for the first time from the NYTimes that his failure to patent the idea was not out of altruism, having heard incorrect versions of the story for years) and for 2001: A Space Odyssey.

I'll never forget the trip with my dad to Detroit's Fox theater to see 2001 on a huge Cinerama screen during its original release. I loved the intellectual challenge of "film" that told a story without any explanation of what was going on, but my dad was baffled by the imagery of the rapid aging and rebirth of a new man during the last half hour or so. Of course, that film was as much Kubrick as Clarke. (And the most impressive thing about Kubrick was that he could work with such different subjects and styles and coauthors, never doing anything like the same thing twice.)

I like the way the BBC picked up on the news that President Bush declared a strategic victory in Iraq today. That would be two victories in the same war, something no other president has managed. And since the war continues with a quiet strategic withdrawal (we are de-surging as I write, no one would dare call it a pull out), he might even have a chance to win it a third time when the fighting stops.

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Monday, March 17, 2008

Monday After Break Question

I think I'll see if I can start something here.

How many e-mails did you get from students the day after break ends saying they could not make it to class due to transportation issues?

My answer is below the fold. Put your answer in the comments, or blog your favorite.


One car broke down, and the other was stuck in the Philadelphia airport.

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Friday, March 14, 2008

Random Thoughts on a Friday

Thanks to the comment section over at Dr. Crazy's place, I stumbled on a real classic via a new blogger from the Great White North. (Maybe you have to be of Scandinavian ancestry to react immediately to the ambiguous anger of a title like "We have mixed feelings about Sven Sundgaard", but so it goes.)

The classic is Garfield minus Garfield. I need to update the blogroll to include it and a few others, like the WW I soldier's blog (see below). "Garfield without Garfield" is about as surreal as it gets. Hysterical.

In addition, the 12 March posting by Pacifist Viking about the media also hit a nerve, more so about today's news coverage than the multi-day coverage of the departure of the governor of NY discussed in that blog. Consider the following:

  • A political discussion on "Hardball" where the host interrupted a guest talking about the issues (little things like the war and the economy) because he wanted to discuss the "horse race". Memo to Chris: That kind of thinking (if we are charitable enough to call it that) by the media is what resulted in a majority of Americans believing that Iraq had something to do with 9/11.
  • Hours of discussion about what the preacher at Obama's church had to say on topics as wide ranging as the US government infecting blacks with syphilis, ignoring genocide in Africa, and not acting on intercepts that implied Japan was going to start a war on 12/7, with most of the focus on an allegedly controversial statement about 9/11 that can be found in the 9/11 Commission report. [Side comment: My very Republican father often repeated the claim about Pearl Harbor that this allegedly radical left preacher made in video shown on Fox.]
  • Almost nothing at all about a run on Bear Stearns, a US investment bank that makes a bank run in the UK last year look minor by comparison.
Little wonder that "W" was out jawboning the economy today, saying it is just doing fine, but the sidebar on a BBC story tells a different version: Credit Agricole loses 5 G$, HSBC loses 17 G$, Citigroup loses 18 G$, and Merril Lynch loses 14 G$. Fortunately, reports are that those banks are still making money, but Bear Stearns did not have a problem either until rumors of a "liquidity crisis" (a fancy term for a run on the bank) created one. This is more important that what any preacher says, whether he is an Obama supporter or a McCain supporter.

Finally, the real time (albeit delayed by 90 years) blog of Harry Lamin, a World War I soldier has been fascinating to follow. As fame of it has spread through media stories, particularly on its first anniversary earlier this year, more has been added by others interested in the story. The latest is a set of maps (apparently based off of Google Earth) that show the terrain along with the location of his unit as we follow his letters.

I am particularly fascinated by this because the soldier involved entered service only 6 months or so before my grandfather did. He only told part of the story, as does Harry, whether in his letters, his diary, or the stories he told me. Its great to see another view of that conflict.

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Talk Like a Physicist Day

I think it was rather clever of us to hijack Pi Day from the mathematicians, and use it to create Talk Like a Physicist Day. The idea must have come from theorists or mathematical physicists, using the excuse of Einstein's birthday to March 14th. Wouldn't an experimental physicist pick another number or hero to worship? No one ever measured pi, and I have yet to see a goniometer or spectrometer with its angle measurement in radians.

But as a theorist currently teaching AC circuits, I'd offer terms like "impedance mismatch" or, in particular, the phrase "e-to-the-i-omega-t" as a first approximation to what belongs on such a list.

One thing that seems to set us apart is the use of equations (including greek symbols) in common speech. I've noticed that our math faculty don't talk greek very much beyond theta (or sometimes xi, eta, and zeta) and will apparently accept 3.0e- (or even 3.0e^{-3} in one recent case) as if it were correct scientific notation.

Physicists will also mutter "curl of the flow field" when discussing water going down a drain, or decide to buy gasoline before the tank is empty because the derivative of the per gallon price is positive.

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Star Wars or Top Gun Fan?

TCM is showing The Bridges at Toko Ri tomorrow (Saturday, 15 March) at 6pm and, if you miss it then, again in April and May. This classic Korean War air-combat movie (set on an aircraft carrier) has a lot going for it, not the least of which is the similarity between the bombing runs against the bridge and the final attack in Star Wars.

But before giving several reasons for watching this film, I'll also mention that TCM is showing Gaslight tonight. This is a thriller made by George Cukor, starring Ingrid Bergman and Joseph Cotten with Charles Boyer heading the bill as the bad guy. (This is a good role for an aging leading man like Boyer, but a better one for Cotten.) For Cotten, this 1944 film is bracketed by two of his classics with Orson Welles: Citzen Kane in 1941 and The Third Man in 1949. Curiously, when I mentioned him to my Mom, she said she was a huge fan of his and had spotted him in Hollywood circa 1950. Must be genetic.

Back to The Bridges at Toko Ri. The main reason a Star Wars fan should see it is to compare the scenes of jets attacking the bridge with the attack sequence on the Star Destroyer. Top Gun fans should watch it for the (real) carrier action scenes from 30 years earlier.

The IMDB trivia page credits two other films (Dam Busters and 633 Squadron) as resembling the final attack on the Star Destroyer. However, a long time ago in a state far away, I heard promo comments about Star Wars that said film from "Toko Ri" had been used as filler while the FX sequence was still in production. Having seen all of these movies, the reference to Dam Busters is a joke since the bombing run is over a wide lake with AA fire only from the dam itself. 633 Squadron makes more sense (attack runs up a fjord protected by AA fire), but lacks the "roll in" attack profile and intensity of the jet fighter-bomber run in Toko Ri.

Watch it, and see if you agree. The whole style of the attack, one plane at a time taking its shot at running the gauntlet to attack the target, is similar.

This film is also notable for several other things. Based on a novel by James Michener, the film captures the futility of the Korean War and the barely suppressed anger of reservists (such as the star of the film) who were called up from their civilian careers despite having served in World War II. (I think I mentioned this in a comment on one of the blogs I read. The father of an old HS girlfriend saw active duty in WW II, went to college, graduated, then went to Korea. He was not happy, although his was a case where he had experience that was needed immediately, because there was not time to train new draftees. My father was similarly resentful, mainly because what he did during Korea could have been done by a newly trained draftee rather than someone who had just graduated from college. This is the same issue that the movie "Stop Loss" will address in today's context with no draft to fill gaps in the military.)

The movie also has first-rate real footage of carrier combat operations in the jet era, having been filmed with the full cooperation of the US Navy. It is instructive to compare deck operations in 1954 with those from 1986 shown in Top Gun. It is all a bit rougher during the Korean era because the carriers had been designed for prop planes during WW II, not the early jet fighters used in Korea. Although it is a movie, much of the action footage is as real as any documentary.

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Thursday, March 13, 2008

Earth as seen from Mars

There is a fantastic picture of Earth and its moon over on Astroprof's blog from 12 March. The picture was taken from Mars by the MRO. Go to his blog for details.

Also check out the picture of Enceladus and other info from the latest observations from Cassini, in a post from 11 March.

I find the picture from Mars extremely interesting, since it shows what an advanced civilization there (not to be confused with the one from Mars Attacks) would see with a high quality 19th century telescope. [Based on a wild guess at the aperture needed for sub 1 meter resolution (30 cm per pixel) from a low Mars orbit (200 km) and no atmosphere.] Earth would look very inviting.

On the other hand, Enceladus looks good for ice boating, winter rally events, and possibly ice fishing. The ongoing discoveries out there are amazing.

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Tuesday, March 11, 2008

Access to College

Stumbled on in a comment in Dean Dad's IHE blog. That comment on aligning college and high school expectations seemed like it really belonged in a different thread (probably the one on the high school college gap, but also relevant to the role of CCs in the STEM area) but it pointed to something I think is really useful. The connection is the point that CCs are often the major route out of poverty, which can include the STEM areas related to medicine (including nursing) and engineering, but this depends heavily on using a CC to make up for what you can get out of a failing school system.

Check out the documents developed by the League of Women Voters of California to advise parents on the value offered by the community college system in California and how to help their children benefit from it. Their "College Access for Everyone: Removing Early Barriers" report is also a succinct analysis of key problems, such as socialization, poor counseling, and the old standby in discussions on Dean Dad's regular blog, articulation.

It struck me that these documents could help us with some of our advising and institutional challenges.

On the advising side, they are targeting our audience: the kids with a marginal education who can't get into a "real" college, the kids who dropped out and earned a GED (perhaps at a CC such as ours), and the students who are not kids anymore (parents of children currently in the school system). I really like their data on pay levels and, more importantly to many of our students, public assistance rates as a function of education. I wonder if we put enough of a carrot out there to help convince them that there is a payoff for the work we are telling them they need to do.

But I digress. The strongest point is on pages 6 and 7, concerning the lack of information on how to proceed if they want a career in a STEM area or the technical or manufacturing spinoffs from those fields. They literally have no way of knowing what to do. I was particularly struck by the cuts in counseling in CA high schools, but I also remember that the well-staffed counseling office in my (well funded at the time) midwestern HS was of zero help to me. I was mentored about preparing for college by my father and a couple of teachers. The pointer in the parent's guide to a web-booklet called "First in the Family" available from an organization called What Kids Can Do.

Side comment: I also stumbled on some good advice from kids on helping them get their homework (and knowledge) organized so it becomes a useful study tool. If they aren't getting those ideas in HS, we need to supply them in our CC programs.

The other was a strong point about the lack of rigor in their classes and the need to develop study skills and self discipline if they wish to succeed in college. That is the area our STEM programs are attacking, and that I emphasize every time I advise students about their plans for next semester's classes. But we still need to do a better job of "connecting all the dots", as they put it, for kids still in HS. I've run on long enough, so I will save my biggest peeve (what passes for a passing knowledge of math) for a later article when I can do a better job of locating some sample tests.

One other detail that jumped out at me was that the number of non-graduates from HS jumped significantly when California added its "CAHSEE" exit exam. Not news to me, but then I read what Sherman Dorn writes about how it is possible to get a 100% graduation rate while half your students drop out, as long as the administrators launder the kids through an exit to GED program.

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Monday, March 10, 2008

J Sidney McCain the Third

Rather than just get exercised along with Ariana Huffington over an alleged congressman trying to slander Obama while maintaining Rovish plausible deniability, why not just counterattack? Two can play that game.

If John Sidney McCain the Third's surrogates want to use a middle name to slander a Democratic candidate with the lame excuse that it is "Presidential", why don't they (and we) use the full name of their Republican candidate? Got something to hide? Sure looks like it. Sauce for the gander, it seems to me.

John Sidney McCain III doesn't sound quite like the common man touch they have cultivated with John "Johnny Be Good" McCain, does it?

And it shouldn't, given that he went to a private prep school according to his Wiki biography. Sort of like the the preppie W he wants to replace, that detail would not quite fit the persona he has adopted as a politician.

Come on, Ariana. Call "McCain" by his given name, J Sidney the Third, until he stands up for his fellow Senator.

She also missed a chance to point out that when Orrin Hatch ... claimed that the terrorists "are going to throw everything they can between now and the election to try and elect Kerry." he was actually describing what the terrorists did to keep their buddy "W" in charge. Every time an election (congressional or presidential) rolled around, they went out of their way to reduce terror attacks and even endorse the person they did not want running the war. They knew the media and the "W" voters would be suckers for that ploy.

But Huffington is on the mark about insisting that someone claiming to be a mainstream politician should speak about against the lunatic fringe of his own party.
Each time one of those jerks forgets what it used to mean to be a statesman, every Democrat should call John Sidney McCain III on that and insist that he stand up for his fellow Senator. Anything less would violate the oath he swore as a Naval officer.

One other suggestion, while I am on the subject:
There is enough of a gap between primaries that Senators Clinton and Obama should figure out a way to worship at each other's home churches in Illinois on Palm Sunday or Easter Sunday.

And along the way, O'Bama should join the Kennedys and other Irish Democrats in a St. Patricks Day parade. They ought to be able to make up some green O'Bama signs in time for that.

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Sunday, March 2, 2008

What Students aren't told by Pick-a-Prof

Short version: The professor evaluation web sites don't tell them that they need to do homework.

The data shown here are not in a 1-to-1 match because they show two different cohorts and only a portion of what will produce a grade for the latest group. The top row shows a modified version of the graphs provided to students and faculty by Pick-a-Prof based on data from the last three semesters. (The change I made is explained below the fold.) The bottom row shows an analysis of the results of the first exam this semester. (That means some of the students in the Physics 1 grade distribution at top left took the exam shown for Physics 2.) The beige part of each column shows students who don't do homework.

So what data are we looking at here?

First, the percentages in the Pick-a-Prof tables do not add up because they exclude students who drop the class from their statistics and the histogram, reporting that separately. However, since failure to pass is a failure in our accounting (and that of engineering schools that count a withdrawal as an attempt), and since many of the F grades in my grade data will drop sometime by midterm rather than fail, I think drops needed to be included. I reconstructed that number from their data, so when you see 24% withdrew, that means 24 dropped for every 100 that got a final grade.

Second, the data on homework are from a simple comparison of exam scores to homework scores. The break point at 80% for the homework reflects something I have observed for years, and the fact that it is pretty easy to get over 80% on the homework if you put in only a fraction of the 2 hours of study per day in class that is expected for college-level work. These homework problems are all assigned on-line and graded automatically, with multiple attempts allowed.

Third, the first exam in Physics 1 is always "too easy". I could make it a lot harder, but I find that an easy test (where all problems can be done correctly if you know how to do all of the homework with the book closed) sends a better wakeup call to the half of the class who forgot to purchase a clue about doing homework when they bought the textbook they don't read before class. In comparison, the first exam in Physics 2 includes the challenging concept of Gauss' Law and more vectors and calculus than they had to apply in the first semester. They catch up when we start doing circuits, if they do the homework.

Random thoughts on the data

For the first semester of physics, the story is quite simple. If you don't do the homework, you likely won't pass the first test, let alone the class. The bulk of the students in the "did not succeed" grey bars were ones who did not do the problems that are at the core of studying (and doing) physics. Now you might notice that some of the failures had pretty high homework scores. This is also not unusual. If you do all of your homework with your notes and book open, following examples from your friends, or cribbing a formula from a Google search or one of several homework "help" sites, you learn as little as when you simply copied someone else's paper back when we collected homework and paid a TA to grade it. Some quickly figure this out, while others just don't want to do the work. Or can't do it.

The second semester is more interesting. Those A grades reflect the fact that some students start to trade off effort in the harder calculus classes they are in for effort in this class, particularly when they get what is going on. Most of those are still in the 60 to 70% territory, and many of them do the problems later (when studying for the exam) but don't get credit for it in the homework score. There are, however, a few who did not get the memo from last semester, including a few who wandered into my class from somewhere else. (The standards at Wannabe Flagship down the road or wherever they came from did not prepare them to study.) They confused doing well because they did the homework with doing well, and failed when they did not do the homework.

There is also another effect at work: Once you get everyone doing the homework, the overall proficiency of the class improves. This changes the curve, eliminating B grades (as you see in the Physics 1 exam distribution) unless you replace straightforward problems with ones that require more critical thinking. Indeed, this allows you to put some "thinking" problems on the exam, to fill the time they don't need when demonstrating proficiency. Of course, this really burns the kids who have not gotten proficient from doing the homework or thought about the conceptual questions (also in the homework) that lie behind the ones requiring more critical thinking. The first exam in Physics 2 had a couple of those questions, so 90% proficient on the homework would become a low C or D if you missed both of them.

Finally, a comment on the Learning College premise mentioned in Dean Dad's Live Blog, where he wrote one of the folks there mentioned that at his college, faculty annual performance reviews (!) include data on how many students in a given professor’s class achieved the ‘learning outcomes’ they were supposed to. If the students don’t succeed at an appropriate level, the presumption goes, then the professor has some serious work to do.

The data on homework in my classes show the flaw in that reasoning. Most of the students who did not achieve the Learning Outcomes they were supposed to if they wanted the passing grade that would get them into engineering school, have only themselves to blame. Two of the students in the F group in Physics 1 actually did not do any homework at all! Indeed, you can just about see where the 1/3 who failed in past semesters came from: the beige bar group at the bottom. The Physics 2 group has been whipped into shape. Everyone who is left in the class is passing, while a couple of the "no homework" group with an F on the first test have dropped, pretty much what you see in past data for final grades.

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Saturday, March 1, 2008


Fidel Castro announced his resignation on 19 February and was replaced by his brother Raul on 24 February 2008.

William F Buckley died 27 February 2008.

Coincidence? Whether it was or not, these two men were a fixture of my entire political life, for better but mostly for worse.

My first thought was that "William Fbuckley" was dead. Yet making fun of his name on Laugh In (right? Lily Tomlin?) hardly defused his importance in the culture wars (and the political naivete on the left, when they refused to compromise on Hubert H Humphrey's candidacy) that gave us 5+ years of Nixon and a taste of what could done with illegal wiretaps rather than jackboots. That really prepared me for this century, by the way.

On the other side, personal hatred of Castro has skewed US policy for over 40 years. Where trade with China has altered its "communist" state (and the lives of its people) dramatically since Nixon changed our embargo against them, our embargo with Cuba primarily serves to give that government an excuse for its own failures. A system that fails primarily because it is built on a confusion between a clever and successful debating argument by Marx about the nature of human economics and the reality of actual human behavior.

That is what Buckley and Castro have in common, in my mind. Buckley could also craft a brilliantly written argument, such as the one that segregation was just fine as long as the majority of blacks were too ill educated to meet his criteria for participating in politics. (Begging the question of how they would get educated if the system that subjugated them did not change.) However, he forgot that this was not just a Yale hallway debate, but an action giving immoral support to those who would murder black citizens in the name of maintaining segregation in both the south and the north. To his credit, he seemed to have changed his mind on this matter, but he never really admitted that he had helped oppress human beings rather than merely participate in a speculative academic argument.

Buckley also appeared to sell out his original libertarian strain of true conservatism, with its rejection of prohibition and many drug laws and massive Reagan-style spending, when he saw a chance for Reagan to come to power. I wonder if he ever realized that he had been used, in the worst sense, to sell something as alien to his main views as the reign of George "W" the (forty) Third has been.

And now a bit of a digression, a thought about someone who would see the connection between them even more clearly: Lincoln Diaz-Balart.

Here is a man who could call Castro "Uncle Fidel", but would rather die first because he was from the Batista side of the family reunion picnic table. I wonder if he sees Buckley as a hero for promoting a narrow (and originally quite racist) view that America should be run by a ruling class, perhaps just as the Cuba of his youth was run when his father was part of the ruling class in Havana.

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