Saturday, May 30, 2009

Down - and UP

Found this video when I went to IMDB to look for the links in the discussion below.

Click on this link to see the animated short film Headwinds. It will be well worth two minutes of your day. Gravity wins in this film, which features many of the classic bits of bogus physics common to cartoons where a character falls off of a cliff, but an accurate treatment of many others.

(Some minor spoilers follow.)

As for Up ... we had a blast from beginning (including the trailers and a great Pixar short called Partly Cloudy that takes the stork creation myth one step further) to end. Only disappointment is they cut the credits short to clear the theater for the next crowd, but the dog jokes more than made up for that. (All I could think of at a few points in the movie was Chad's promo movie with his discussion of a Schroedinger's Treat experiment.)

Some nice technical work in this film. "Partly Cloudy" must have been used to do development work on clouds and cloth (cloth got a specific mention in the credits), and there was some really nice work with fabrics in our hero's tweed jacket and a montage near the start where changing styles of ties was used to symbolize the passage of many decades. There was also a breathtaking shot of water flowing in a stream, looking down from above. If you don't follow animation, water and fire have always offered some of the greatest challenges. I think they have completely mastered flowing water, just as they did with the rough chop on the ocean as The Incredibles flew to the island.

One subtle detail was the homage to Miyazaki, a good friend of Pixar's founder: One characteristic of films by Hayao Miyazaki is the use of flight in some form or another. If you have ever seen Porco Rosso, the appearance of an airship in this film was no surprise. And was the rotating weather vane an homage to the Disney classic, Mary Poppins, as these two firms join forces? Could be.

The only blatant continuity error I noticed was that the kid did not seem to be on the porch while the house was flying through the sky, and we saw under the house as it lifted off. However, there was a subfloor under the porch - so he could have been in that crawl space IF there had been an opening for him to use to get in and out.

Saw it in Digital 3D, which we HIGHLY recommend. Wouldn't see it any other way. This is the first time we have seen Disney's 3D, and we were very impressed. Heck, we were impressed with the Disney movie logo! It may seem odd, but the most striking aspect of the 3D depth to me was during the camping scene at night. The stars in the sky looked really far away. The depth was natural, not contrived. In fact, unlike the trailer for the 3D kids film about raining meatballs, there were only one or two instances where they pulled the usual 3D stunts of the past.

And we know about 3D stunts, having sat through Jaws 3-D mainly because we had been in a crowd scene in the movie while on our honeymoon trip to Orlando. We sure hope Toy Story 3D doesn't die a deserved death like that movie did! (The 3D trailer for it is pretty well done, but about all it tells you is that they are making the movie and have a release date for it in June 2010.)

Where does Headwinds fall down, physically?

The treatment of air drag during free fall is really good, and I'm not complaining about the great cartoon moment at about 0:57 where he claws at the air, suddenly falling out of his shoes when he realizes he is in trouble. No, the real problem is that the rock is much denser than he is, so it would have passed him on the way down - long before he pulled his parachute. His terminal velocity is much MUCH less than that of the rock ledge that he knocked loose.

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Cool Old Instrument

Interesting article via the BBC feed today about reconstructing a Roman-era trumpet that was used in European music through the early 1700s. Apparently, one piece of music by Bach, a motet (BWV 118 based on the title given in the BBC story and what I found on Wiki) was scored for this instrument; a new recording of that piece of music can be heard via a link in the BBC story.

The instrument was reconstructed by using a computer model for trumpet-like instruments to design something that had the tonal range and other properties described in old descriptions of its use. That is one heck of an application of the numerical solution of partial differential equations!

The rapid response team that exists on Wikipedia answered my question before it could even be asked. I had wondered (based on the picture in the article) if the Lituus was in any way related to the curved war trumpets used by Roman armies in Hollywood movies, or the straight ones (looks like it was called a tuba because it was basically a tube) you see used to herald the arrival of Caesar or to coordinate troops in battle. The answer seems to be "yes".

The music produced by mixing voice with this instrument is really haunting. Not exactly as upbeat as one would expect from a modern song with a title like "Jesus, the Light of my Life", but beautiful in its own way. I wonder how it would sound with the additional presence resulting from being played in a church with stone walls.

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Thursday, May 28, 2009

RBoC on Teaching

I spent several hours today over at Wannabe Flagship's engineering school today. My goal, which was fully realized before I even got in the door, was to run into some of my former students and glean what I could from them about what parts of my physics classes are most useful. The relevance to "teaching" was that one of them invited me to sit in the back of his mechanics class. Was that ever an eye opener! I'd forgotten just how bad some R1 faculty, particularly fairly new ones, can be when it comes to teaching. More on that at the bottom of this entry.


The first part of the discussion of the first chapter of "The Gender Knot" is underway. I described the origin of that discussion about a week ago. So far, I find the book quite interesting. Might even be blogworthy at some point.

  • A DL Heads Up from NISOD

An IHE story from the NISOD conference in Austin describes some current thinking about Distance Education as its role expands on campus. I say "heads up" because I know our college wants to expand in that area, and I doubt that they fully realize that there might be major additional costs (one department had to add an administrative position just to manage faculty in distance ed classes) or issues with cheating. (There I am reminded of the scandal, well known among sports fans, where a large fraction of the Florida State football team was cheating on tests for an on-line class, with the assistance of academic support staff.) By the way, if you don't know what NISOD is, clearly no one at your college is drinking the Kool-Aid. I noticed several points in this article where they referenced "quality classes". No one ever seems to worry how that adjective was assessed, or what to do about putting "non-quality classes" on line.

  • Summer Teaching

I found this article in IHE very entertaining and full of good advice for new faculty. I know lots of our young faculty teach a heavy summer load just to increase their income, but I'd hate to see them burn out. (The fraction of summer classes taught by adjuncts has plummeted as high-salaried retirees have been replaced by low-salaried new Assistant Professors. Must be the student loans.) Personally, I teach a very light load in the summer, a course that I don't normally teach. Thus, I fall in the "different teaching experience" with "more diverse and focused" students category. But there is no way that a 6 week semester is laid back! And some of my students this summer must be from Wannabe Flagship, seeing the way several missed class (and a key review topic) the day before an exam.

Some of my students need the lesson described in this article about what the author learned about learning from Lenin and Father Roderick. But I don't have to go back thirty years to find students who knew how to study. I had students like that last summer, and the summer before. This group seems slow to realize that they need to take my class seriously.

  • Right Hand - Left Hand

Consider this article about un-tenured professors in higher education (about a book that looks exclusively at elite R1 universities, and excludes grad students from its examination of adjunct faculty at those universities) and another about the emphasis on research at universities, particularly those where the research is NOT externally funded (hence does not contribute to the bottom line like it does at major R1 universities). This last category might include "regional comprehensives" that are upwardly mobile, probably not unlike the one that Dr. Crazy blogs about when it isn't summer.

One comment on that article correctly pointed out that quality research is the only way you can get tenure at an R1, which merely indicates the writer is clueless about just how much that research is subsidized by student fees because the salary that pays for research is generated by a 1/1 load. But in that case the university hopes to profit from the substantial "overhead" on the grant, and gladly pays adjuncts to pick up the teaching slack. [See the connection to the other article?] The question at hand is about schools where the research generates no money, and yet uses up valuabe faculty time that MUST subtract from teaching. You can't teach class every day AND do effective research AND invest thought in your teaching at the same level as when not doing research.

Today's Teaching Observation

First, I wasn't exaggerating about running into a student before I even got in the building. A guy who is now a senior was outside on a smoking break, and then a student from last year saw me from the lobby and came out and joined us. He was the one who told me about the mechanics class and showed me where to slip into the room.

I learned a great deal watching the train wreck that was the lesson in progress when I slipped into the back of that lecture hass. (By the way, the beauty of a large class of 50 or so in a larger room being led in traditional lecture style is that someone like me can slip into the back row and hardly be noticed despite my obviously thinning hair. The sad thing is that it would have been great fun if the lecturer had noticed and called on me! The sadder thing is that he didn't call on anyone or walk around the room to see what was going on during his "group problem solving" exercise.) You can learn a lot by seeing someone make mistakes that you made yourself the first time teaching physics as a grad student.

What was that mistake? When he decided to work the problem rather than have them work it, he jumped from place to place in the solution (a bit of free body here, a bit of a constraint there) without ever articulating the most important step: identifying what the problem is, what we need to find to answer it, and how we were going to go about finding the one key unknown BEFORE working it out. And, when working it out, work through the standard steps in standard order. I'd hate to see what their notes looked like (if they had any), since the approach was so scattershot. It literally did remind me of a grad student approach, where the answer is already obvious to the instructor and the "solution" process stays below consciousness in the instructor's head, with only random bits getting free associated into consciousness and onto the board to justify specific things that needed to be calculated.

Like I said - entertaining as all get out, but I felt bad for the students.

I also had some great interactions with former students who are now last-year seniors, and former students who are in their first junior year of engineering classes - including two that were in that class I observed. Several of them really reinforced the importance of free-body diagrams in my intro class. And I also got a chance to talk to a department chair to clarify one of those annoying "articulation" issues and, along the way, learn his views about the importance of relevant examples in the math curriculum.

All in all, I had quite a lot of fun and learned a lot this afternoon.

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Monday, May 25, 2009

Effective Transfer

There was an interesting article in IHE Friday about the importance of that most mundane of topics, "articulation" between a CC and a nearby University to ensure that transfer students succeed. The focus was on Texas, with a number of examples coming from UTEP. The specific success of a very tight articulation between the UTEP engineering college and its neighboring CC (towards the end of the article) was particularly interesting to me. I need to look into what they did and how they documented the comparable skill level of their AA grads after they got a BS.

Having read a number of comments about the Texas system (or lack of one) from a commenter in (IIRC) Dean Dad's blog, I found the short discussion of "high policy" and "low policy" states lacking in depth. From what I can gather, Texas is in the middle with a defined "core" but no structure that ensures that an "Associates" degree meets that core. It was definitely weird to read about needing to design a computer search to find students who have the credits to earn an AA degree, but don't know it yet.

Ditto to read about "reverse transfers" who drop out of a university, come to a CC, and immediately (without even taking classes, it seems) earning an AA. Instant transcript laundering, it would seem. Do they just ditch all of the credits earned beyond two years, along with F grades and whatever, and start over as juniors at a new university? But I do agree that it would be a great way to build your "completion" rate - if it was true. The author of the article must not know that "reverse transfer" students are never counted in any of the federal statistics. Only the cohort that actually starts at a college (or university) is counted when figuring success rates.

We could have a 100% success rate at shaping up dropouts from nearby Wannabe Flagship, with every last one of them getting an AA and going on to complete a 4-year degree after they left our CC, and none of it would count in our favor.

So, now that you know this factoid, you have to wonder how the guy at North Texas can conclude that there is no difference in success of transfer students in states with a defined transfer curriculum (strong state-wide articulation) and those without (where students might have to re-take half of the classes they took at the CC after they transfer). What data are being used? Besides, I think success after transfer is more a matter of the relative rigor of the CC and Uni curricula (which affects the odds of failing classes) than it is of the number of classes that actually transfer with gen-ed credit (saving money and time).

Rigor cannot be enforced by state policy, or even a common course numbering system. Heck, you can't even guarantee that different sections of the same course at a particular college have the same rigor. I can see dramatic differences between some of the math sections at our college. Some get the concept of "prerequisite", others don't.


What makes for a truly effective transfer program?

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Health Memo

Saw this story today from the BBC news feed, about a link between "middle age spread" and later health problems related to frailty in old age, and immediately thought of my brother ... and me.

Definitely something to keep in mind.

Time to get away from the news feed and do more than yard work to stay in shape. I remember back when I had to make the transition from just going skiing and having to train to be in shape for skiing. Now I need to start thinking about staying in shape for old age, so something as simple as a fall doesn't ruin my life.

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Saturday, May 23, 2009

Russian Space Station Plans

According to this very interesting article, Russia is planning to take a very different long-term approach to space exploration than the US. Rather than abandoning and destroying the International Space Station in just 6 years from now, perhaps 10 years in the more optimistic scenario, they want to reconfigure the Russian modules and use them as the basis for a long-term space-based construction site.

This is not much of a surprise, really. The US kept the first multi-crew space station (Skylab) manned for about half of a year, then watched as its orbit decayed - crashing back to earth about 5 years later - because we had no ability to launch a spacecraft to maintain it. We shifted all of our (limited) resources to the Shuttle, which could have done the job it it had not been delayed by several years.

We have a short attention span, jumping from one project to another. Our next one is a direct return to the moon. Building that next launch vehicle will surely have so many delays that we won't be able to get back to ISS even if we wanted to. Its continued operation into the next decade will be a result of vehicles built and operated by others.

Russia, on the other hand, kept Mir in use for more than a decade, learning how to maintain a space station over a long period of time. Their plan is to let the US decouple all of its modules and destroy them, using a new junction module (needed because the current junction modules belong to the US) to assemble the Russian components into a station that might become the first "space dock".

From the end of this article:

Unlike the ISS, which was advertised primarily as a platform for scientific research, Russia's future space station, dubbed the Orbital Piloted Assembly and Experiment Complex (OPSEK) would have the primary goal of supporting deep space exploration.

Behind the scenes, Russian engineers have drawn up ambitious plans for orbital stations around the Earth and the Moon, and eventually in the orbit of Mars. These would be linked by re-usable tugs, shuttling between them continuously to support the sustained exploration of the Solar System.

After separation from rest of the ISS, the station's 20-tonne service module could eventually be replaced by a 40-tonne living quarters launched by a new family of launch vehicles.

In turn, this module could ultimately serve as a construction site and a base for the Martian expedition complex, which could be assembled in Earth orbit in the mid-2030s to carry the first humans to the Red Planet.
Very interesting.

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Friday, May 22, 2009

NIF story

The National Ignition Facility is the latest in a series of large lasers (really, a large complex of lasers) developed at Lawrence Livermore National Laboratory in California. Actually, "large" does not do justice to the size of this device. I've seen an earlier version, and that facility was huge. This is bigger.

BBC News has a very good article about it, including several informative embedded videos.

NIF, like what came before, was built to study nuclear fusion reactions in the laboratory that result when a pellet of hydrogen fuel is compressed by laser beams. Unlike what has been used before, NIF was originally planned to test a potential design for a fusion power reactor on a scale that allows study of the feasibility of engineering and building an actual power plant.

It is a slight exaggeration to compare this to the reactions that power the sun. The sun "burns" individual protons to heavier nuclei, so you can think of its fuel as being regular hydrogen gas. The reaction employed here, like in other fusion reactors, uses heavy isotopes of hydrogen (deuterium and tritium) as fuel. These react more easily, and produce a large energy output.

I could write more - a lot more - but that will be it for today.

Reference Links:

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Wednesday, May 20, 2009

RBoC - mostly education related

I don't have a theme here, just some quasi-random articles that caught my attention over the last few months, none of which rate a full-blown blog. I'll just toss them out here and see what sticks.

This actually does deserve an entire blog response, but I don't have the energy left to engage with it. This has been quite the year for me - not all of it bloggable. What I will say here is that I really like her commentary, particularly the way she starts off by recognizing that we should not change simply for the sake of change. There is a lot that is not broken, and that part needs to stay unbroken! I probably share this view because there is a lot right at places, like my CC and her 4-year regional comprehensive, that serve a wide range of students who might not otherwise be in college. Also a lot that needs work.

I really like her suggestion that we "increase the chances for students - across university types, across backgrounds - to have their minds blown." I've never articulated that, but I can tell when my students really appreciate that they just got EDUCATED in a way they never thought possible.

Now that I am teaching some 75 to 80 minute classes, I suspect that even college students need recess once in a while! That really is the limit. My version of recess is to schedule a Cool Demo (tm) near the middle of class, to change the pace. But this is also a serious issue. Our schools have no recess, and schedule what PE they do have at the end of the day. A friend is convinced this is why his very bright son struggled with attention in school. He didn't need drugs. He needed to get out and run around! Count me in that same group.

Somewhere on the boundary between futurism and engineering is the question about how to remake this country as we move beyond our previous three revolutionary developments: railroads, interstate highways, and the internet. BTW, I love that map, mainly because I've driven on way too many of those blue and red lines.

Isis provides a world-class rant here. The leaky pipeline photo is worth the price of admission. I know one thing: the complaint that got her started sure didn't come from the physics or engineering side of the academic universe. And in chemistry, where there are a lot more women, the pipeline tends to have tap that sends a disproportionate number of female faculty away from universities and over to places like our CC. (The story probably comes from biology. The poor boys might even have trouble getting into med school. I'm not going to complain, because my internist is a woman and a very good doctor.) Along that same line ...
A hat tip to Zuska and her outreach project for this one. I've got to reassess my time (and access to my wife's Kindle) and see if I can read that book in time for her planned discussion. Since the last serious reading I did on this subject would be when I read Kate Millett's Sexual Politics (back when it came out), it could be time to get caught up on the gender culture wars.

Personally, I don't buy that grades are still being inflated. There isn't any room for them to grow! (Well, we could have "weighted averages" like our local high schools, where you get an extra point just for taking a hard class that you should be taking anyway if you plan to go to college.) I've got this in here mainly so I might remember to dig out the data I have from a previous lifetime that shows the grade inflation at Ye Olde Alma Mater. Most of it took place during the Vietnam War, but it does continue. I have some data (well after that time period) showing that the only college that really failed anyone at all was the one that taught science and math classes. No surprise there.

These days, as those data show, CCs seem to be the only place where students are failed for not having the relevant skills ... and even that seems to be too little from where I sit at the end of the math line, trying to teach physics to kids who still have trouble moving symbols around to solve equations. One of the comments pointed to an essay saying that our education system needs more F's (coming out of the K-12 area).

There is a lot of information in this article for a data geek like me. There mere fact that the "catalog cost" (what it costs just to take the classes required by the curriculum in the college catalog) is about 30% more for mechanical engineering than elementary education is a real eye opener. When you look at the "transcript cost" (which includes repeats, courses like pre-calculus that a student might need, and courses taken when a student wanders off the beaten path), the premium for engineering jumps another 30% or so. Not surprising, since I know my pre-engineering students are usually in the CC for an extra year, and I also know that they have 2.5 years of engineering classes to take after they transfer.

I wasn't surprised by the 260 k$ price for an MD, except that I thought it seemed LOW. I looked at university budgets some time ago, and one thing that jumped out at me was the massive costs of running a medical school. I suspect that some costs have been put into the research area that are really part of the cost of any graduate program. I don't quite buy the "full cost" analysis, where you spread the cost of failing students over the ones who pass, but I can see it from the point of view of a legislator. And it also makes sense based on the "more F's" argument above: the quality of the person who graduates is partly a result of the selectivity of the process that produces that graduate. You don't want engineers who design bridges that fall down.

I find this interesting for many reasons. Two of them are the article that follows (accreditation) and my own college's attempt to reach into some really bad local high schools, but also the fact that much of the attrition at our CC is by students who have no idea how weak their HS education actually is. (See my old article on orientation and advising.) A college class could engage them in a way that HS does not. The fact that you don't need an ed degree to teach that college class, pointed out in one of the comments on that article, can only add fat to the fire of some other discussions. But what really interests me is that I think the best way to assess the "outcomes" of a school is to look at what happens next. Are HS graduates ready for a job or for college? Clearly not, as our placement tests prove every fall. Are our CC grads ready for the university? Not always. And we need to look at that. I am told (all in the form of anecdotes) that mine are, but I'm not satisfied by that kind of "data". Time to make the trek to Wannabe Flagship and see what I can learn.

I have to include this, and I have to bury it at the end of the list. Why? Because I have been through the "Quality Improvement" plans and know that "Outcomes and Assessment" will be the fashion the next time around ... and I have serious doubts whether most of this is only for show. Paper to file and boxes to check off. Our plan looks great on paper (really great, actually) but we have heard nothing at all about how we have progressed on it. I can guess that ideas X and Y have not worked at all, because they have been de-emphasized ... but results have not been reported and they have not actually been eliminated. I think the people behind them have too much invested to admit they did not work, so they just move on and jiggle the key, hoping it will start. See also what Dr. Crazy wrote, in the article linked up at the top, about keeping the focus on students.

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Tuesday, May 19, 2009

And now, something completely different ...

Advanced Cat Yodeling

Hat tip to Icanhascheezburger.

But that is only part of the story.

That is less than half of the full video. Click on this link to see the full six minute engineer's guide to cat yodeling WITH cat polka video. I love the "fist" bump about 4 minutes in, and that one of the cats is actually a dog, but the opening "free aspect ratio" bit and the "protection" needed when first annoying your cat ... those are priceless.

Be sure to check out some of the video responses.

And if you never saw their first video, an engineer's guide to cats, check it out, too.

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The Link

At least the racing (Formula 1 at Monaco, Indy 500, NASCAR Coca-Cola 600) should be over with on Sunday, leaving Monday free for this prime-time program.

The Link will be on the History Channel at 9 pm EDT on Monday, 25 May. This program has been carefully hyped, with a cast of the fossil put on display today in New York City amid a massive press promotion.

An excellent news article from the BBC includes a link to the "PLoS ONE" journal article (published today, 19 May 2009) about the fossil - which was discovered 26 years ago and sold two years ago to the University of Oslo, reported for a million dollars.

This is a remarkable fossil. The high resolution version of the first figure in the article, showing the fossil, is really remarkable. You can see the fur! But the program pushing this as the "missing link" is quite a stretch. The timing, in particular, makes the whole process look suspect. After all, when the TV program airs less than a week after the journal article appears (just a few months after the article was submitted), it does look like marketing the TV program and the exhibit in New York drove the publication rather than the other way around. Was this how the Oslo museum planned to pay for its purchase of the fossil?

That said, here are my dos centavos:

In my totally unprofessional training as "lifetime reader of the National Geographic", this seems a bit over-hyped as a direct human ancestor. The article itself doesn't really make that claim (which seems to come from the TV program promotion), probably because the most one can claim is that it is a extinct primate that could have evolved into either a lemur (less related to us) or a monkey (more related to us). But how do they know - for sure - that another known line didn't evolve into what became primates and humans, or that there isn't yet another, as yet unknown, extinct primate that actually did that? And they clearly aren't claiming that this is the parent of both sub-types of primates.

Actually, I've been reading the National Geographic since before I was born. My grandfather had a seemingly complete collection going back to the 30s, which I estimate based on having read about the 1931 balloon ascent of Piccard in his library. I've read all sorts of articles about discoveries about human ancestry. Each new discovery one would read about in that magazine, often by the Leakey family, added new information - as did later (also hugely hyped) discoveries like Lucy. There is nothing like actual new data to stir the pot and update the lineage. And nothing like National Geographic sized publicity to try to sway people to your side of the debate.

I haven't had a chance to read all of the ScienceBloggers on this subject, but the argument by Brian Switek seems to run along those lines. The argument seems to be between a small group (including the authors of this new paper) that think Apapids led eventually to humans, while many more think the vast bulk of the evidence favors Omomyids and Tarsiers. (The many links in the "classification" part of this article, particularly about the Haplorrhini, make following the evolutionary discussion much easier. Now I know that lemurs are on the wrong, wet nosed Strepsirrhini side of the evolutionary divide leading to humans. The authors would not like my visual comparison of their fossil to a lemur.)

But don't take my word for it. Go read the journal article, Switek's critique, and whatever else shows up in the next few days.

One other thing:
The weakness of conclusions drawn from partial fossils is pretty clear from the paper. The first half of the fossil, purchased by a Wyoming museum in 1991, was misclassified by the authors of this article. As a physicist, it always bothers me when conclusions are drawn from incomplete data or, more precisely, an incomplete datum. They didn't even have a full data point until they looked at the other half of the fossil. I'm glad I'm a physicist, where we can repeat experiments where the results seem incomplete.

Updated: Link links -

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Thursday, May 14, 2009

Graduation Speeches

I lucked into having the right channel on last night when Obama's grad speech at ASU came on live. It was outstanding. His riff on the theme "you haven't done enough to deserve a degree from us" led to a series of challenges to the new graduates.

Check out the text from the Huffington Post and video (Part 1 of 3) from CNN and YouTube. There are plenty of good ideas in there to steal if you need to give your own graduation speech some day, particularly if you are looking for a turn on the usual riff on "commencement" marking a beginning rather than an ending.

If you need other ideas ... check out what Dean Dad had to offer in his letter to graduates, and this make believe speech "given" at the make believe U of All People.

Obama is definitely a master of using self-deprecating humor to deflect his critics, not to mention a master of any crowd. I particularly liked the way he called out various majors (education, nursing, engineering) and, after they cheered hearing their name said by the President, challenging each of them to do something for the country. Definitely an "ask not" moment, but directed specifically at young people entering far more challenging times than we faced in 1960 and, in a way, directed specifically at each individual student in that group.

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Sunday, May 10, 2009

Kids These Days ...

Hat tip to Jennifer Ouellette at Cocktail Party Physics for this clip of Louis CK on Conan O'Brien:

Everything is amazing, nobody is happy...

I love how he carries on with a "Bad Codger Attitude" (hat tip) despite not being all that old ...

... like his comments about dialing a phone. Kids these days don't know that the reason we have "800" numbers for free long distance (what was originally "WATS" lines[*]) is that it was so hard to dial those higher digit numbers. That is also the reason that the access code for long distance is a "1" in the US (we ruled telecommunication back then) and the original area codes for big cities were easy (like 212 or 313) and you definitely knew when you lived in a backwater town (an area code starting with 90). Now it doesn't matter, but we still "dial" a phone!

... but particularly his comments about flying. Except there are a lot of people who don't want to know they are 5 or 6 miles above the ground (they don't know what 35,000 feet means in real numbers) or ever look out of a window. I think they don't actually believe in flight.

Yeah, I'm that old, but I was also paying attention as a little kid.

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Saturday, May 9, 2009

Star Trek

Finally got out to see Star Trek, and all I have to say is that the movie exceeded all of my expectations. I'm no crazed fan (that would be my wife), as I never watched the series until it was long into reruns, but I know all the old episodes and new movies ... and this movie was really good.

Freakishly good, as I said to my wife on the drive home.

It must have been an even number in the sequence of movies.

As for the science [spoiler alert], others have done a better job than I would take the time to do. But I will add my comment that I thought they did a much better job with inertia in general. Sure, the old standby, the "inertial dampers" that got rid of the annoyance of Newton's First Law, was disabled by the time the Kelvin had its collision (or was it ... there was still gravity and gravity was allegedly produced by the same system), but it was good to see Capt. George Kirk go flying when the ship stopped. Ditto when Kirk and Sulu were beamed out of free fall and landed on the transporter pad.

[bigger spoiler alert]

And, best of all, they have freed up the time line so they can make an entire new set of movies that don't have to be consistent with ANY of the others. Brilliant.

Easy way to explain away the glitzier bridge, Spock's higher voice, the appearance of people in the original crew that were not in the crew during the first season ... and a significantly less crippled Captain Pike in a conventional wheel chair.

Next stop: Rebuilding Vulcan? Will Spock and Uhura have a son who will go on to play golf with both style and cool analysis? Or become the next President? They have managed to re-energize the series in a way that moves it from the 60s to the 21st century, opening up new story lines to make it relevant again.

Note added:
I can't wait for the Director's commentary to find out what chemical plant or brewery or distillery was used to film some of those scenes inside the ship. Who knew that steel "I" beams were used inside a starship!

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Problem Solving

The comment from FUG led to a nice little blog about chemistry with a clever title, although I hope his future is centered on experimental UNCERTAINTY rather than experimental ERROR!

For some reason (my money is on a bug due to use of M$-specific java crapware), I can't comment on blogger driven blogs that use "comment_from_post_iframe.js" like his does. It simply does not recognize my selection of the pull-down menu. As a result, I will comment here on one of his recent articles. Another article, an undergrad's view of the chemistry -v- physics "fight", has potential as a jumping off point for a look at why so many engineering students dislike chemistry. What "type" of person prefers one over the other?

Here, I want to look at his article about a basic static equilibrium problem of a beam and a mass.

He gets off to a pretty good start, drawing a nice, clean free-body diagram. That is essential, and the only thing missing is the location of the center of mass of the stick and the fact that an unknown force "mg" acts there.

But his next step is not the most important one. Rather than notice

the fact that the meter stick isn't moving

and identify the problem as a STATIC equilibrium problem (with the implications that net torque = 0 will likely be used to solve it), he grabs the equation for accelerated motion and worries about the moment of inertia of each object. That would only matter if the same situation was described, but you were told the angular acceleration of the system at a particular moment. (That would make a good problem. Make a note of it.)

His "simplest solution", using the fact that the system's center of mass must be over the support point, is equivalent to solving the net torque = zero problem. (Another mental note: I need to point that out, because we encounter those two ideas at rather different points in the course.) The key to finding that solution is at the very start, when classifying the problem type. That step is triggered by the key words "it is balanced" in the question.

That is where "critical reading" enters the problem-solving game.

And I happen to think that it is more important to spend time on "critical reading" as a component of problem solving than some of the tricky concepts. But that is the subject of the yet-to-be-written next blog entry.

Regarding the observation
The human mind can only compute so much.

I can only say that I agree, but the limits on it are the result of training, experience, and focus. For example, when fully immersed in the problem, I know I can hold the essentials of about 10,000 lines of Fortran computer code in my head (along with all of the associated physics), but can only manage parts of a 100,000 line code in that way.

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Friday, May 8, 2009

Physics WITH Calculus

A hat tip to Chad at Uncertain Principles for a blog about calculus "based" physics that jumps off from a very good article by Thoreau. (He also points to another article by Thoreau that I intend to blog about, but first things first.) I won't quote extensively from either Chad's or Thoreau's articles, so I'd recommend reading Chad's article for background and another point of view.

As I said in the comments about Chad's article, I teach a physics "with" calculus class that, like the one Chad teaches, has the first semester of calculus as a co-requisite. This significantly reduces, but does not eliminate, the use of calculus in the first semester course - as I will explain. The second semester is another kettle of fish entirely. I should also say that I use (and love) Wolfson's "essential" textbook, but like some of the pedagogy in books by Knight and Redish. For example, I wish Wolfson did momentum before energy like Knight does, and resistance before capacitance, like Redish does. I don't like how any of them use calculus. By way of background, I should also add that I first taught out of the "blue bible" edition of Halliday and Resnick. which used little calculus at first, but I learned physics (with lots of calculus, since differential equations was a co-requisite) from the Berkeley physics series of textbooks.

So, what are the issues, from where I sit?

1. One issue is whether calculus SHOULD be a prerequisite for calculus-based physics. That one comes up regularly in discussions with my colleagues, although the fact that nearby Wannabe Flagship (where most of my students transfer) has calc as a co-requisite makes it pretty much of a moot point. It's not like my class has less calculus in it than theirs. (I think it might have more.)

The main concern about the math requirement concerns "success" rates. Would students do better if they had passed calculus before taking physics? The answer is a hearty MAYBE, because "passing" calculus is a surrogate for "knowing algebra and trig". This is supported by research, by the way. Students who are taking Calculus 2, which is harder than Calculus 1, will fail (or drop) if their grades indicate weak algebra and trig skills, while those taking Calculus 1 will thrive if they got an A in our pre-calc and trig class. Problem solving skills and the ability to follow a non-trivial sequence of algebra steps is the key to success in physics and calculus, and would not be any less important if we had more calculus in physics.

One way of putting this is to say that students would do much better in physics (and calculus) if my math colleagues failed 70%, rather than merely 50%, of the kids who take pre-calc and trig at our institution. This would not make the powers that be very happy, however.

A related concern has to do with getting them into physics in a timely fashion. Students at a CC tend to be there because their math is weaker than the norm. Although Wannabe Flagship has its share of students who enter needing to start in college algebra or pre-calc, they get a lot more of the ones who are allegedly prepared to take Calculus 1 and Chemistry 1 during their first semester. (Allegedly. Some of them end up at our CC shortly thereafter.) When a student has to take three (or more) classes before calculus, they are almost done with their other AA courses before they even get to "freshman" classes in the pre-engineering curriculum! Some actually run into problems with financial aid due to some restrictive rules put in place a few years ago. They aren't ready for "junior" classes in their major until they complete 3 semesters of calculus and two of physics, so anything we can do to help them fit math and physics into their remaining time with us will help them succeed. And, as I noted above, if they actually learned algebra at some point, they do just fine.

2. A key issue, the one raised by Thoreau and implicit in Chad's article, is the importance of calculus to physics. Is it important enough that students need to know calculus before taking physics so it will be part of the subject from the first day?

Well, it must be important if Newton had to invent it to do some key problems he developed within the Principia, but having had just such a course (see above), I am not convinced that it has to be central to Physics 1. Solving the anharmonic oscillator was fun and interesting, but it didn't add much to the physics content of the first semester mechanics course. It is important enough that it must be in there, but not so important that it becomes a math class.

However, my experience says that calculus DID add a lot to the other parts of the course, and I let that inform the way I teach the second semester of physics. To give just one example, I solve the simple, undriven, undamped harmonic oscillator problem in Physics 1 using basic methods from differential equations, since everyone can do the chain rule with sines and cosines by that point. That is pretty minimal calculus content. However, in Physics 2 I solve the undriven, damped LRC circuit using complex exponentials, and make the explicit connection to the classical mechanic problem I skipped over. I also give them plenty of homework and exam problems where they have to do "simple" derivatives and integrals as part of the solution.

Is that enough to jump straight into Lagrange's mechanics? Probably not. But where I was an undergrad (and at Wannabe Flagship) they got (and get) less than that in their first-year course, so Intermediate Mechanics had to start off with a review of things like the driven-damped problem. In addition, they also need a review of Lagrange multipliers. Even if it got taught in their differential equations class, the odds are approximately zero that the math prof teaching the class emphasized the importance of this method in physics or engineering.

I've also talked to some of the engineering and physics faculty at Wannabe Flagship, although the one kid every year or two who becomes a physics major means my concerns are mostly with engineering. Their point of view is that they want their students to know both physics and calculus, separately, and well. They will help them put them together. IMHO, if you can figure out the free body diagrams and write out the correct equations, the rest is "just math" that might be solved with Maple or MathCAD for a real problem. They seem to agree, and have at least one "intro" course that has that as its main objective.

But there is another extreme, and I think that is what Chad and Thoreau are talking about. Back in grad school, I had an instance where a student took the wrong final exam for Physics 2. I was teaching trig-based physics, and he took the calc-based exam that was in a different room in the same common final exam block. He was a C student in my class, and he passed the final exam in the calc-based course! We gave him credit for it, and made a mental note that the engineering students were not exactly being challenged more than the pre-meds were. I don't think that is the case for the exam I give.

2A. Why can't they fix the calculus curriculum? I'd be a lot happier if they covered all of basic differential and integral calculus in the first semester, skipping all of the functional analysis, and put limits and continuity into the third semester when developing partial derivatives. That would also make more room for applications problems in calculus.

3. Finally, how does one use these books, which uniformly minimize calculus, if you want calculus to be in the class? Well, I push it in there, kicking and screaming, first in lecture and later in homework and exams.

In Physics 1, I put problems that require taking the derivative on the later exams and/or the final. Thoreau is right about the dearth of good problems in the books we use, but I write my own when they don't suffice. But my emphasis is on problem solving, not math. I'm more than content to ask a problem where they have to SET UP the differential equation or integral. That is the physics part of the problem. Similarly, I always have problems that only ask them to draw the correct free-body diagram(s) and write the set(s) of equations to be solved, without solving them. I can ask much harder, messier problems if I don't expect them to solve them - and don't have to try to grade an attempt to solve the indeterminant set of equations or non-integrable function they came up with in error!

My emphasis is on problem solving. That is a big enough challenge, along with other basic skills. I liked the comment about torque from an engineer in the discussion of Thoreau's article. You see, I know that engineers call it the moment, M, and tell my students that. That is also a subtle way of telling them they need to be able to evaluate the torque next year as well as this year.

But I will also add calculus-based examples as needed. I insist that they read the book, so I don't have to repeat something that is adequately covered there. I can use examples to fill in the gaps, showing how the basic method can be extended to more interesting situations.

4. I'll close with one quotation from Thoreau's article, an observation that works as a segue to the next article, about teaching concepts. Thoreau writes:

As near as I can tell, they [people interested in physics pedagogy] believe that calculus (a subject to which no less of a physicist than Newton made huge contributions) doesn’t have much place in the freshman physics classroom.
[Side comment: Hey, I'm from the school that says Newton invented it, even though I know Leibnitz did it independently and the idea itself had been around before either of them.]

That certainly would explain why certain textbooks push a thousand pages and still manage to have very little calculus in them. They clearly think developing conceptual understanding comparable to that of an expert on physics pedagogy is as important as problem solving, and that both are much more important than using advanced mathematics within the course. I think this is wrong mainly for the reason that led me to tag this article in the "prerequisites" category: If we don't use calculus in our physics class, we are telling our students that they should forget calculus as quickly as they learned it, that they don't need to retain it for next year. I use it, and tell them as often as possible (and sometimes get my "alumni" to tell them as well) that the "next level problem" would use calculus here, or there, or there, and give them an example when feasible.

And (as I will elaborate later) I think emphasizing that idea, that the basic skills from physics and calculus will be used next year and need to be learned and retained, is much more important than some of the concepts that are displacing calculus from the textbooks. After all, some of the most important concepts and skills have NOTHING to do with calculus. Consider torque. Sure, you have to do an integral to figure out the torque due to a force distributed over an object (like wind load on a building), but is that integral more important than knowing how to handle a cross product? I don't think so. You can learn how to add the integral if you can evaluate the torque due to a simple force, but you can't if you have no memory of how to compute a torque correctly.

PS -
It won't be long before I teach Physics 1 for the 20th time, tweaking it as I go. My plan for this summer includes hanging out at the nearby engineering campus and getting some feedback from recent students and their faculty on what does, and does not, need more emphasis in my class.

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Thursday, May 7, 2009


As seen in the comments on Dean Dad's blog yesterday:

Check out this "featurette" preview of a new fall show on NBC called Community. As in "Community College". The full screen version on hulu is higher quality than this embed, but here you are (sorry about the leading ad):

Trust me: It is definitely worth four and a half minutes of your time if you teach at a CC. Heck, it wouldn't have been that far off the mark back when I was a grad TA at a major state R1! Like the guy who ate peanut butter straight from the jar during a 10 AM class. Was it a late breakfast or an early lunch? Who knows, but it had to stop.

Anyway, as I said in a side comment on DD's blog, I used to think that "Big Bang Theory" hit too close to home to the extent that it resembled my days as a physics grad student, but this show has the potential to disturb me very deeply. You see, only some of our students are HS losers. Some choose to come here to save money, with our lower tuition, which is a big deal these days.

And I don't know if the one character is a Dean (talking about why he is at this college) or a Psych 101 instructor (based on the Rorschach blot on the wall), but neither one has a bottle of wine on his desk - at least not with the door open. But the set decoration? Exquisite, right down to the boxes with an old computer display on top.

So is it, as they claim, "A smart comedy about higher education and lower expectations"? Maybe, maybe not. Maybe only if I lower my expectations for the program itself. But my friends and colleagues will all be waiting to see if (and how) they treat math or science classes. College Algebra, anyone?

Dean Dad blogged about the program here. I like his emphasis on the positive. I hope it does show, by example, the approach that leads to success at a CC.

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Wednesday, May 6, 2009

Age Distribution at ICC

Apropos a discussion over at Dean Dad's blog, here is an approximate, randomly normalized histogram of the age distribution of students at Ishkabibble Community College at some point in the not too distant past.

Details below the fold.

It actually does look a bit like the Maxwell-Boltzmann distribution, as I mentioned in a comment over at DD's blog, but it could just as well be a Lorentzian, or any of several other shapes with a long tail.

Lacking any better information (these are from some of the data our institution is required to make publicly available so they are easily obtained), I put everyone in the "under 18" category in a bin at 17 years old, and spread the population in large age bins uniformly across those ranges. You probably can't see that there is an actual thin line above age 55.

You can see that the peak (mode) is at 19. The average (mean) is around 24, and the median (half above, half below) is around 20. Most (if not all) of the students in the 17 year old bin are probably dual-enrolled high school students.

As I said in my comment at DD's, we are primarily a transfer institution where a large fraction of our students come to us directly out of high school. If you take the AACS Fast Facts, the subject of DD's blog, at face value, we are far below the national mean age of 29 and also below the likely value of the national median age, 22.

An important detail:
This data set is only for classes taken for credit and excludes a large number of students who are taking various non-credit "workforce" classes that we offer. They make up about 15% of our total student body and probably have a very different age distribution. If those were included, and they could be included in the AACC stats, our average age would likely increase.

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