Thursday, April 26, 2007

Delivery boys on strike

Today, I ordered lunch from Saigon Grill, a good Vietnamese restaurant on the Upper West Side. They couldn't deliver because their delivery boys are on strike! I of course ordered from somewhere else, but I was left completely baffled: How can the delivery boys for one restaurant maintain a strike in Manhattan??

Thursday, April 19, 2007

Spring is here, swing is here

Today, the weather had improved to the point that I went swing-a-ringing again.

Here's my first swing video, made in August of last summer:

Tuesday, April 17, 2007

Kerry vs. Gingrich, climate change

Video here.

Kerry vs. Swift Boat Veterans for Truth

"Mr. Senator, when I'm asked [for money], I just generally give."

Monday, April 16, 2007

Why any document dumps?

Just a quick question about the US Attorney purge investigation now underway.

The White House is being awfully secretive, invoking executive privilege on an unprecedented range of topics. They may or may not have "lost" over 5 million emails, some of which may contain damaging information. And yet there have been several "document dumps", releasing several thousand pages of emails and other documents related to Department of Justice communications.

My question: Why? There has been some damaging information in the document dumps. Why have they bothered to cooperate at all, when they don't have any shame about flagrantly disregarding Congressional requests and even subpoenas?

Tuesday, April 10, 2007

Pole vaulting

This is DA reader MB attempting to pole vault 16'9".


Monday, April 09, 2007

Don't confuse weather with climate

It's a cold April. That doesn't mean the world isn't warming. Just as the warm December and early January weren't dispositive proof of anything, either.

I will note, though, that the 70 degree days in December were a bit creepy; and this was the first winter ever on record in which there hadn't been a snowfall in New York City by January 4th (the first snow didn't happen until January 11 this year).

Also, if you hear global warming deniers saying that Mars is warming too, direct them here. The basic point is that Mars probably isn't warming. Some people erroneously inferred warming from receding polar ice caps, but Mars is getting less solar irradiance than it was 5 years ago. The South Pole ice is receding, so something besides a brighter sun is causing the ice to disappear. It's not clear what it is, but it IS clear that it's not a global phenomenon.

Friday, April 06, 2007

Modest proposal for universities too:

This will be a short post, and I'll expand on it later. It's motivated by the same thinking that led to this post and this one.

It's kind of funny that colleges and universities are run by boards of trustees. At unionized campuses, professors have to negotiate for their contracts and benefits with these boards of trustees. It's almost as though the boards of trustees are the owners of the university. But of course they don't own anything. What could they own? They don't own the buildings, the land, ... anything. It seems to me that professors are the group who do the most to make universities run (although this is changing as institutions of higher learning are relying more and more on less expensive short-term labor, like graduate students and adjuncts). Therefore, they should run the university.

Of course, professors shouldn't be managers. But they should hire the managers (president, etc.), not the board of trustees.

Thursday, April 05, 2007

What do I want students to learn?

Background:
As a graduate student in astronomy at Columbia, I was required to teach an undergraduate astronomy lab course that's a companion to the introductory astronomy lecture course for non-science majors. I enjoyed teaching this course very much, and I did it for 6 semesters. During my last year of teaching, I was the named the head teaching assistant, which is sort of a misnomer for this course, because we don't assist anyone in teaching it but instead design and teach it ourselves. In my capacity as head TA, I was at least nominally responsible for monitoring the curriculum that other instructors came up with for their classes. Although I didn't really like the feeling of monitoring my peers, I am very interested in pedagogy, and I've read a fair amount about science education and have attended several conferences on it, so I liked thinking about the relative merits of different kinds of curricula.

Just a little more background — Barnard students are required to take a year of lab science courses, and the Intro Astro Lab course that I taught is one among many lab science courses that fulfill this requirement. So, most of the students in the class are Barnard students who want to get this requirement out of the way.

In fact, I know this is true: At the beginning of every semester, I passed out a questionnaire that asked, among other things, why the students are taking the course. Occasionally I'd get answers something like, "I've always been interested in astronomy." But, by far the most common response was, "To fulfill my lab science requirement." To my students, astronomy had for some reason seemed like the least painful way to pass this hurdle on the way to graduation; or maybe, since astro lab meets at night, it was the only course that fit into their schedule.

Teaching Non-Science Majors:
I have spent hours, weeks, and years of my life thinking about what I want to teach the predominantly non-science majors who took my Intro Astronomy Lab course. Unfortunately, I'm still not confident in an answer.

(a) Since my students were not astronomy majors, there wasn't really any specific astronomy knowledge or set of astronomy skills that it was critical for them to learn by the end of the semester.
(b) Furthermore, since biology lab or geology lab would also have fulfilled the lab science requirement, clearly Barnard isn't interested in making sure that all of its students learn any astronomy; instead they must hope that the students will get something out of the course beyond specific facts or skills relevant to one particular field of science.

These two realizations gave me a great deal of freedom to shape the course. But, as Spiderman reminds us, with great power comes great responsibility.

There's a relatively easy way to teach an astronomy lab course. As the instructor, decide on some astronomy facts, principles, and skills that one wants to impart to one's students. Then, each lab class will consist of lecturing to the students for long enough to explain all the nuances of the lab, and then having the students work through some procedure for figuring out the answer to some question. Along the way, they will learn some astronomy, and they will reinforce some skills. The instructor will more or less hold their hands along the way, making sure that the students feel comfortable while they work out whatever it is they're working on. I don't pretend that this is easy — there are major questions the instructor must address, about what content to teach and what exercises will be best (most efficient? most fun? something else?) for teaching this content. But it's easier than the alternative.

The relatively hard way to teach an astro lab course involves figuring out a way to get the students to think scientifically, and to be scientists.

Motivated both by what I think Barnard hopes its students will learn and by what I think the students will be capable of remembering 1, 3, 10, or 30 years from now, I arrived at the following goals for my course — during my course, students should:
  1. learn the scientific method: science involves observing the world, making hypotheses (falsifiable models or predictions), and observing the world again to see to what extent it matches the predictions.
  2. become investigative practitioners of the scientific method, specifically,
  3. (i) observe the world, (ii) think of questions about the world, (iii) hypothesize answers to the questions, (iv) think of methods to answer the questions, (v) carry out the methods, and (vi) analyze the results of investigations.
  4. become more comfortable talking about science.
  5. learn to think about the meanings of numbers. This means,
  6. (i) think about how many digits are significant, and, as a matter of scientific integrity and honesty, don't report more digits than are significant, (ii) understand what a margin of error or uncertainty is, (iii) think about what physical thing is being described every time a number is reported, and finally, (iv) don't reach for a calculator every time you have to do some simple calculation.
  7. learn how to use a telescope.
  8. come to enjoy thinking about science in general and astronomy in particular.
I don't care if they learn how far away the Large Magellanic Cloud is, or if they can reproduce a Hertzsprung-Russell diagram a year from now, and if I don't care about those things a year from now I don't think I should be too concerned if they learn those things now, either.

But how do I teach a lab that results in them becoming better scientists?

It's very hard to get students — especially students with a rather weak science background — to pose interesting, tractable questions about astronomy. So, I often eschewed astronomy in favor of more tractable scientific problems that were inspired by astronomy.

Basically, everything we do in lab as fits into at least one of three categories:
Exercise (e.g. point the telescope, or calculate this distance using parallax)
Experience (e.g. watch this demonstration)
Investigation

And, there are two kinds of investigation: guided or open-ended. In a guided investigation, the instructor poses the question, and the students think of how to answer it. In an open-ended investigation, the instructor provides a rough topic or framework, but the students think of the questions they want to answer and the methods by which to answer them.

If I tell the students how to answer a question, then I've turned what they're doing from an investigation to an exercise. Although there is certainly some benefit to exercises (they help reinforce knowledge or skills), I cared much more about developing their investigative minds (goals 1., 2., and 3., above) than about developing knowledge or skills. So, I spent as much time on investigations as possible, and I assiduously tried to avoid telling the students how to answer questions, or even what questions to ask. I worry that too often in lab courses, items 3. (ii) and (iv) above (in italics) are almost entirely overlooked; I tried to give the students lots of opportunity to do both.

But it's very easy for an investigative lab to make the students feel that the instructor is passive-aggressive. The instructor holds information that the students need, and yet refuses to give it to them. Why won't s/he just tell them how to answer the question? And the students have a response: stall. When the students stall for long enough, the instructor can feel forced to give them what they want so that they can complete the lab before the 3 hours are up. Doing this can have a terrible effect: "Oh, that's what you wanted us to do? Why didn't you just say so?" Well, I didn't say so because there wasn't anything in particular that I wanted you to do; what I wanted you to do was to think and come up with a solution on your own. But the damage is done.

Teaching a lab in an investigative manner can also make the students feel less comfortable, and it can therefore be less fun for them. I'd hate to think that I worked much harder than I otherwise would have, I made the students work harder and feel less comfortable, and in the end they have learned less astronomy and learned that astronomy is no fun. I'd hate to think that 3 years from now their memory of astronomy lab will be, "that time when that passive-aggressive teacher made me suffer pointlessly for 3 hours each week".

Jacob Noel-Storr, who was the Head TA when I started graduate school, had some excellent advice when I was in my first year of teaching: Never lecture, never use the blackboard, and be aware of how much time you are spending talking relative to the students (and make sure this ratio is small!). Of course, it's practically impossible to avoid ever lecturing or using the blackboard, but, if you go into lab with the intention of never doing these things, you end up doing them a lot less.

I believe it's safe to say that in my entire time teaching the lab course, I never spent more than 10 straight minutes talking at the students, and practically never spent more than 3 or 4 minutes talking at them. Many labs, I didn't even talk for more than a minute straight. I kept my blackboard usage to what felt like an absolute minimum, maybe venturing to the board on average 6 times in an 11 week semester.

This advice goes a long way toward addressing goal 4. Instead of me explaining things to the students, I had them explain things to each other. I had them present their results in every class. I often noticed students who were shy at the beginning of the semester become much more comfortable talking about science by the end of the semester, and I feel very good about this.

Goals 5.-7.: I explained why significant digits are not just a procedure for truncating answers so as to make teachers smile, but rather a matter of honesty (I hope they apply this concept to the terribly innumerate world out there); in general, I always made sure they were aware when they were not being adequately attentive to the meanings of numbers; and I had them observe with a telescope as often as possible. I hope that these lessons stick with them as they go through their lives, encountering political polls, descriptions of the efficacy of one medicine versus another, etc. And I hope that using a telescope is at least somewhat like riding a bicycle, and when they have a house in the suburbs someday they can show their kids how to point a telescope at Saturn.

Goal 8? This gets back to my huge fear. Was the extra effort (on my part and theirs) wasted? Did I make them suffer and at the same time lay the groundwork for a future of loathing science and astronomy? Gosh, I hope not. I'm sure that in plenty of cases my students felt very positively about astronomy by the end of the course. But, on the margin, could I have taught them roughly as much (or more) — while along the way making more people feel more comfortable, have more fun, and ultimately feel more positively about astronomy — by teaching the class in a more traditional manner?

Tuesday, April 03, 2007

Hasselhoff.

Hooked on a feeling.

Big Box Mart

Oh Big Box Mart.

Goodling's 5th Amendment assertion invalid:

From a letter (by Reps Conyers and Sanchez) quoted at TPMuckraker about Monica Goodling's asserting her 5th Amendment right to avoid self-incrimination:
The fact that a few Senators and Members of the House have expressed publicly their doubts about the credibility of the Attorney General and the Deputy Attorney General in their representations to Congress about the U.S. Attorneys' termination does not in any way excuse your client from answering questions honestly and to the best of her ability. Of course, we expect (as we are sure you do) your client to tell the truth in any interview or testimony. The alleged concern that she may be prosecuted for perjury by the Department of Justice for fully truthful testimony is not only an unjustified basis for invoking the privilege and without reasonable foundation in this case but also so far as we know an unwarranted aspersion against her employer.

This sounds right to my uneducated ears. The 5th Amendment says
No person shall ... be compelled in any criminal case to be a witness against himself....
But this has not historically been interpreted literally. People still must show up in court, and must assert the 5th Amendment privilege on each question that might cause them to be witnesses against themselves.

Although I'm not a lawyer, it seems to me that since Ms. Goodling has not been charged with any crime, it is particularly difficult for her to assert a privilege based on fear of her testimony being used against her. Of course, she may properly refrain from answering any question whose truthful answer would show that she had committed a crime. But the letter that Reps Conyers and Sanchez wrote to Goodling's lawyer makes a strong case that fear of an unwarranted prosecution for perjury is not a valid basis for asserting the 5th Amendment privilege. (If it were, then any witness could use this excuse to get out of giving any testimony any time, and subpoenas would rendered impotent.)

Monday, April 02, 2007

A very nice man

I only met Bob twice. First, 2 years ago at a lovely Passover Seder that he hosted with his wife Cindy in Memphis. Next, a few months later at my sister's wedding that he again helped to host at the family's home near Schroon Lake, New York. He was a kind man, unpretentious and attentive to others. When I first met him, I appreciated that he was mindful of my inconvenient dietary restrictions (on which I was very insistent, having just adopted them). He and Cindy made hosting people look easy, even with a crowd of 30 for Passover and over 100 for the wedding.

He just passed, while teaching how to play the card game Bridge, on a cruise. This was to be the first Passover he would miss in a long time. He was too young.

I'm very glad I had the chance to meet you, Bob. I feel very badly for my brother-in-law, Cindy, my sister, and the rest of the people who knew him much better than I did and must feel his loss more acutely.

Sunday, April 01, 2007

Stephen Weinberg writes very well.

I like this essay very much.

The prestige of religion seems today to derive from what people take to be its moral influence, rather than from what they may think has been its success in accounting for what we see in nature. Conversely, I have to admit that, although I really don't believe in a cosmic designer, the reason that I am taking the trouble to argue about it is that I think that on balance the moral influence of religion has been awful. ...
As far as I can tell, the moral tone of religion benefited more from the spirit of the times than the spirit of the times benefited from religion. ...
With or without religion, good people can behave well and bad people can do evil; but for good people to do evil—that takes religion.

He sure knows how to turn a phrase. Is he right? I'm not sure. Even if he is, you could just as easily say "...; but for bad people to do good — that takes religion." Which sentence is more right? Don't know.