Category Archives: Education

H1B to be Square

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In the past we’ve been told that there is a shortage of tech workers (or rather , there isn’t because we can import them), and businesses have demanded more visas or suggested other solutions to the problem.

Now they’re saying we have enough, they just are leaving the field for richer professions:

The supply has actually remained steady over the past 30 years, the researchers conclude from an analysis of six longitudinal surveys conducted by the U.S. government from 1972 to 2005. However, the highest-performing students in the pipeline are opting out of science and engineering in greater numbers than in the past, suggesting that the threat to American economic competitiveness comes not from inadequate science training in school and college but from a lack incentives that would make science and technology careers attractive.

In addition, the current economy has temporarily eased the problem (if it is a problem)— applications are down because fewer companies are hiring.

I’m beginning to see a more consistent picture here, if it is indeed the case that potential sci/tech workers simply choose other, more lucrative fields. Recipients of H-1B visas only have to be paid the higher of the prevailing wage for the region, or the employer’s actual average wage, but if that average wage is for an average employee, and your visa recipient is more capable than that, you can drive the salaries down, much like evaporative cooling lowers temperatures. Employers are not forced to pay higher wages for highly skilled US workers, so they diffuse to different fields. The average salary can drop, but the skill level increases, and average skill levels must accept lower wages as long as there is a supply via the visa program. Whether this is actually what’s happening, I don’t know. I don’t think the “we’re not capturing their interest” model is discounted, and it’s likely that multiple factors come into play in figuring out why there aren’t more science students entering the workforce.

I disagree with the proposal that we need fewer science students. There’s a mistaken notion that if you don’t directly use your degree in your adult life that the system has somehow failed, and I’d hate for the result to be less emphasis on science. The utility of learning science isn’t that everyone will become a scientist by profession; we want students to learn English literature and philosophy and some even major in these subjects, but do we expect philosophy majors to all become professional philosophers? The utility of science is that it helps teach us critical thinking, and the ability to separate truth from fraudulent mumbo-jumbo helps protect us from those charlatans who would try and peddle perpetual motion machines, or tell you the earth is 6000 years old, or convince you that vaccines cause autism. I agree with Zapperz on this

As far as I’m concerned, my interest in physics education is more towards having student be literate in physics and how it is done, rather than trying to gear them towards specializing or majoring in physics. I don’t care if they end up as physicist or not, but they shouldn’t be ignorant of what physics is, and how we gather our knowledge.

Grad School is like a Startup Company

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Paul Graham: What Startups are Really Like

The cofounder is your thesis advisor. There are many points with a pretty decent correlation to life in grad school, at least for physics, and my datum.

I’ve been surprised again and again by just how much more important persistence is than raw intelligence.

Not that physics grad school is populated with dummies or anything, but persistence is mandatory.

I’m continually surprised by how long everything can take. Assuming your product doesn’t experience the explosive growth that very few products do, everything from development to dealmaking (especially dealmaking) seems to take 2-3x longer than I always imagine.

Ask a grad student how long until the get their degree, and you’ll probably get an answer like, “I just need to get this one bit of apparatus to work, get a little data, and then it’s thesis-writing time. I’ll be done in a year.” A year later, you will probably get the same response.

When I was in school, we filed a plan of what coursework we would be doing for our degree, which was reviewed and approved by your thesis committee. It had to include a certain number of research credits, which basically amounted to one year of full-time research. A friend of mine asked, “What happens if I finish sooner than that?” which elicited a round of laughter from his advisors. “We’ll deal with that if it happens.” He had done two years of classes at that point, and was there for 5 more years.

Be a Choosy Mother

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Choose to give to Donor’s Choice.

Two physics-y blogs that have set up links are Cosmic Variance and Uncertain Principles

Last year Chad collected more than a monkeydance worth of donations, and he is once again offering various kickbacks for donations exceeding a certain threshold. Cosmic Variance will put your name in lights, if the coin is big enough.

If any other physics blogger has their chapeau in the torus, let me know and I’ll add the link, or you can do so in the comments.

My Life is a TV Teen Drama

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I don’t generally watch the teen-coming-of-age drama shows, unless forced (as I was on vacation; the episode of Degrassi was a cheap ripoff of Pump Up the Volume without the benefit of a topless shot of Samantha Mathis), but I’m sure this plot has been covered somewhere: Awkward Teen asks the Beautiful Cheerleader to the prom; she has recently split with Handsome Quarterback, but doesn’t immediately say yes to AT, so he assumes she will say no and asks Safety Date, who is much more likely to want to go with him, and she says yes. Immediately thereafter, BC also says yes. Depending on the context, either tremendous angst or hilarity ensues. Possibly both, depending on the quality of the writing.

How does this apply to me? A while back I got an invitation from an old navy buddy to give the keynote talk at the Southern Atlantic Coast Section of the American Association of Physics Teachers Conference. Keynote speakers are typically either famous, to some degree, within either the physics or pop-physics communities, or are attempting to become so by promoting a book, so I am not the Beautiful Cheerleader in this scenario. I figured this was an act of desperation, but I agreed, thinking it would be fun. Lo and behold, it turns out that the other speaker can make it. (Cut to commercial)

All is not lost. I’m getting my own slot during the conference, though that will be a tad awkward — the after-dinner talk (and the public talk that some conferences have) has more leeway in not being directly related to the theme of the conference. I don’t have any particular insight into teaching to share; certainly not an hour’s worth. Same goes for a lot of themes that show up here — I don’t want to make the mistake of trying to turn a 5-minute skit into a feature movie, because it rarely works (are you listening, Saturday Night Live?) So I’ll go with my plan and talk about clocks and timekeeping, with a few cartoons thrown in, and leave the connection to teaching as an exercise for the interested viewer. I was going to do a bit about how I’m at least a little bit famous, and promote the blog, and I may leave that in.

I was also toying with the idea of going with a minimalist presentation, with very few slides in the first part of the talk. The show-and-tell part, though, really needs the “show” as much as the “tell.” Still working on that. I lose the comfort of the “1 – 1.5 minutes per slide” guideline, and since talks will follow mine, there’s pressure to finish on time.

Hey, Buddy, Can You Spare a Few Hundred Thousand Dimes?

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STUDENT DEBT vs. AVERAGE INCOME

I graduated with about $10k in debt from college, much of which was deferred while in the navy and again in graduate school. I paid off the last of it more than 15 years after graduation. I incurred no debt for grad school — teaching and research assistantships paid a stipend as well as tuition. Having a few times that amount of debt would have been tough.

Doing it Right

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Illuminating physics for students by David Griffiths

Physics teachers are fortunate (I am among friends, so I can speak frankly): ours is a subject the relevance and importance of which are beyond question, and which is intrinsically fascinating to anyone whose mind has not been corrupted by bad teaching or poisoned by dogma and superstition. I have never felt the need to “sell” physics, and efforts to do so under the banner “physics is fun” seem to me demeaning. Lay out our wares attractively in the marketplace of ideas and eager buyers will flock to us.

What we have on offer is nothing less than an explanation of how matter behaves on the most fundamental level. It is a story that is magnificent (by good fortune or divine benevolence), coherent (at least that is the goal), plausible (though far from obvious) and true (that is the most remarkable thing about it). It is imperfect and unfinished (of course), but always improving. It is, moreover, amazingly powerful and extraordinarily useful. Our job is to tell this story – even, if we are lucky, to add a sentence or a paragraph to it. And why not tell it with style and grace?

Griffiths came down to Corvallis and gave a talk when I was in grad school. It was pretty good — I felt like I almost understood Berry’s phase when he was done. (OSU had its own David Griffiths; fortunately they did not annihilate upon meeting)

I found a particular resonance with this comment

I have known people who are in some sense too smart to be clear; they cannot remember what it was like not to understand something, because, I suppose, they never had this experience. They may be outstanding physicists, but they do not belong in the classroom.

When I was teaching, and later when merely explaining, I’ve tried to understand the misconceptions people have, and the barrier that the misconceptions create. It’s not enough to tell someone that their answer is wrong — they need to understand why it’s wrong, too. Remembering what it was like to not understand something is really useful.

Grabbing the 'Aha' Moment

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The US isn’t the only country having trouble teaching high-school physics. Australia has similar issues.

Physics teachers not up to scratch: study

One quote caught my eye:

“The person that’s teaching them might have some competence in science but just can’t grab that ‘aha’ moment.”

Not that I’m endorsing under-qualified high-school physics teachers, but I suspect that the ‘aha’ moment for science happens before high school. There are a lot of opportunities for teachers to turn students on, or off, before the teenage distractions show up in life. And physics tends to be taught last in high school science sequences, so the potential audience has already dwindled if students are turned off by chemistry or biology.

via

Science? Pew!

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Pew Science Knowledge Quiz

To test your knowledge of scientific concepts and recent scientific findings and events, we invite you to take this 12-question science knowledge quiz. Then see how you did in comparison with the 1,005 randomly sampled adults asked the same questions. You’ll also be able to compare your Science IQ with the average scores of men and women; with college graduates as well as those who didn’t attend college; with people who are your age as well as with younger and older Americans.

I got 12/12, but I’d expect anyone with a science degree to do pretty well — this is targeted to a lay audience. And it sets the bar pretty low; numerous bloggers have discussed the poll results and implications. The poll is reasonable, I think, with two exceptions. One is a question that is not so much science as current events, and another is the type which becomes harder to justify when you know more about the topic. Look at the quiz first, though.

Continue reading →

Check

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I noticed a very important lesson in Rhett’s post July 4th and an example of work-energy: checking the answer.

Let me make some checks here. Will the acceleration be positive? Yes. The first term will always be positive and greater than g because (d+h)/d is greater than 1. What if a jumper jumps from a higher height (h). This would make the acceleration greater. What if the jumper stopped in less water, this would also make the acceleration greater. Finally, does this have the correct units? Yes.

Notice how Rhett isn’t checking the numerical answer — this is a check of the equation that leads to the numerical answer, to see if it’s reasonable. There’s a lot of power in doing this that one loses when the numbers are substituted too early in the process. While you can do the first and last checks — direction and units — the trends of what happens if a variable changes is removed. And checking the limiting behavior of an equation is a tremendously important tool as the questions, and resulting conclusions, get more complex.

Now, once you get the answer, you can check that for reasonableness, too. As I mentioned some time back, when I taught we stressed getting answers that made physical sense, else your math mistake be tagged as a conceptual error. You should not be deducing that a frog has a mass of 10^24 kg; one can check this by relating the mass to known objects (in this case, being a measurable fraction of the mass of the earth) which requires having some awareness of masses (or forces, energy, etc.) on different scales. Or can apply the long-lost art of estimating the answer from the number you put in. All numbers become 1,2 or 5 and you round aggressively — but the rounding often cancels, and you can get pretty close. At least close enough to be within a factor of 10 or less of the right answer.

And some of this is shown in sciencegeekgirl’s Teaching the gentle art of estimations which includes a simple estimation problem which was a complete disaster when asked of some teenage students.

The conclusion I draw from this? We’re doomed.

Interestingly (ironically?) the very last example has a number I question. The force of impact of an object falling under the influence of gravity is much larger than mg.

Acceleration goes as the velocity of impact divided by the time of contact. What is the time of contact? The bottom of the ball hits the ground, but the top keeps going until it gets the signal that the bottom has hit, that there’s no more room to move down, and it’s time to start moving up. That happens at the speed of sound.

And from that, a time of 10 microseconds is concluded, giving a force of 10,000 mg (i.e. an acceleration of 10,000 g’s. Wow!)

I balked at that (and commented in the post). The object doesn’t recoil that fast — that’s the limiting case for the top to know that there has been an impact. One needs to look at the spring constant of the material to know what’s going on. 10 microseconds is too short — the contact time is almost certainly much longer. How much longer, I wonder? A convenient scale with which I am becoming familiar is shutter speed. 10 microseconds wouldn’t be discernible on a high-speed camera, if I had access to one. Which I do.

You need to a flashplayer enabled browser to view this YouTube video

This is at 420 frames/second, and since I have the advantage of being able to easily click through frame-by-frame on the original, I’ll tell you the answer: the ball is in contact for ~4 frames, or just under 10 milliseconds. IOW, almost three orders of magnitude longer than the speed-of-sound estimation.

Cause and Effect

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Dean Dad asks

Why do so many states require only two years of math in high school?

[…]

We have anecdotal evidence that suggests that students who actually take math for all four years of high school do better in math here than those who don’t. We also have anecdotal evidence that bears crap in the woods. Why the hell do the high schools only require two years of math?

And there is followup at Uncertain Principles

There is a lot of discussion, so I may have missed someone raising the following point:

People who take four years of math and do well are probably good at math. Whatever distribution of students took the math for two years, I’d bet that it’s not the same as the distribution who took it for four. I’ll bet the players who go out for (pick your sport) do better at that sport in gym than the players that don’t, because you tend not to pursue and enjoy an activity if you suck at it.

The discussion seems to be dealing more with the other reasons why schools don’t require four years of math. I can ignore that for a moment and still assume an ideal case not limited by the availability of teachers or caused by bureaucracy. To me, the proposed solution embedded in the rhetorical question is not the head-slap obvious conclusion.