Saturday, January 30, 2010

Laser fusion milestone

What better way to mark the 50th anniversary year of the laser than by producing a 669 kJ laser pulse (reported in Science), and then following that up with a 1 MJ pulse? (See BBC News article.)

Maybe getting it over the 1.2 MJ threshold and observing ignition of controlled thermonuclear fusion? This year?

They claim that it can be done this year, even though they did these initial experiments without the neutron shielding in place that is needed before doing that experiment because of the energetic neutrons that are produced by the d-t fusion reaction.

Read Entire Article......

An algebra problem

A story from the tutoring room, where I encountered a student taking first semester chemistry for science majors who was struggling with a simple density problem.

(Why they teach complicated algebra problems before they teach any chemistry is a mystery to me, but I no longer remember what pedagogy my chemistry classes followed.)

Given that our chemistry class has college algebra as a prerequisite, I think the problem itself is instructive.

After a significant amount of prompting on an easier problem, the student was able to get all of the given data for this problem into the appropriate chem-SI units of g and cm. This left something like the following problem, except written as a fraction:

2.705 = 276/(30.48 * 1219.2 * X)
Solve for X.

The student was,it appeared, utterly helpless when faced with all of those numbers.

My suggestion that he cross multiply the X and 2.705 met the sort of look I would expect if I had said it in Japanese. OK, clear fractions? Still no luck. I don't think he saw this as a fraction. Multiply both sides by X? Ah, progress. Now he could compute the right side and solve 2.705*X = Number. Just to check, I asked him about
5 = 7/(3*X)
No problem there, although slow as molasses doing it.

When I started telling this story to a chemistry colleague, she starting laughing so hard that she almost fell out of her chair before I was halfway through it. She regularly sees this at the start of every semester. Now I know why she says my students aren't like hers. Many (but not all) of the kids who make that kind of mistake are weeded out by pre-calc and trig before they get to me.

When I asked a couple of math colleagues about this problem, I learned that they include problems with "messy" numbers on pre-calc exams, but not in college algebra. They also said they suspect that not all pre-calc classes give messy application problems. So that is why I was not surprised that a student in Becky Hirta's Calculus Circus had trouble with a graph where the answer was not obviously going to come out in simple integer steps.


Two of my physics students messed up a problem essentially as follows:
2.66 = 7.79+3.47*X
2.66/7.79 = 7.79/7.79 + 3.47*X
0.3415 = 3.47*X
To save you the effort, 2.66/7.79 is about 0.3415. Bet you didn't know that 7.79/7.79 was zero!

Yep, that is how at least two of them "canceled" that number that was added on the right. Again, my math colleagues tell me that this sort of error is not uncommon among students entering calculus 1, and that they are more likely to make it with numbers rather than symbols. I have to wonder if they would have subtracted 7.79 if it had been at the end
2.66 = 3.47*X + 7.79
instead of at the beginning....

Read Entire Article......

Sunday, January 17, 2010

Engaged Learners

I don't have a label for students? Well, I do now. (I'm not going to file it under peeves because it doesn't peeve me.)

Regular readers know that Rudbeckia Hirta is the wind beneath my wings at the start of most semesters. Like today, where she tells me her university has FOUR different kinds of "undecided" majors, going all the way down to "completely undecided". I smile just thinking of that student wandering aimlessly through academia.

But I digress. This post is about starting your homework, well, a bit late.

You see, I have some quasi-administrative duties that put me in charge of dealing with student problems with a homework system during times our college doesn't have anyone handling user support. So what do I see in my inbox this weekend, which is the second weekend of the semester, but 3 (count them, three) problems getting into the system. Haven't gotten one of those for days, and now three of them.

Does this sound like either this problem or this one from RH? Well, it would if we had started class this week, but we didn't. We started the week before, so it takes a special level of engagement to wait until the Sunday before the homework is due to see if you know how to get in.

Disengaged engagement, I would say.

Reading those e-mails after reading RH's blog was like deja vu all over again.

My students, of course, have homework due right away (like RH, on the Friday of the first week of class for a Wednesday start). I find that if you coddle them with a late start, they don't start. And I make sure the slackers know that the vast majority of their fellow students have done the problems the day before they are due. The instructor for one of the classes involved takes the opposite approach. Not a good idea, but it was useful to see the flaw in that plan confirmed once again. But I do need to talk to him about that.

Like I said up above, I'm not peeved. I'm just an amused spectator like when I read RYS. I'm gambling that these students will never make it to my physics class, but they will get quite a wake-up call on the first day if they do make it there.

Or on the third day, but that is a different story.

Read Entire Article......

Friday, January 15, 2010

Jobs - Redux

There have been quite a few jobs-related articles on IHE and in the blogs lately that deserve linkage and comment. I'll put those below, after pointing to the jobs category where I group articles I have written in the past. The series started with a pair of articles that looked at the supply side (focus on the cycles we have seen over the past 50 years) and demand side (focus on where the jobs and will be) for physics, but much of what I describe is being lived today by folks in history and humanities.

The biggest difference between physics and the liberal arts area is probably that 2/3 of Physics PhDs have always ended up working in industry, with only a short (but very significant) period when the vast majority went into academia. Significant because it resulted in a faculty that remains woefully ignorant of where most of their students will get jobs.

Now, on to the articles.

1) There is a fantastic article in IHE this week about hiring at two year colleges by an English professor. It is the perfect complement to what I wrote some time ago about getting a job at a CC, and pretty much proves my thesis that science and humanities are looking for the same thing at the CC level. There is a huge overlap between the suggestions in that article and the ones in mine, and both emphasize the difference between applying at a CC and what is expected at other types of colleges and universities.

As he said, you must know what we do and what kind of students we have (particularly if you are going to teach composition or algebra or general education classes) if you hope to have any chance of getting a job at a CC. And I will add that I think one of the comments in that article is from someone totally ignorant of what we look for. Having been an adjunct at a CC is NOT the kiss of death. Quite the opposite. Just as med schools want students who have seen the pukey side of a hospital so they don't quit two years in when they discover they have to spend all of their time with sick people, CCs want to hire people who know exactly what they are going to be dealing with for the next 20 years.

2) There was also an earlier article (Part One on 'The Two-Year Option') where Hurley (an English prof at Diablo Valley College) goes into some detail about why he finds the CC environment such a good fit. Like him, I think I have a terrific job that is quite different from what I thought might be my career goal, and like him I find my students an interesting group.

3) For the back story about the job situation in the humanities, history, etc, check out these articles from IHE: History and English and links therein. To me, this is all deja-vu of the situation my older friends and colleagues faced about 40 years ago, as detailed here. Only they had it worse, because their job odds went from 90% to 1% in just a few years, and stayed very low for a decade. And if you read that article you will know why I find comments about Boomers offensive: that pipeline got blocked by the generation that earned a PhD when the first Boomers graduated from high school and stayed in those R1 faculty jobs for 40 years or more.

I think I left something out, but that will do for now.

UPDATED 16 January:

Thanks to Dr. Crazy's blog about bleak job prospects (which contains links to two other articles on that topic), I know remember that I left out Dean Dad's blog about why undergrads go on to graduate school when the job prospects are so poor.

4) Dean Dad wrote a great analysis saying that it is the loss of a clearly legible path to other careers that leads high achievers to pursue the mostly dead-end path to a PhD in the humanities. I can see that, because there is quite a bit of truth to it even in physics, and physics is a field where there are jobs that clearly use physics even if faculty and career advisers don't know about them. It is much less clear how you would get a job in industry with a history degree than with a physics degree.

5) And read what Dr. Crazy wrote from the English end of the world (linked above, as well as what it looked like to Tenured Radical and Historiann from the history side.

6) Sort of unrelated, sort of related, I just read Malcolm Gladwell's article in the January 18 issue of The New Yorker about entrepreneurs. (Only the abstract is available on-line, but it gives a really good summary of the article.) The thesis (drawn from descriptions of some very successful businessmen that, like Ted Turner, have usually been described as gamblers) is that SUCCESSFUL entrepreneurs go after the sure thing. The unsuccessful ones are the gamblers. Gambling on a faculty position in the humanities at an R1 or Ivy where you teach one small class a year for a six figure salary might fall into the latter category, because even a job at a CC or at a regional comprehensive (what Dr. Crazy describes) is far from a sure thing and FAR from the "life of the mind" those students are gambling on.

I'm really glad my niece did not go to graduate school.

Read Entire Article......

Friday, January 1, 2010

Happy New Year!

I Got It!
see more deMotivational Posters

Or see the original ones: from Despair, Inc.

I like the one that's new for 2010: Bailouts

But let's not overlook this one or the T shirts for social media and the big bank bailouts.

Read Entire Article......