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2013 May 31

Cramming for the SAT2

Filed under: home school — gasstationwithoutpumps @ 01:48
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My son does not usually do test prep before taking a standardized test, nor does he usually cram for exams in classes.  As a general rule, our educational philosophy is to learn the material as one goes along, and let the tests reflect what was retained.  For previous exams (SAT, SAT2 Math Level 2, AP Physics C, AP Calculus AB, AP Computer Science, …), the amount of prep has usually consisted of going through one practice exam and looking to see if there is anything on that test he has forgotten or never learned.  If so, he did a little reading and maybe an exercise or two to cover the hole.

The one exception in the past has been the SAT writing section. Because of his problems with writer’s block, we did have his writing therapist work with him on timed essays similar to the SAT essays.  He believes that this did help him on the SAT, as he did not shut down for the essay as he might otherwise have done.

This weekend he plans to take 3 SAT2 exams: Physics, World History, and US History.  The Physics SAT2 is mainly for college entrance, as many admissions departments require at least 2 SAT2 tests, and pay no attention to the AP exams that test the same subjects deeper. The SAT2 tests in history are to satisfy the University of California a–g requirements, since the ways he learned (a course at home for World History and an unaccredited school course for US History) do not have the UC seal of approval.  If he gets at least a 540 in World History and a 550 in US History, he’ll satisfy UC that he has completed the “a” requirement in Social Sciences/History.  With what he has already done (in terms of tests and courses), this will complete his a–g requirements.  The SAT2 tests this weekend will also provide him with an alternative way to meet the UC entrance requirements: admission by exam, which he will meet if he gets a 580 or better on any of the 3 SAT2 tests—something he should be able to do very easily in physics.

He followed his usually practice for the physics test (looking over a practice test), found a couple of topics that we had not covered yet, and read the textbook or Wikipedia on those subjects.  For World History and US History, topics he has learned a little but not really cared much about, he is cramming—by reading (or re-rereading) Larry Gonick’s Cartoon History of the United States, Cartoon History of the Universe II, and Cartoon History of the Universe III.  Together with what he remembers from his courses, those should be enough to get him in the 600s or 700s—probably not an 800, but he doesn’t need that for the history SATs.

The SAT and AP tests are somewhat expensive—though much less so than most of the courses we’ve been paying for, adding only about 5% to the cost of his education.  Although some people justify the AP costs by the college tuition one can avoid with AP credit, most of the schools where my son would fit in give little or no credit for AP—they expect everyone to have had courses at that level and still need 4 years to complete the program at the college.  We’ve been justifying the expense of the courses as external validation for our home schooling, not as tuition avoidance.

On one of the home-school e-mail lists I’ve been on, the standardized tests have been characterized as “hoop jumping”: doing meaningless tasks simply to amuse those with the power to compel obedience.  While I feel that way to some extent about the Common Application and FAFSA paperwork (which I am dreading), I don’t have the same reaction to the standardized testing. The tests have a clear correspondence with what the colleges need to know about students when choosing whom to admit, and so are not meaningless tasks.  For home schoolers, they provide an external validation for the content and level of the courses that students have taken that is not otherwise available. They also represent one of the lowest stress ways to validate the courses—certainly much less effort than putting together a portfolio or taking a busywork-heavy accredited course.  Note: kids with test anxiety may not find our approach to be low stress—home schoolers have to match their educational strategies to the kids involved.

We have found that the UC a–g requirements and the California high school graduation requirements do involve a certain amount of arbitrariness—curricular choices that we would have made somewhat differently if we had had free rein.  For example, we would probably have reduced the English and social science requirements, replacing them with more science, math, computer science, robotics, engineering, linguistics, theater, technical writing, and foreign language.  Instead we sacrificed some of the useful stuff (foreign language, linguistics, engineering, and technical writing) in order to meet the letter of the requirements.  Even the physics course this year suffered from the lack of time imposed by trying to meet the high school unit requirements for English and history.  Next year will again waste a lot of time on not-very enjoyable English and social studies, just to meet the bureaucratic high school graduation requirements—time that would be better spent reading, writing, and studying university-level subjects.


2013 May 28

Snell’s Law lab

Filed under: home school — gasstationwithoutpumps @ 23:23
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We are way behind on physics—my son took the AP C: E&M test before we even got to Faraday’s Law.  He read through the last 3 chapters of Matter and Interactions in 3 days, rather than the 8 weeks we had originally planned, and he hasn’t done any of the exercises in those chapters yet.  Because he is planning to take the SAT 2 Physics test this Saturday, I decided that he should at least have a cursory familiarity with Snell’s Law.  Since there wasn’t time or energy for a problem set, we did a lab instead.

I had noticed when playing around with the violet (405nm) laser pointer, that the water in the fish tank fluoresced brightly.

Laser beam causing fluorescence of water in fish tank.  The blue is probably from bacterial cells in the water, and the red from chlorophyll from algae growing on the walls of the tank.

Laser beam causing fluorescence of water in fish tank. The beam comes in from the right and is reflected off the water-air interface.
The blue is probably from bacterial cells in the water, and the red from chlorophyll from algae growing on the walls of the tank.  We get the blue fluorescence even from water right out of the tap, though not as brightly.

We made some very crude measurements of the angle of the beam coming into the water and of the beam in the water using a protractor.  (The beam coming in was invisible in the air, so measuring the incoming angle was very inaccurate.)

Despite the very inaccurate measurements, my son got a decent estimate of the index of refraction of the water.  We don't know the true index of refraction, since the water has a lot of "stuff' in it.

Despite the very inaccurate measurements, my son got a decent estimate of the index of refraction of the water. We don’t know the true index of refraction, since the water has a lot of “stuff’ in it.

Here is the gnuplot script he used for fitting the data (with some editing by me, which he did not entirely approve of):

set angle degrees

set xrange [0:90]
set yrange [0:60]

set title 'Index of Refraction in a Fishtank'
set key top left
set xlabel 'normal angle in (degrees)'
set ylabel 'normal angle out (degrees)'

refract(a_in, rfr_ind) = asin(sin(a_in)/rfr_ind)

water_rfr = 1.333
fishtank_rfr = 1 # initial guess

fit refract(x, fishtank_rfr) 'snell1.gnudat' using (90-$1):(90-$2) via fishtank_rfr

plot 'snell1.gnudat' using (90-$1):(90-$2) title 'Measured', \
    refract(x, fishtank_rfr) title sprintf('Fitted %f', fishtank_rfr), \
    refract(x, water_rfr) title sprintf('Pure Water %.3f', water_rfr)

I’m sure that with more careful measurement, we could get much less scatter around the theoretical curve, but we were tired at the end of the day and couldn’t be bothered to do the measurements right.

2013 May 27

Sounds like my course

Filed under: Circuits course — gasstationwithoutpumps @ 19:53
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I’ve been reading an infrequent blog by a freshman at Olin Engineering, because it is one of the schools that my son is considering applying to.  He likes the idea of project-based learning, though he is more interested in computer science than in engineering, and Olin doesn’t have a straight CS option.

The post Burn Brilliant: Reflections on Second Semester, Part 2 describes a first-year course called Real-World Measurements:

The first half of RWM was formatted exactly like ModCon. It was centered around labs in which we used lots of different sensors. For example, we built an EKG, a circuit that could tell how far it was from a wall by sending and receiving sound signals, a strain gauge circuit to study beam bending, and a pulse oximeter. In lecture, we talked about op amps (in more detail than we had in ModCon), instrumentation amps, some more complicated filters, Bode plots, and Fourier series.

That sounds like it has a lot of overlap with my applied circuits course for bioengineers:  we also did an EKG and a strain-gauge circuit (though our strain gauge was in a pressure sensor not on a beam).  I considered doing a pulse oximeter, but I never figured out a way to calibrate the device—I wonder how the Olin students handled that.  If the pulse oximeter is doable as a one-week project, it would be worth adding to the course, even if something else is removed.

I should probably look for materials on the web about the course, or contact the instructor.

The Olin class was the second in a series, so they were able to go a bit further into sensor usage and electronics theory (we did Bode plots and simple RC filters, but not Fourier series), but the emphasis on sensors as the focus of a course is similar.  The Olin course had a second half that was more student-directed group project (part of the pedagogic approach at Olin that is so appealing for engineers), which I don’t think there is room for in my applied circuits course.

Large independent projects provide a lot of learning, but are a bit slower than more focused design exercises. Having only 10 weeks for the whole course limits how much time can be spent on projects. I can’t assume that students will pick up more material in subsequent engineering courses, since this is the last electronics course that most of them will take, so I made the tradeoff of doing more design exercises, but somewhat smaller ones.

2013 May 25

Credit card identity theft

Filed under: Uncategorized — gasstationwithoutpumps @ 17:19
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This week I got the following message:

May 23, 2013

Dear Patron:

We regret to inform you that on April 25, 2013, Vendini, Inc. detected an unauthorized intrusion into its systems.  Vendini provides box-office and online ticketing services to hundreds of entertainment venues, which include tour, casino, sports, and arts organizations across the U.S. and Canada. Based on our records, you used a credit card to make a purchase for an event that was processed through Vendini’s service, and your information may have been involved in this incident.

We are actively cooperating with federal law enforcement, and this notification to you was delayed specifically to support law enforcement’s investigation.  In addition, a full-scale, internal investigation is under way at Vendini with outside computer forensic and cyber security experts.  Although our internal investigation is ongoing, we believe that in late March, a third-party criminal actor used hacking technologies to access our databases and may have accessed your personal information, such as name, mailing address, email address, phone number, and credit card numbers and expiration dates. We do not collect credit card security access codes (e.g., CVV, CVV2, PINs), social security numbers, usernames or passwords.

It seems to me that taking a month to notify users of a security breach is really bad practice—it was unlikely to provide any extra forensic information, and left customers vulnerable for a really long time.  In fact, I think that they were also slow to recognize the breach (which they now think happened in March).  Amazon had notified me days earlier of an apparent identity theft:

Apr 19
Greetings from

We perform routine reviews of orders to protect our customers. During one of these reviews we discovered that an account was opened with a card used by you on another account. For your reference the card in question is a VISA.

As it appears the card was used without your authorization, we have closed this new account and cancelled any outstanding orders. If the account is indeed yours, we apologize for any inconvenience caused and ask that you notify us as soon as possible by replying to this message.

If the card was used without your authorization, we recommend you cancel the card immediately by contacting the financial institution that issued the card.

You should review all recent charges made to this card, reporting any unauthorized charges to your financial institution. The financial institution, in turn, will send you forms to formally dispute the unauthorized charges, the applicable merchants will be notified and charged back, and your account subsequently credited.

Although we are not permitted to provide you with any details about the unauthorized use, we will provide this information to any law enforcement agency investigating this matter.

I was pleased that Amazon had notified me of the potential identity theft, but a bit annoyed that they paid one of the clearly fraudulent charges (which was the same as the earlier one that had triggered the fraud alert, despite their claim that they had cancelled all outstanding orders).  I challenged the charge through the credit card company, and I expect that it will be resolved without problems.
One irritating “feature” of the Citicard system is that you can only challenge charges after they have been paid—they have no way of flagging an “approved” but unpaid charge as fraudulent, so even after I had talked with the Citicard customer service people, and identified the fraudulent charges, I had to monitor the account daily for over a week, waiting for them to pay the fraudulent charge so that I could challenge it.  Given how common security breaches and identity theft are, you’d think that they would have a way of marking pending transactions as probably fraudulent, and not have to wait until the transaction has been completed to challenge it.
I had, of course, cancelled the card and gotten a new one (a bit inconvenient, as I had three recurring charges billed to that card) long before Vendini bothered to inform me of the breach.  Needless to say, I will think twice about ordering tickets through Vendini ever again, as they are clearly incompetent at handling credit card security both before and after breaches.  My unwillingness to trust Vendini with my credit card info may mean not going to any shows at Cabrillo College unless they change ticket vendors.

2013 May 24

Learning from theater

Filed under: Uncategorized — gasstationwithoutpumps @ 22:31
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I’ve been thinking about Mark Guzdial’s post from about a month ago, Learning about learning in a musical: The power of deliberate practice in a whole setting.

I could go on and on. A prop is missing, a costume breaks, someone flubs their line or doesn’t get on stage quick enough. Things happen, and people have to think on their feet. Let’s compare this to introductory computer science class, where students famously have difficulty figuring out one way to do something in 10–15 weeks of practice. Or when they do something the one way that they can figure out, it just barely works and the code is frequently awful — ugly and hard to read.

How did everyone involved in the musical learn so much, so well, in such a short amount of time? And why doesn’t that happen so often in formal education?

I have noticed the same thing in theater classes that my son is involved in (though he doesn’t do musicals)—that there is often a high level of performance and flexible response to problems after very short preparation time.  I’ve seen plays in which one of the lead actors breaks an arm between the Saturday and Sunday shows, and one of the tech crew takes over the role, despite never having studied the script—and does well with it.

Most of the productions my son has been in have very tight schedules: usually 20–30 hours of rehearsal  total before the production.  In some classes, the kids didn’t even get the full script until 2 days before the production.  Yet they coped with the challenges and performed at a high level.  When a line was flubbed or a cue missed, the other actors covered and recovered—sometimes with only a few in the audience realizing that there had been a miscue.  (The teen ensemble is very good at this—especially since many of them are in an improv troupe together—but even 9- and 10-year-olds can do it.)

Of course, it isn’t always that way.  There was one performance of Midsummer Night’s Dream that is memorable for the sheer awfulness.  The students had supposedly been working on it for an entire semester, but only two of them were off book (my son, as Puck, was one of them) and most did not know their blocking and mumbled their lines.  One of the best moments of the play turned out to be an improvisation—they’d never bothered to make (or even think about) a prop or costume for Bottom’s transformation, so as the actor entered he grabbed a pair of Uggs that had been left beside the  stage and used them for Bottom’s donkey ears.  The whole performance was comparable to Mark’s comment about typical student code: “Or when they do something the one way that they can figure out, it just barely works and the code is frequently awful—ugly and hard to read.”

What was the difference between that awful production and the 30 or more good ones my son has been in?  Does an answer to that question address Mark’s questions: “How did everyone involved in the musical learn so much, so well, in such a short amount of time? And why doesn’t that happen so often in formal education?”

One difference was that the awful production was a private school class, and the good productions were after-school or summer classes that parents had to pay money to register their students in.  Many of the students in the school class were just there to satisfy an arts requirement with the minimum of effort, while almost all the kids in the other productions had begged their parents to let them do the class.  Kids doing something because they love it perform at much higher levels than kids looking for minimal-effort passes.  Having a part with a lot of lines is desirable for the actors by choice, so they make an extra effort at learning lines, in order to get meatier parts in future productions.  Having lots of lines to learn is not desirable for those trying to get a minimal pass, and they make no effort.

Parental support for the kids’ learning is also much higher with the opt-in courses: the parents had chosen to invest specifically in the theater class for their kids, and so were very willing to take the time to make sure that the kids ran their lines every night.  Parents who sent their kids off to private school often felt that they had done their job by paying the (high) tuition, and everything else was up to the school to handle.

Another important point is that many of the kids in the school play had never acted before and did not realize how much work a good production takes.  They thought that they could fake their way through it with minimum effort, the way they did in many of their academic classes.  In the after-school and summer theater classes, the majority of the students had done one or more productions previously with the same director and could set a good example for the newer students.  The culture of “good enough” is common in schools, but not so common among aspiring actors.

The adult supervision of the courses was also quite different: the director for the awful Midsummer Night’s Dream was changed in middle due to illness, and there wasn’t a clean transition. (Note: the drama club at the same school, with the same director, the same year, put on an excellent production, and so I think that the biggest differences were in the students, not the adults.)

So what does this all say about CS education?

Mark Guzdial quotes Anders Ericsson:

 I am suggesting that Ericsson’s conditions for developing expertise are present here: “The most cited condition concerns the subjects’ motivation to attend to the task and exert effort to improve their performance. The subjects should receive immediate informative feedback and knowledge of results of their performance. The subjects should repeatedly perform the same or similar tasks.”

Motivation was the big difference I saw between the successful and the unsuccessful plays (even first-time-on-stage kids often do quite well), but it is certainly the case that the students get a lot of feedback as well, generally very shortly after each run-through of a scene.  The kids do repeatedly run each scene, though nowhere near the number of repetitions that Ericsson believes is necessary.

Mark also says

The actors and stagehands in a musical know where we’re going.  We have a complete picture of the role of each piece.  We know what a good show looks like.  We focus on this number here, and this set change there, but there’s no question that everything is supposed to fit together.  It’s not like “We’re learning recursion, and I’m not sure why I’d ever want to do this.”  Students in formal education often don’t understand the relevance of what they’re learning, of how it all fits together.

I’m not so sure that the actors know where they’re going the whole time.  They know generically what a good show looks like, but they don’t know how any particular play is going to come together—at least not in the 2-week classes my son has mostly taken.  The directors and the actors are usually still tinkering with the blocking and lighting an hour before the show opens.  I’ve seen substantial changes between a Friday show and the Saturday show.

I don’t think a highly structured knowledge of the endpoint is what makes the group work of theater so productive—quite the opposite.  I think that willingness to experiment and to keep trying to improve even after it is “good enough” is more important.

I also think that group work of theater, where everyone has to do their part for the whole thing to succeed, is very different from the group work of school, which is almost always make-work that takes a job best done by one person and makes it harder by requiring multiple people to work on it at once. In theater, the production nearly always requires many actors and a tech crew—people have to work together to get anything done.

Everyone in the theater is focused on the same goal—making a great production—and they are all willing to work hard on achieving that goal, even if no one notices what they have done individually.  It is very, very rare that any school project gets that level of commitment (I’ve seen it occasionally in engineering project courses, when the students really want their project to excel and the goal itself is exciting to them).

I’ve yet to see a first programming course in which assignments really gripped all the students, and I’ve never seen one in which multiple people on a team worked any better or faster than the best person on the team working alone.  The problems that can be given in a first programming class are simply too small for team work.

Another difference between CS classes and theater classes is that the CS classes often try to provide uniform outcomes: everyone in the class will be able to use certain language constructs or data structures, or understand certain key concepts.  Theater classes tend to take in students with a wide range of prior training and skills (from first time on stage to 12 years of experience in some of the classes my son has been in) and provide some growth for each student. It may be that no two students in the class come out learning the same skills. One may be working on better voice projection, another on learning longer lines, another on stage combat, another physical comedy, another how to walk in high heels, … .  The teacher’s goal is to use everyone’s strengths and build on them to produce both a pleasing shared product and useful learning for each student.

I don’t have a prescription for taking pedagogy that is successful in theater and converting it into pedagogy that is successful in CS.  The goals of the courses and the modes of working are different enough that I’m not sure that there is much overlap in what pedagogy works.  One thing that is true of both theater and CS  is that passion for the subject and diligent practice go a long way towards improving performance.

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