Rabu, 07 Maret 2012

I'm teaching ninth grade conceptual physics next year.

Yes, we will use the Hewitt
book for ninth grade
conceptual physics.
I've spent the last few years getting my school's upper level physics classes in shape.  I now have a skeleton of problem sets, quizzes, labs, and tests that my colleagues can use to teach 11th-12th grade general physics, honors physics, and AP physics B or C.  The general physics course is based loosely on the New York Regents curriculum; the honors physics course on my version of what a future AP physics 1 test might look like.

So now it's time to tackle the only level of physics that I've never taught (cue ominous music): Ninth Grade Conceptual Physics.

(As an aside, I *have* taught ninth grade.  Once.  My first year of teaching.  "Integrated Science."  At a fluffy school.  Team teaching with an idiot who denied the results of experiment, who undermined me to students and administrators at every opportunity.  The scars still give a wee twinge on rainy days.)

The juniors and seniors I've worked with for years enter the school year as reasonably mature students; it's been my job to provide them with a challenging course to which they can apply their well-developed study skills.  Upper level physics can almost be thought of as a master class -- here's where all of the math, organization, relationships with classmates, writing, all of everything you've ever done as a student must be used in combination to conquer a difficult but manageable subject.

I am well aware that ninth grade is a different boat of gravy altogether.  I've begun talking to some of my school's best ninth grade teachers, listening to their thoughts and ideas of how they structure their course, how they develop relationships with 14 year olds, what different types of issues I can expect once I start teaching an entirely new species.  

One overriding goal over the next two or three years is to develop my own version of a ninth grade conceptual physics course, complete with a course structure, problem sets, laboratory activities, quizzes, tests, etc.  In terms of the level of physics, I want to aim at a low-arithmetic adaption of Regents-style questions, as I explain in this post.  Some of the course structure ideas that I know I'm going to implement:

Pace of the course:  I need to invert my usual approach.  With seniors, I've got to shoehorn in as much material as possible in the first half of the year.  That's when they're still motivated by their grade, that's when they are still afraid that any slackage might lead to the world ending and having to go to (gulp!) a different college than their first choice.  In the spring, I get some work out of seniors by demanding less.  They feel like I'm legitimizing their senior slide, so they actually do the minimum amount of work that I ask of them without complaint.  Thus, I'm always pushing the pace in the fall, and tapering through the spring.

With freshmen, I recognize that the fall is NOT the time to push hard in physics.  Adjusting to high school, and in my case to boarding school, is a difficult process for an adolescent.  Sure, a few students are ready for serious academics from day one -- these folks will be siphoned into Honors Physics within a few weeks.  Most need a gentle introduction to high school.  Then, in February or so (just as the seniors start to slack), freshmen are ready to move fast.

Sequence of coverage:  It's been argued that a physics class can seem friendlier by starting with more straightforward topics like ray optics.  At the AP level, I completely disagree -- the last thing I want to do is to give the immediate impression that memorizing facts alone will lead to physics success.  I want to start tough and get easier.

But in ninth grade, we will start with ray optics.  Refraction, total internal reflection, lenses, and mirrors all can be taught well diagrammatically and conceptually, with absolutely no mathematics.  But, I can use Snell's Law and the thin lens equation as an "application" for the honors course -- students who *can* handle quantitative predictions with these equations can be moved out, while the remaining students learned some serious physics without feeling bowled over by mathematics.  

I haven't decided on a precise sequence of coverage, but I do know that we want to gradually add arithmetic and basic algebra as the year progresses.  By the end we will certainly have covered the "Big Three" skills of reasoning with equations, interpreting graphs, and understanding the meaning of numbers.  It's just that we'll get to these skills gradually, after we start with a topic that allows straightforward conceptual prediction and straightforward experimental verification.

Types of test questions: I talked extensively to Bruce Oldaker, who at one time was in charge of helping the physics department at West Point streamline their testing at all levels.  He put into words a point about test construction that I have always done by feel:

First consider the portion of a test that is essentially recall, asking students to state facts or solve simple problems in situations they've seen before.  Then consider the portion of the test that asks students to synthesize multiple concepts, to extend problem solving techniques to new situations.  By sorting test items into bins of "recall" and "synthesis," it's possible to control the perceived difficulty of the test while adjusting the rigor of the evaluation of the students' physics knowledge and ability.

Now, as a long-time AP teacher, I have always advocated (though I didn't say it this way) keeping the "recall" and "synthesis" portion of a test consistent throughout the year, and in similar proportion to what students will see on the cumulative national exam.    Sure, that makes the first test of the year seem difficult; but soon enough students are old pros at physics tests involving considerable synthesis.  The shock of a test that doesn't just present homework problems with the numbers changed is going to happen sometime in the year; so, I say, deal with the shock right away when the class has plenty of time to recover.

Freshmen, though, need to build up to "synthesis" testing gradually.  Bruce and some of my colleagues point out that the same students who can't do anything but spit back facts at the beginning of the year will often develop their reasoning skills so that they can handle difficult questions by June.  Freshmen are growing that much physically and intellectually.  So, Bruce suggests that early tests be as much as 80%-90% recall... and that by the end of the year the recall percentage can be reduced to 40%-60%.  Without wasting too much time on meta-analysis, I'm going to be conscious of starting simple, and adding complexity to my tests throughout the year.

Got any ideas?  I'd love to hear 'em.  I've got an enormous amount of work to do to develop the freshman course to my liking.  It will take several years, and it will take plenty of failed attempts, too.  Maybe in a couple of summers I can hold a "Conceptual Physics Summer Institute" where we all get together to talk about teaching freshmen...


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