Senin, 08 Oktober 2012

Questions about AP Physics 1 and 2

Georgia teacher Mark DiBois sends in the questions that virtually everyone in the country who teaches AP Physics B is dying to have answered:

Just read the e-mail about the sweeping changes coming in AP Physics B.  Now its going to be Physics 1 and Physics 2.

Yup, this has been in the works for a while, now.  The College Board has set a date:  May 2014 will be the last AP Physics B exam, and the new exams will be released in May 2015.

Can you fill me in on what the premise behind this is?

Take a look at this post from 2010 and this post from 2011.  Then look at the official College Board home page for AP Physics B and click on the redesign link.

Then take a look at the "curriculum framework", which has now been released publicly.

I read the curriculum and It didn't make a lot of sense to me.

I know.  That's the glaring weakness in the College Board's well-intentioned, and generally quite successful, effort to take Physics B ever farther away from the show-me-your-algebra-skills content of the 1980s and into the era of explaining physics with words.  Once the education PhDs got themselves involved, all hope of a one-page topic listing vanished.  In the effort to be transparent and specific about the exam, the College Board instead has written an impenetrable document, one that must be parsed as carefully as the infield fly rule.*

*Which, as TBS announcers showed during the Braves-Cardinals game, is incomprehensible even to purported baseball experts.  Don't get me started on that one.  Suffice it to say that Sam Holbrook got the call exactly right, and the TBS booth should be disbanded on grounds of competence.

The best bet is to learn over the next few years how to use a low-pass filter to eliminate the buzzwords, the eduspeak, and the myriad "the student can engage in...." fluff.

Take a look at the example questions on page 131 of the curriculum framework.  Read them.  Be sure you can solve them.  Don't bother with the "targeted learning objectives" -- just read the questions, and look for patterns indicating how this test will be different from Physics B.  For example:

  • See the ranking task: not "what is the power dissipated by the 110-ohm resistor," but "rank the energy dissipated by each resistor in a fixed time."
  • It doesn't ask, "calculate the initial speed of the car," but rather "can the speed of the car be determined, and why or why not?"
  • Not "at what time on the v-t graph is the cart at rest," but "describe in words the motion of the marble represented in the graphs above."
  • Note the request in the free response question to "justify your answer qualitatively, with no equations or calculations."  [my emphasis.]

What's going to come out of all the blabber is a course which demands that students be able to express a clear understanding of physics topics using WORDS.  

Now, that doesn't mean you should stop teaching calculational physics!  My own perspective is that for AP-level students, calculation is a step toward serious conceptual understanding expressed verbally.  If they can explain correctly, they can calculate, too; but if they can't calculate, they can't explain, either.  You're going to have to spend the time to go beyond just complicated problem solving, and into making the students explain why they solved problems the way they did.  Good physics B teachers are already doing this, but are pressed for time.  How nice that the new exams aren't as broad as Physics B.

What will be the basic topics for each?

Look on page 152 for Physics 1, and on page 160 for Physics 2.  This gives the "concepts at a glance."  It's still way too much information for a quick overview; but it's a start.  Perhaps eventually I will try to digest the topics down to a one-page cheat sheet.  You need that cheat sheet -- as long as you understand the level of deep verbal reasoning required in each topic.

If each course is a year long... do you have to take both courses to get 1 college credit?

Ach, the old credit question.  It's a reasonable question, but it's as answerable as "what is the sound of one hand clapping."  My answer: who knows.  Don't ever believe anything you hear about AP credit or placement policies unless it is in a personal communication with the registrar of the college you are considering.  

The best advice for our students: take AP Physics 1 as a first-time physics course.  That's how it's intended.  Do well on the exam.  Then, if you have a year of high school left, take AP Physics 2 or AP physics C.  Don't worry about college credit until you're at college.    

The best advice for teachers is to place your top first-year physics students into AP Physics 1.  Then offer either AP Physics 2 or AP Physics C as a second-year course, depending on your interest, and on whether your students are sophisticated mathematically.  (Physics 2 does not require calculus or any math higher than Algebra I / geometry; Physics C requires fluency at college-level calculus.)

These are good courses, courses that I encourage everyone to try before dishing out the boilerplate "Aarrgh, change!" complaints.  Every day, we ask our students to adjust to new ways of thinking in order to tackle new and scary physics problems.  I think it only fair that we make the effort to jump into a new course that requires us to change the emphasis of our teaching a bit.  Right?


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