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17 April 2015

Lessons from a year of teaching AP Physics 1, part 1: "diving in"

And now for a series of posts reflecting on a year of teaching AP Physics 1.  I've already posted a bunch of stuff that worked well; but a good scientist publishes the results of all experiments.  

Part 1: Should you "dive in" to the AP Physics 1 expectations for verbal response?

When I wrote the 5 Steps to a 5 Teacher's Manual, my intent was to begin the year with essentially my well-received and well-practiced AP Physics B course.  I had always covered mechanics before the first trimester exam in November. I intended to cover waves and circuits in December.  This coverage would be equivalent to what I did in physics B, with plenty of calculation, but also some "justify your answer" questions and laboratory work.

Then, in January, I intended to start over from the beginning of the course, with deeper discussions of all topics.  This is when I would introduce multiple representations of energy and momentum, when I would ask essay-style open-ended questions, when I would do unguided laboratory work.  Rotation would come in February and March, as a review of all of the mechanics topics previously covered twice.  I know from long experience that the best way to learn physics is to see the same material several times, separated by months; so that's how I set up my class.

But I got some bad advice.  And I took the bad advice.  D'oh.

At an AP consultant meeting in April of 2014, I mentioned my plans during an open discussion of teaching ideas for the new course.  I was set upon by this room of physics teachers: "You shouldn't ever do that, let alone recommend it."  "You must teach the deeper expectations of the new course from the beginning."  "This course absolutely must be inquiry-based from day 1."

Now, these people who were attacking my idea were people I know and trust: excellent physics teachers with significant experience, and with serious understanding of the new AP Physics 1 curriculum.  I had twenty respected physics teachers telling me, in so many words, that I was being an idiot and setting my students up for failure.  I'm used to ignoring well-meaning but dumb advice from teachers who aren't familiar with my subject or with me; however, when some of the most-skilled people in my profession were telling me I'm wrong, I'd have been arrogant to dismiss their concerns out of hand.  

The argument that finally carried the day with me threw my own advice back in my face:  "Start the course with AP expectations, don't ease into AP expectations.  If you start with calculational physics, and if students have success and good grades with calculational physics, then most will not be willing or able to adapt later to the deeper and harder expectations for conceptual and descriptive physics."  I've always told teachers to dive straight in to physics when teaching upperclassmen, and not to pussyfoot around difficult topics.  Students need to know from day 1 the level of the course.  By day 45 they, invariably, have adapted to the expectations, such that the rest of the year and the AP exam are just more days at the office.  

So I did what my colleagues suggested, against my own better judgment.  I dived in, with every problem set requiring significant verbal response, with all test questions going deeper than mere calculation.

And it didn't work.  I was right with my first idea.  I set a poor tone for the class, and I paid the price.

What were these AP consultants on about, then?  What did they miss?

Primarily, I think my colleagues weren't familiar enough with what I mean by calculational physics.  I have never, ever taught physics as a math course, in which students hunt for the right numbers to plug in to the right equations.  My students were so successful in AP Physics B precisely because I integrated conceptual understanding, verbal justification, and an understanding of the physical meaning of numerical answers into a calculational course.  They didn't realize how close my AP Physics B course was already to a good AP Physics 1 course.

In the first few months of this school year, I and my students struggled mightily.  The weaker students felt that everything was over their heads.  The stronger students argued with me about whether their writing communicated what they thought it did.  Problems and activities took way longer than I had budgeted, because writing about anything takes a long time; writing about physics without a solid calculational background takes even longer.

What if I had gone with the calculational approach at the beginning?  The fact is, students come to me answer-focused.  It is my job to make them process-focused by year's end, but I can't change their mindset instantly.  One advantage of calculational physics is that a calculation is right or wrong -- it makes a correct, experimentally testable prediction, or it does not.  My class used to stop arguing with me about points and grades very quickly, because it's hard to argue with "do the experiment, and if it gives the value you predicted I'll give you credit."  

A second advantage of starting with calculational physics is that weaker students -- folks who can pass the AP exam at year's end, but who will be significantly challenged the whole way -- can find some early success.  No, the AP exam will not award much credit at all for getting the numerical answer to a kinematics problem right.  But please don't underestimate how difficult even algebraic kinematics is for many students.  I used to hear regular feedback during our April review in the style of, "wow, remember when a problem like this was so, so difficult?  I wonder why I found it so hard, I get it now."  A good number of students need to play with equations and numbers, to work on the skill of plugging into equations until they're comfortable recognizing known and unknown variables in a relevant equation.  I denied my class the opportunity to experience success and earn credit for their learning process; and so my weaker students because hostile as they felt more and more overwhelmed.

Could I have avoided the hostility?  Not entirely...  physics ain't easy, and every year I've had at least some seniors initially angry at me*.  But with a more appropriate start to my course, weak students could have felt like they were getting somewhere, because they would have gotten some right answers.   Then they would have gradually come to the same understanding of physics that they've obtained anyway.  Ideally, the grousing fades into background noise as the class realizes, student by student, how well they're understanding physics, and how intrinsically exciting physics is.  That process took seven months this year; had I started the year MY WAY, I suspect that I could have reduced that to one or two months, just like I did for years in AP Physics B.

* Why angry?  Angry because they're working hard and not getting A's, angry because they perceive that I'm reducing their chances of going to Harvard, angry because I collect and grade their homework every night (even though I don't assign a lot compared to most physics teachers), angry because my class is the first time they've ever NOT understood something instantly, angry because they're 17 year old boys... take your pick.  They almost always get over their anger by year's end.

1 comment:

  1. Do you have a semi-detailed course outline that shows this calculational physics first method approach for AP 1? thanks

    ReplyDelete