23 August 2010

Mail Time: First test in AP physics B

Michael Gray teaches in Georgia, where school starts the first week of August.  I guess they figure that since they have to run the air conditioning 11 months a year anyway, they might as well start school early.  He writes:

I have gone through Equilibrium and Free Body Diagrams, Torque and 1-Dimensional Kinematics with my AP Physics B students. I want to give them a test this Wednesday. I was thinking of giving them ~15min of multiple choice and 25-30min of Free Response in our 50min period. Does this sound like a good plan? Or would you do all MC or all FR for each test?

Also, should I let them use the formula sheet? When are they allowed to use calculator?
 
Michael attended my AP Summer Institute at Kennesaw State University a month or so ago.  He knows my general advice to AP teachers -- give all tests in authentic AP style, even using authentic questions from past exams where possible.  I'd say the same thing to all those who teach toward a high-stakes, cumulative exam, such as the Regents, IB, or whatever.  Classroom tests should be identical in form, content, and degree-of-difficulty to the final exam.
 
Second question first:  The AP exam allows the "constant sheet" for both multiple choice and free response sections.  AP allows a calculator and formula sheet for the free response only.  Therefore, I always do the same on my classroom tests.
 
Getting the mix of free response and multiple choice right is difficult.  Michael's difficulty is that he has only 50 minute periods every day.  I have an 85-minute lab period once a week, meaning that I can give a nearly half-length AP exam with both kinds of questions in that time.  (The actual AP exam is 180 minutes.)  It's trickier with the short periods. 
 
Later in the year, I might give a full 50 minute multiple choice test, knowing that my next test a few weeks later would be 50 minutes, all free response.  But on the first test, I think it's important for the students to get the feel for both types of questions, and to have the opportunity to show their knowledge on as many types of questions as possible.
 
The AP free response rule-of-thumb is one minute per point, or thereabouts. And, AP multiple choice is designed with 70 questions in 90 minutes.  The multiple choice and free response are weighted equally, since students spend the same amount of time on each.  Whatever option Michael chooses for his tests, I encourage him to stick to these time and score frames.  AP students need to get used to the time allotted for the exam.

I had two recommendations for Michael, neither of which is ideal with his short periods, but either of which will work.  For that first test, he might give an entire half-length AP over two days.  For example, Thursday's class would be 45 minutes, 35 multiple choice questions.  Then on Friday he would give 45 points worth of free response in that class period.  The sections would be combined into one test, graded on the AP scale.
 
The other possibility if he prefers a single test day is to give, say, 15 minutes for 12 multiple choice questions; then 2 or 3 free response questions equalling 30 points.  In this case, the multiple choice would be weighted to be 1/3 of the total test grade, because students spent only 1/3 of the test time on multiple choice.
 
Good luck to Michael, and to all who are trying to design AP-style tests.  It took me hours and hours my first year teaching to write my tests.  Of course, that was in the days before easy PDF scanning.  I had to recreate every diagram in microsoft draw 1.01.  Nowadays, we have authentic old tests available in microsoft word format, and I just cut and paste.  Plus, a diagram can be inserted in less than a minute by scanning, copying, and pasting.  I think I started teaching 15 years too early.
 
GCJ

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