


21 October 2015

"I didn't know how to do the problem, so I left it blank."

Image from
Yeah, in the first weeks of school I hear that a lot from 9th graders.  I get a real cross-section of 14-15 year old boys, the quality of whose middle school educations are all over the map.  These folks are generally good boys who care about doing well in school.

And that perception of "good" is actually an obstacle to teaching physics.  I recognize that universal, quality education is an American core value, one that I obviously share with most of the country.  I acknowledge that elementary and middle school teaching requires different skills and techniques than I regularly employ -- reading fluently, following directions, writing legibly, sitting still when required are all skills that I take for granted in my 9th graders, while they must be taught to 5th graders.  I mean, I know that most of my class will be less-than-accomplished at these basic skills; but I am confident that they have been previously taught and internalized.  It's my job to help the students execute these skills in the context of learning interesting and rigorous physics.

To me, a "good" student coming out of middle school is one who understands the basic procedures of how to learn.  That's not how my 9th grade boys seem to see the world, though.  To them, a "good" student gets the right answers.  Being wrong equates with moral failure.  Thus, they seek the right answer through any means necessary, including hangdog eyes and a submissive "but I just didn't know what to do, please help me."

The problem that I face is that too many of my students are used to the teacher feeding them answers in exchange for that puppy-dog-look.  I'm sure teachers don't think of what they're doing as feeding answers, but they are -- responding to a "clarifying" question, suggesting something to think about, or giving away the first step in an already-taught-process might allow the student to overcome a mental block.  But what's that student going to do on a test?  Well, the dirty little secret in so, so many high school classes is that the teacher does the same prompting during tests.  No wonder students have trouble with SAT and AP exams in which no help is available.

Now, before you go ballistic in the comment section about how cruel this Jacobs guy is, understand the context.  I will never, ever engage with a student who presents me with a blank paper and asks for help.  However, I will always and enthusiastically engage with a student who presents me with a serious written attempt at a solution.  

I explain this difference again and again to my classes.  Nevertheless, for weeks I face frustrated students who ask, "Well, can't you just tell me what wavelength means?  Can't you suggest which equation to use?  This problem makes no sense, can you explain what I'm supposed to do?  AArrgh!"  I respect the frustration.  They don't want to be wrong, 'cause that's the same as being bad.  And I'm not helping them be right, so I'm forcing them to be bad.  What a cruel, cruel man.

Since most of my students are athletes,* I often respond with a sports comparison.  "You're the goalkeeper for a penalty kick.  You don't know which way the opponent will shoot.  So... you stand there with your head down, and don't move because you're afraid to be wrong?!?"  (No sir, I pick a direction and dive.)

*for a given value of "athlete", anyway

Or, "You're the quarterback, and the defense lines up differently than  you expected.  So, you take the snap and stand there sadly, until you're sacked?!?" (No sir, I run somewhere, or make the best play I can.)

Or for the non-athlete: "You're in a play, and the other character in your scene drops an important prop.  So, you stop the show, hang your head, and walk off stage 'cause you don't know what to do?!?  (No, sir, I cover as best I can and continue with the scene.)

A blank problem is a sin.  A wrong answer is an opportunity to learn.  I have to hammer these facts of life over and over, for several weeks.  That means blank problems suffer enormous grade penalties, yes, but also they earn trips to special afternoon study hall, required extra help sessions, notes to advisors, and even notes to parents where necessary.  On the other hand, students learn quickly that the worst consequence of a wrong answer is the loss of a point.*  Thus, it's far more effort to leave things blank than it is to make a reasonable guess.

* They also learn quickly that the loss of a point is not relevant in the grand scheme of the universe.

You probably see how things go next: the students often discover that their answers are righter than they thought.  When the answers aren't right, they have context for my explanations -- not "oh, Mr. Jacobs said the wavelength is 2 m" but "oh, I almost had it, I just didn't realize that the wavelength had to be determined from the diagram."  The latter reaction is far more likely to result in correct answers in the future.

It's not about today's homework or test -- it's about long term understanding and performance.  That's the point that so many teachers miss.  We all want our students to do well, we all want positive feedback from students and parents.  But I want that feedback at year's end, when they experience for themselves just how confident and well prepared they are for their physics exam compared to all other exams.  I want that feedback from alumni, who universally describe not only how much fun my course was, but how well it prepared them for other academic endeavors.  

Right now, though?  I want them to write their best attempt at answering today's question.  And if they're wrong, well, they'll find that dungeons do NOT await, contrary to their conditioning.

05 October 2015

How I'm starting my 9th grade AP course -- position-time graphs

Juniors and seniors like to sit still and take notes while I talk from the front of the room.  Sure, they want to be entertained and impressed by quantitative demonstrations, but nevertheless they don't initially appreciate active, open-ended classes.  It takes considerable work over the course of the year to convince upperclassmen to relax enough to deal with true "inquiry."

Freshmen, on the other hand... they are thrilled NOT to have to sit still.  They're willing to try things that they might get wrong.  And they're not going to remember much that you say to them from the front of the room, anyway, so you might as well give them an open-ended class.

In order to act on these observations, I now begin my AP classes for seniors differently than I begin my AP classes for freshmen.

For seniors, I begin with equilibrium.  I do demonstrations with friction, normal force, objects hanging from strings at angles... for each, I show how to predict amounts of force using free body diagrams, then we verify the predictions with scales.  These are strong classes, allowing my students to quickly figure out how to solve complicated physics problems, setting the stage well for the year's material.

But for 9th grade, I'm starting with position-time graphs.  I'm doing the very same exercise I do with my regular conceptual physics course, but over one or two days rather than four or five days.  

I briefly demonstrate the use of the motion detector with the Vernier labquest.  I hand out just the facts on this sheet about position-time graphs.  (I'll hand out the other facts later.)  I give each student a copy of this worksheet, as shown at the top of this post:  It has a position-time graph, along with three questions about the physical manifestation of the graph.  Each student gets a different graph, which I draw in by hand.  Some represent constant speed motion, some represent speeding up or slowing down.

Each student answers the questions on the worksheet one at a time, bringing the answer to me after finishing each one.  I either say "good, move on to the next question," or I explain the mistake in reasoning and ask the student to try again.  

Once all three questions have been answered correctly, I send the student to the back of the room to do the experiment.  Ideally, in a few minutes he comes back to show me a labquest with a correct position-time graph displayed.  See: prediction and experiment, all together in one exercise.  

After each student has done two or three of these, I give out a similar worksheet and facts about velocity-time facts.  And so I can teach motion graphs in just a couple of days.

I tried this activity with seniors.  They didn't like it... they were angry with me when I said "no, sorry, that's not right."  Even when I sent them to the back to do the experiment, even when they came back with results that didn't match the graph, they sulked, as if it were my fault that the carts and sensors didn't adjust to their lawyerly interpretation of the laws of physics.   No, open-ended, independent class work with seniors was a bad idea at the start of the year.  It caused the students to hate me as a proxy for hating the world.

But the wide-eyed freshmen on their first day of an intimidating AP physics course?  They were thrilled to be doing something hard but manageable.  They loved seeing whether their predictions were right or wrong.  They loved the confidence built by revising their ideas until the experiment matched their prediction.  

People wonder why I want to teach AP Physics to freshmen... and this is why, in a nutshell.  My freshmen are wide-eyed puppies, still thrilled by discovery.  Despite the difficulties of structuring an AP course for younger and less-experienced students, the enthusiastic cooperation from my ninth graders compared to the sullen grade-gaming of too many of my seniors makes any amount of extra work worthwhile.