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05 December 2019

Can conceptual students learn calculational methods? Yes. Look at this voltage problem.

On the conceptual physics trimester exam, I showed the circuit above, then asked, "estimate the voltage across the 10 ohm resistor."

In conceptual physics, we teach, well, conceptual approaches to all problems.  That doesn't mean we never use equations or calculations, of course; it's just that even when a problem does require mathematics, students are generally required to explain an aspect of the mathematics in words.

For example, we teach students to approach this particular circuit problem with an equation:

* The current in each resistor is the same - that's a fact that "series resistors take the same current"
* Mathematically by V = IR, then, with the same I the bigger takes more voltage V.
* The voltage across series resistor adds to the total.  So the 10 ohm resistor takes less than 18 V, but more voltage than the 5 ohm resistor.

With this reasoning, we accept *any* answer more than 9 V and less than 18 V.

In class, the students each conduct this kind of estimation, then set up the circuit on a breadboard.  They find out experimentally that the voltages are in fact 12 V and 6 V.  After a bunch of similar predictions and experiments, my 9th graders develop for themselves an instinct - in series resistors, the bigger resistor takes more voltage, and the bigger the difference in resistances the bigger the difference in voltages.  That's not written down anywhere, 'cause it's not exactly rigorous.  But these conceptual students can estimate voltages for series resistors better than most seniors can calculate them.

Greg, when your students get to college, they'll be asked to calculate precise voltages.  I know you love conceptual physics, but the vast majority of college physics courses are calculational in nature. Aren't you doing a disservice to your students by teaching physics in a manner so different from how they’ll be asked to learn in their future?

Before I address this (legitimate!) concern on its merits, I’ll point out that it is emphatically NOT my job as a high school teacher to “prepare students for college.”  I provide for my students what they need right now… not what they should’ve had in the past, not what they may possibly need at some ill-defined point in the future. (But in Zen-like fashion, even though I adhere zealously to this philosophy, I've nevertheless received overwhelming feedback that, four years out, my students feel extraordinarily well prepared for college and college physics.  Go figure.)

I have plenty of anecdotal evidence that those who start their study of physics primarily with concepts (rather than primarily with calculation) retain more and deeper knowledge, and perform better if they continue to another physics class.  If you want them, I know you can find academic-style research studies that say the same thing.  But let's talk about just last month's trimester exam. and just this question.

Remember, I did not ever teach, model, demand, suggest, hint, or advise students about a caclulational method to finding the voltage across each resistor.  Not once.  We did sometimes ask students to calculate equivalent resistance of series resistors by adding the resistor values.  We did sometimes ask students to calculate the current through each resistor, using the fact that says "In ohm's law, use the voltage of the battery with the equivalent resistance of the circuit."  But voltages across series resistors?  Conceptual students were only taught how to make an estimate.

Nevertheless.  On this exam problem... a large majority of the class made a correct numerical calculation!


Without prompting, so many students calculated the current by using the 18 V battery with the 15 ohm equivalent resistance to get either 1.2 A (or "6/5 A" because they had no calculator).  Then, they recognized - usually wrote out in words! - that the current in the 10 ohm resistor is also 1.2 A because it's a fact that series resistors take the same current that's equal to the total current.  And finally, they used ohm's law across the 10 ohm resistor to get (10 ohms)*(1.2 A) = 12 V.


In other words... when the class had only, exclusively been instructed on a conceptual approach, they nevertheless figured out for themselves a useful calculational approach.  And they did so in a few moments, under the pressure of an exam.  I'd say 3/4 of my class did this, and 9/10 of those who tried it did it right.

So am I doing a disservice to students by teaching them conceptual approaches?  Nope... they can learn how to calculate without difficulty.  They don't even have to be carefully taught.

01 December 2019

Don't present work = force * distance right away. Start with energy bar charts.

I've been using annotated energy bar charts to good effect for many years now.  They force students to define a system and to identify what forms of energy are present in that system before they consider the end goal of a problem.  In this manner they serve the same purpose as free body diagrams for Newton's Second Law problems - I don't care what you're supposed to solve for, draw the free body or the energy bar chart first, and then you'll be able to solve or explain any aspect of the problem.  These devices make problem solving about physics understanding, steering the process away from a game of "let's plug some numbers in to some equations and do some algebra to get the desired answer."

But I'd always been hung up on the definition of "work."  See, students can come to an operational definition of potential energies (both spring and gravitational) and kinetic energies just through their equations.  It's simple for a first-year student to see that gravitational energy must be included in the bar chart when an object has a height above the lowest point.  "Because PE = mgh and h is not zero" is a good enough reasoning for now.  Similarly for kinetic energy: "The cart has KE because it's moving, so it has a v in KE = (1/2)mv2."  Work isn't so simple.

Work can't be understood simply from the equation "W = Fd."  Students must understand the idea of a force being parallel or antiparallel to a displacement.  The scalar nature of work.  The meaning of negative work.  That this equation only applies when a force is steady.  The difference between net work and work done by an individual force.

Until this year, I'd always spent part of a class defining work, and giving examples of when work done by various forces is positive, negative, or zero.  I showed how the net work on an object is the (scalar) sum of the work done by all forces; or, how net work done on an object is just force times distance, where "force" is the net force.   Then we did a couple of problems for practice.

And every year, I came up against the corollary to Rule Two of teaching.

  • Rule Two: Your students don't listen to you.  That's okay, they don't listen to me, either.  
  • Corollary: Nevertheless, students have sharp and selective recall of what you say when it provides maximum inconvenience.
I always hoped and expected that, as we moved to energy bar charts, students would adapt to using "W = Fd" as the same sort of operational definition as "PE = mgh," only with complications that we'd discussed at the outset about the meaning of work.  

Well.  My class certainly did remember W = Fd.  As an equation to be applied with brute force in any and all situations, to the exclusion of the energy bar chart.  Which stinks, 'cause the vast majority of problems which ask "how much work is done..." should be solved by finding the difference in total energy at two positions - that is, using an energy bar chart, not the equation W = Fd.

I turned the tide this year - by ELIMINATING the discussion of the definition of work.

Yeah, that's counterintuitive, isn't it... but that's how so much of teaching works.  More often than not, the less you present formally, the more and better comprehension you get.

This year, we started with energy bar charts in the simplest of situations - just with gravitational energy, kinetic energy, and work done by an external force.  Importantly, I didn't say what exactly work is.  We showed how work could be positive or negative, depending on what the bar chart requires - for example, if kinetic energy decreases with no change in gravitational energy, then negative work was done on the system in order to keep the right number of bars in the energy bar chart.  The students had access to a fact sheet which explained the direction of force and displacement for positive and negative work, but I didn't discuss or even mention this in class.

And so, every problem became an energy bar chart problem.  

Evidence, Greg?

Our trimester exam included several energy questions.  No one tried to use "W = Fd" inappropriately.

In particular, I assigned the classic problem to test this misconception.  Consider a baton: two massive objects connected by a very thin, light rod of length L.  The object of mass m is vertically above the object of mass 2m.  How much work is required to flip the baton 180 degrees so that the heavier object is on top?

Most years, the vast majority of the class uses W = Fd, getting all sorts of incorrect answers.  They make the d term equal to a part-circumference of a circle, they use all combinations of mg and 2mg and 3mg for the ill-defined "force"... ugh.

This year, no problems at all.  They made an energy bar chart.  They saw that gravitational energy went from mgL to 2mgL.  They saw that there must have been mgL of work in order to make the bar chart work.  QED.

I've never seen such success on this problem.  And all because I *didn't* teach something from the front of the room.


03 November 2019

Make appointments for students to attend extra help

I know it happened to me regularly in my first years of teaching... how many times has it happened to you?

"My daughter says you are mean and unapproachable."

And I would respond, with naivete but full intellectual honesty, "That's ridiculous - she's never once approached me outside of class.  How does she know?"

Winning an argument with a parent certainly isn't the point here... but nevertheless, I never won this argument.  Parents went away angry, complaining to my bosses.  The students who hid behind "he's mean and unapproachable" knew they had won a political victory, and became ever more hostile - even as I tried to encourage them to let me help them.

I only managed to turn the tide when I began making appointments with struggling students... and making those appointments the moment they turned in poor work.

Most of us have some time available during which we can help students outside of class.  In some schools that time is easily accessible.  For example, I'm spoiled - my school provides a 30 minute "consultation" time three days a week, time when no classes meet, but when teachers are required to be in their classrooms, available to students.  AND, my students have at least one "study hall" period, during which they are allowed and encouraged to meet with teachers.  Your school might not have such generously allotted downtime to work with students, but most teachers have some sort of time they can use - lunchtime, before or after school, etc.

I don't recommend that you wait passively for students to come to you during these extra-help times.  I also don't recommend that you make a general suggestion to a student like, "Johnny, you really should come see me during extra help time this week."  That sounds like nagging; chances are, if he shows up at all, he'll show up the last five minutes of the last extra help time this week just so he can tell his parents he listened to your suggestion.

I'd recommend you make specific appointments with students.  In the first few weeks of school, I spend way, way more time arranging these appointments than I do grading my students' work.

In large part, that's cause my "grading" of daily in- or out-of-class work is essentially a holistic slapping of a number on a page.  I only have two purposes in grading an assignment:
  1. Make sure students know I'm paying some attention to the quality of their work, and
  2. Find out who needs an appointment to come work with me. 
Appointments are not for people who make math errors, or who make a common error that I will address in class via a quiz or activity.  No, appointments are for those who don't follow proper methods,* or those who all made the same fundamental error because they followed a friend's advice blindly, or those who keep making the same fundamental error repeatedly on multiple assignments.

Proper methods early in any class include starting with a fact written directly off the fact sheet I handed out.  Proper methods early in AP Physics also include free body diagrams followed by N2L equations, or kinematics charts.  

I go to great lengths to ensure that I have common time to meet with the students who performed poorly on an assignment; and to ensure that I've communicated with these students, so that they know not only that I've asked them to come work with me, but exactly when they're supposed to show up.

What does it mean, "great lengths"? I email* students appointment times.  I write names and times on the board so students are continually reminded of their appointments.  I negotiate politely and enthusiastically to reschedule the student who has a conflict with my appointment, and I go out of my way to be understanding of and care for a student who is overwhelmed with concerns beyond physics class.  But if a student passive-aggressively tries to avoid an appointment, or fails to show up without discussing with me, I escalate to a discussion with the student's advisor or parents.

* You probably want to text, or use an app like groupme.  Apparently people under age 30 don't read email anymore.  Since I'm at an isolated boarding school with a central email system which is the primary source of community information, we manage to get students to read email.  At least the subject lines, anyway.

Now, if you're going to die on the hill of get your arse in for extra help, you've gotta make the extra help worth the student's time.  The extra help can't feel like punishment, it can't be the teacher re-teaching from the front of the room, it can't be the teacher basically doing the problems for the student.  

But that's a (very important!) topic for a future post.  For now, solve your political battle by getting the students in your room.  Just that personal contact builds relationships.  Just that effort preempts a whiny argument that you would otherwise have to deal with.  

This is a LOT of work, Greg.  I know.  It nearly kills me, every fall.  One important suggestion is to stop grading anything other than monthly major tests carefully to a rubric.  Just find out who needs appointments, and make them.  Replace grading time with making-appointment time.  It's not easy.

But see, very likely, the number of students whom you need to bring in will drop as a power-law over the first months of school.  It's November - I'm seeing just a few students each consultation period now, and only one student hasn't adapted to using the methods I require (and so only one student is truly performing badly).  In early September, I had a room full of nearly 20 students every consultation period.  In December, after our first exam cycle, I'll rarely have to make an appointment with a student at all - and no one will be complaining that physics is "just too hard," nor that the teacher is unapproachable.  Because I've done the approaching for them.

This happens every year.  The brobdignagian front-end effort to make appointments is so worth it.

31 October 2019

It's not about the answer!

I grade assignments regularly... but really, I just look and slap a number on.  What matters to students and me isn't the grade, but whether the student used the correct method.  And if they didn't use the correct method, they need to redo the problem the right way.

Last week I assigned the classic elevator problem: A 50 kg person stands on a scale in an elevator, moving up and slowing down with an acceleration of 2 m/s/s.  What's the reading in a scale?

How I ask students to solve: 
1. Draw the free body, which includes the force of the scale Fs up, the force of the earth mg down.
2. Acceleration is downward (slowing down, acceleration opposite of motion), so write mg - Fs = ma
3. Solve algebraically for Fs to get 400 N.

How a bunch of my students solved:
1. Draw the free body, which includes the force of the scale Fs up, the force of the earth mg down.
2. N2L says a = Fnet/m.  So (2) = Fnet / (50), making Fnet = 100 N.*
3. Now 500 N - 100 N = 400 N.

* Well, as you'd expect, half the class just said "Fnet = 100."  Sigh.

That's the right answer!  And the method couldn't have been much wronger.

No, Greg, it's totally correct to subtract the net force from the weight here to find the force of the scale!  And I got the right answer!  How dare you count that "wrong!"  Show me the mistake!  Don't take off points because I used an alternate approach!

Um, back off there, student who's been in physics class all of a month, or parent or colleague who is suddenly an expert in physics pedagogy.  We are NOT going to talk about points, we are going to be sure that each student has communicated an understanding of the problem.

Yes, you must use the methods taught in class.  In English class, if you're given instructions about how to write a new style of essay, and you decide you will write something completely different from the assignment... that's okay now?  So why is it okay here in physics class?  Physics is not about getting the answer, it's about communicating an understanding of how the natural world works. 

I brought in the students who had solved using the "wrong" method.  I made them do the problem again using the correct approach.

Think I'm being too harsh?  Here's what I discovered.  I mean, I already knew these things, but they were exposed to the students in the process of redoing this problem the right way:

* Most of the students thought they were solving for mg, not the force of the scale.  When they wrote "500 N - 100 N = 400 N," they meant that the scale reading minus the net force was equal to the "new weight".

* Most had no clue why they were subtracting 500 N - 100 N.  Once I made them redo this problem the right way, I had them do the next problem as well... where the elevator was moving downward and speeding up with 2 m/s/s of acceleration.  For this problem, these folks had added 500 N + 100 N!  Now they found out for themselves that their incorrect method had actually obtained an incorrect answer - the acceleration is still downward here, so the solution should be exactly the same as in the previous problem! 

* Turns out, as I suspected: One of the students who had taken physics at a different school, and sounds smart and assertive, had told the group how to solve.  Most of the class had blindly followed.  No worries, collaboration like this is an important part of physics learning.  And, learning that the smart kid isn't always right, that it's important to argue with the smart kid, is an even more important part of physics learning.*

* For the smart kid, the most important part is finding out that even they have to communicate carefully using the methods taught in class.

Today's moral: When you're "grading" assignments, don't just look for the answer - look for one component of the correct method.  In this case, I looked for a correct free body and "mg - Fs = ma".  I didn't write any comments one way or another, because no one would have read them.  I just made anyone who didn't write this statement redo the problem. 


27 October 2019

How do I "grade labs"? In class.

I had students write lab reports for the first six or so years that I taught.  I worked hard on getting students out of their write-as-much-random-bullcrap-as-they-can-shovel report voice, and into writing clear, concise, and precise prose.  But it took enormous amounts of time and political capital to turn students from writing procedures like this

We came into lab today in order to accomplish the goal of discovering the effects of a pendulum.  First we found our partners, mine was Willie.  He and I cut a sting precisely to multiple lengths, measured precisely.  We tied a lab mass which is called Bob to our precisely cut string and let the mass go from rest at a carefully and precisely measured angle that was not too big for Mr. Jacobs to holler at us.  We recorded all our data carefully in our lab notebook.  I forgot to say we measured the period of the pendulum, too.
into writing this
A pendulum of various lengths l, measured with a meterstick, was released from rest at a small angle from the vertical.  The period T was measured with a stopwatch by timing ten back-and-forth cycles and dividing by ten. 
I mean, it seems so simple... but it's not.  Convincing just one student to adopt the simple but appropriate style in the latter paragraph took multiple re-writes, several writing conferences, and too often several arguments with students, advisors, and parents.  ("What do you mean, I failed, I wrote lots of words about a pendulum, didn't I?  That's not worth even a C?  My English teacher gives me a C for that!  This is entirely unfair.")

Multiply the time and mental effort investment by the 50 students in my classes, and, well... it just wasn't worth it.

So what do I do if not lab reports?

Nowadays, we do most lab analysis in class. The students collect data collectively, but they graph or re-graph that data individually - especially if they are linearizing a graph.  Next, they draw best-fit lines and take slopes using far-separated points on the best-fit lines that aren't data points.  This is all on a worksheet that looks like an AP Physics 1 free response problem - a grid for graphing is provided, and several questions are asked with space included for responses.

Students are asked to describe their procedure in "no more than three sentences", including what they measured and how they measured it.  They're asked to explain the physical meaning of the slope of the best-fit using direct reference to the y = mx + b equation of a line.  And then they are asked to determine that physical meaning, with an uncertainty.

Because we're doing this in class, students come to my desk after each part for me to check.  If it's right, they get a stamp and move on.  If it's wrong, they get immediate feedback and do it again right there - with 15 peers working on the same thing, so that they can ask questions and get help without trouble.

This is so, so much better than having students write lab reports or even answer lab questions at home.  See, they tend to do the work at home for the sake of getting done, right or wrong be danged.  (If you think the grade is what motivates the student, you're sorta wrong.  B or C students do the work as quickly as possible, right or wrong.  A students spend way too much time stressing about perfection, still getting the answers generally wrong, they just get angry and uptight about it.  And D or F students don't do the work at all.)

By working in class, everyone focuses not just on finishing, but on doing it right - in fact, they can't finish unless it's right.  And then if someone is slow, they can finish at home... but they've listened to me give feedback to all of their classmates, and they've had feedback themselves on the first part of the lab sheet, so they're more likely to get it right than if I had just sent everyone home to write a lab report.

30 September 2019

Right before the first test...

We are a month into my senior AP Physics 1 class.  Therefore, our first test is coming up.  It involves everything we've discussed so far - equilibrium, kinematics (including projectiles), and Newton's second law in one dimension.

Students have been solving AP level problems this whole time, both in class and on homework.  They've been taking (timed) daily quizzes, involving both basic fundamentals questions and more involved problem solving.  They've done lab activities, including data collection and analysis.  

But with the test coming up, &#*@ just got real.  I need simultaneously to build confidence, but also to create realistic expectations.  These folks will be working under some time pressure, and without a safety net - no collaboration, no questions, no notes, no coming back later to finish a tough problem.

So I gave the quiz below in the first five minutes of class today, the class before the test.  I had students trade and grade it (though I didn't collect it).  

My top students got 7 out of 11 on this quiz.  My not-top students, um, didn't get 7 out of 11.  Everyone had deer-in-headlights faces.  The subsequent discussion was about...

Building realistic expectations:  "Folks, these aren't just memorize-and-spit back questions, eh?  You've got to know your facts, but also how to apply them to completely new situations.  This is what an AP exam is like!  Better get used to it... the level of the exam comes from the College Board and their development committee, not from me.  It is what it is, and is not changing.  No whining.  Deal."

...but also building confidence: "Once I explained each answer, it made perfect sense, right?  I saw you nodding your heads, or smacking yourselves on the forehead 'cause you understood just fine in retrospect.  You get this stuff.  And, remember the grading scale: 65-70 percent is a 5; 50% or so is a 4.  Most of you got the equivalent of 3s and 4s.  You're expected to be brave, not perfect.  Relax, show me what you know, and expect to figure the rest out when we do test corrections."




24 September 2019

The most profound math lesson

Mrs. Barson (my kidnergarten teacher at Lotspeich School, Cincinnati) still holds my standard for the most profound moment in math teaching.

It's 1978.  We’re in a circle during math time. Each person in turn says a number.  After which, the whole circle is supposed to say the next two numbers in sequence.  Like, Amanda said “156”, and we all counted together, “157, 158.”  

After a bit of this, my girlfriend Rebecca* looks mischievous.  Something fun is about to happen.

* Our favorite activity as a couple was to pick *four* digit numbers and harass Mrs. Barson by telling her what the number was called.  The class had been told not to pick more than three digits. Rebecca and I were offended by that rule - we knew about numbers in the thousands! Don’t doubt our intellect!  I suspect, with 40 years of perspective, that the rule was less about our intelligence and more about the limits of Mrs. Barson’s patience for showing her excitement at 5 year olds spitting out super-long words.

Our class has been proudly spreading the secret that “infinity” is the biggest possible number.  We are collectively smug in the knowledge that we have somehow thereby conquered mathematics.

"Infinity," says Rebecca.  She smiles, thinking she’s somehow “won” the game.

Mrs. Barson doesn’t miss a beat.  She leads the chant:  “infinity plus one, infinity plus two...”

[Five year old mind explodes.]


05 September 2019

What do I do if I am teaching AP Physics but I don't know physics?

A teacher got switched from teaching chemistry, in which she is a subject matter expert, to teaching AP Physics 1, in which she is emphatically NOT expert.  She is well aware that students in high-level courses like this tend to be "students who care," and she fears also that such students "can tell when a teacher has no idea what they are doing."  This teacher is quite worried about the high-stakes of the AP Physics 1 exam; she feels behind already, like she can't give her students the education they deserve.  

On one hand, it is entirely unfair - to this teacher AND to her students - for the district to put them in this situation.  "Here, Greg, teach AP art and design!"  Yeah, right.  Not gonna go well.  

However, for all kinds of systemic reasons, an enormous number of science teachers are forced into this same situation every year.  I meet them in my summer institutes.  What advice can I give?  

Look... you can't fake physics.  Students do and will know that you're not an expert.  But, and this is important... THAT'S OKAY.  I've had plenty of teachers just like you in the APSIs that I run, and they do very well - as measured over a three year period.  

The suggestion is, be open and honest with your students that you are learning AP physics alongside them.  Do every assignment with them.  Put yourself in lab groups with them.  You can use my tests - and take them yourself, with the students.  Use the AP Classroom personal progress checks, just like the students do.  Don't be the authority figure, because students will rebel.  Instead, be the captain of their team.

Your goal this year should not be to know anything about physics now, or next week; but instead, to get a 5 on the AP Physics 1 exam in May, if you were allowed to take it.  :-)

Then, have a three year outlook.  That's how long it takes to become comfortable teaching AP Physics.  You are not doing your students a disservice - you're giving them the education they deserve, because they deserve an ally who will do whatever it takes to learn physics alongside them.  You have to learn sometime.  And if this year's class gets the less-than-perfect you, so what, because you have a long career ahead of you; if you have a couple of rough years followed by decades of hard-earned expertise, well, you're serving the next generation more than well.  

The students will respond to your humility, earnestness, and hard work.  Okay, well, MOST of them will.  That's okay, 'cause after 24 years I don't always get every student to respond to me.  I have to be like a football cornerback, who usually prevents touchdowns, who cares deeply about preventing touchdowns... but who has to be able to recover instantly when he gives one up.

Oh, and do make extensive use of the AP Physics 1 workbook, available through your course audit.  It's designed explicitly for people in your situation.  You have students (and yourself) working through that, you'll be pointed in the right direction.  I'd also say get the 5 Steps to a 5: AP Physics 1 book, but that'd be self-promotion and I don't do that, at least not very often.  :-)

Good luck... 

27 August 2019

Embracing chaos in the physics lab

I run week-long AP physics summer institutes, which are essentially classes on how to teach AP Physics 1.  In terms of expectations and attitudes, these institutes turn into a microcosm of my full-year classes for high school students.

My students - and the APSI participants - have been conditioned to believe that the spectrum of good and evil is contiguous with the spectrum of lawful to chaotic.  Problem is, learning is not linear; learning does not obey neat rules.  Many of my best students would not be labeled “lawful” in a role-playing game - they’d be neutral, or very often chaotic.

I totally understand that, in an elementary classroom, chaos simply must be tamed into order so as to avoid the Hobbesian State of Nature that would otherwise be, well, natural.  If it's done right, elementary education should be far more about establishing how to relate to one another in civil society as about serious academic content.  Just as with the rules of writing or musical composition, rules of school must be learned and internalized before they can be professionally broken.

But physics students are emphatically not in elementary school any more.  They know well the rules of appropriate class behaviour and relationships.  While it is certainly important for teachers to intentionally build a positive class culture, we absolutely do not need to use elementary school style rules.  

Nor do we need any "rules" at all.  

When an authority figure dictates to a teenager an externally-imposed rule, the teenager rebels.  Sometimes that rebellion is external, with derisive body language, passive-aggressive or even actually-aggressive speaking out.  Probably more often the rebellion is internal.  A teenager may have learned to present submissive body language and to control their tongue.  Yet, teenagers sneer in their heads, they make plans to break or test each rule, they convince themselves the rule doesn't apply to them, they know from experience that they won't actually be held accountable to the rule.*

*Just as often the teenagers simply didn't register the rule at all because they were thinking about sex when the rule was presented.


***



At my summer institutes, I begin by talking to the group from the front of the room using powerpoint slides.  Why?  Because that's what participants expect.  They'd be confused, uncertain, and in most cases angry if I began the week by saying "pick your favorite AP problem and set it up experimentally right here with no guidance or instruction from me, the guy you're paying to give guidance and instruction."


By the middle of the first day of an institute, I've moved on to quantitative demonstrations - still me talking from the front of the room, but using physical equipment to verify the predictions I make on the white board.

Then by day's end, I've stopped talking at the board altogether.  Everyone does a motion graph activity, in which they individually communicate their predictions about the motion represented by a graph.  They bring their predictions and justifications to the front of the room, where I either help them communicate their prediction better... or I check off their prediction, at which point they go to the back of the room to use a motion detector and cart to reproduce their assigned graph.

During this last activity, I don't move - I sit at a desk, talking to each participant in turn as they come to me in a line.  In front of me unfurls a scene that would make my second-grade teacher's head explode.  Participants talk to each other, they physically walk from one classmate to the next seeking suggestions, they drop equipment, they set up equipment in both right and wrong ways... and all the time, I sit there, making not even an attempt to control the chaos.

It's not about control.  It's about lawful chaos.

See, I don't believe in Hobbes*.  Left to their natural state, students certainly are chaotic, but they are not usually selfish.

* Using synecdoche here about Leviathan - not referencing Hobbes the Comic Tiger, whose existence and philosophy I wholeheartedly support.

I don't give the institute participants - nor my students - a list of rules, guidelines, or instructions for this activity*.  Nevertheless, goodness rules.  People help each other, both with the predictions and the experiments.  They discover naturally who has the same graphs to work on, and so "lab groups" form organically.

* The one "rule" that applies here and throughout everything my classes do is the "Five Foot Rule" - students may collaborate freely, but they must separate themselves by five feet before writing anything to be turned in.

In my classes that run in this manner, it's quite rare that I have to call out a student for being "off task."  My tolerance for chaos must be high, of course - I can't be a control freak.  Yes, it often happens that I hear students talking about the upcoming football game; yes, I can occasionally see a student check a text message.  I've got to hold my tongue.  I only say something when the conversation becomes more than a short break - and then I am extraordinarily careful to be polite and respectful.  "Hey, Mr. Jones, I'm coming to your game today, let's talk about it there, okay?"  I don't take a phone away unless students truly can't control themselves - and then I'm still as respectful as I can be.  (The one time years back when I got outwardly frustrated with a student on a cell phone, I severely damaged the relationship with him and at least one of his friends.  My frustration was justified - yet my reaction hurt the situation, it didn't help.)


How do students know what is appropriate or inappropriate if I don't go over rules and guidelines?  They know because they are human beings with 14-19 years of experience interacting with other human beings.


Look, I recognize that's a flippant answer.  If you're asking this question - which I know many readers are - it's not because you're incompetent or stupid.  It's because you're legitimately worried.  Probably you're worried in particular about that one student who thrives on negative attention from their peers and teachers.  What if they don't even pretend to do physics, but instead go from classmate to classmate causing distractions, deliberately sowing the seeds of churlish negativity?  And then, how do you defend yourself to an administrator when you ask the student to leave, but (s)he says with false sincerity, "I didn't know what to do! I didn't know it wasn't okay to talk about non-physics things, and teacher didn't give us any rules or guidelines!"?

That's a battle that many of us, unfortunately, will have to fight.  But rules won't help.

If your administrator is giving any credence whatsoever to such a disingenuous complaint, then this administrator isn't going to suddenly come down on your side if you can show them how the student violated subsection (b) of class rule 3.2i.

Find a way to deal with the one underminer.  Don't seek justice, seek peace - that is, you don't need disciplinary consequences for a pain-in-the-butt student, you just need to be able to separate them from the class when they're not engaging.

This way, the rest of the class won't be afraid to relax and have fun.  Fun is chaotic... and that's okay.

21 August 2019

I'm teaching a fall 2019 online course in physics/physics pedagogy

Hey, all... this is an ad, but an ad for something you or someone you know may be interested in.

I'll be teaching an online physics course on circuits through the Putnam-Westchester Industry & Science Teacher Alliance (PWISTA).  Check out the Science Teacher Mastery Program.  Each class in the program is equivalent to what would be a two-to-three week content unit in a first year college physics course, but aimed at students who are * physics teachers.

* or intend to become

Do you know someone who is familiar with physics, but needs guidance in physics pedagogy, needs to know how to help her or his students understand physics?  Or, do you know someone who is being asked to teach physics, but is primarily a biologist or chemist and thus needs some content support?  Either way, this course will be of use.

I'm offering just one class this fall: Circuits.

For each, you will get access to all of my topical course material, both when I teach at the high-school (Conceptual or Regents) level, and when I teach at the college (AP) level.  This includes the labs, problem sets, and quizzes that I assign.  I'll give you written guidance about how to use this material in your teaching, and for your own study.

Then, I will host five one-hour online sessions on Thursday nights this fall (see schedule below).  In each session, I'll spend the first half discussing practical pedagogy, just as I do in my workshops and on this blog.  In the second half, I'll discuss specific content, problem solving, and test preparation issues as requested - or, I'll improvise where the participants take me.

See, I'm more than happy to address individual needs.  For each class, I will be videoconferencing via google hangouts from my labThis means I can show live experiments.  And, as people have questions that stray beyond the circuits demos I had set up, we can improvise to talk about anything of interest to the folks who sign up.  Yes, we're going to learn about circuits... but I'm happy to discuss whatever is on your mind with regard to your physics classes.

Participants can get 15-hour CTLE certificates and/or university credit hours through Purchase College.  They can also get three graduate credits in science education through Manhattanville College - see the site for details about credits, certificates, and pricing.

You can see the full course description via this link.

If you have further questions, please contact me via email or twitter; or, contact Mark Langella, head of PWISTA, through their site.  Mark teaches the chemistry courses, and has been a College Board consultant for many years - he's the varsity, in case you know anyone who wants a similar program in chemistry.

Schedule for PWISTA Physics fall 2019:

The following are Thursday night classes.  I'll meet each night from 8:00-9:00.

Sep. 26
Oct. 10
Oct. 24
Nov. 7
Dec. 5
(Dec. 12 available as an alternative.)