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13 February 2019

First year physics teachers - please don't despair. Plan for next year.

I have horrible memories of February 1997 - or rather, I have suppressed most of this era to the deep recesses of my inaccessible long-term memory, right alongside the times Chris Jobert secretly stole my math homework in third grade.*

* I got a C- in math that year, and was shamed for irresponsibility.  One day I even discovered the homework ripped up in the bottom of the garbage can by Jobert's desk - and I remember thinking, "When did I rip up my homework?  Why did I do that?  I'm in so much trouble..."  Things turned out okay: I ended up with a degree in physics, and Chris ended up with an arrest record.  Suppression time again.  Toot toot, here comes the happy train!

What was so awful about February 1997?  It was the depths of winter in Chicago during my first year teaching.  I had been (figuratively) beaten down for six months, with end of the school year not yet close enough to fathom, and in an inextricable downward spiral in relationships with my students and my colleagues.  Parents had complained about me so much that the school brought in a special mentor just for me - never mind that my middle-aged, "experienced" co-teacher needed mentoring or a good kick out the door far more than I did.  Students had been as successful in their smear campaign against me as Russian trolls were with Hillary Clinton - colleagues and administrators believed whatever negative things students said about me, no matter how outrageous, no matter how untrue.  My principal (who somehow, unfathomably, still has a job) once even sat by silently and allowed a parent to berate me for 45 minutes about claims that were exaggerated, spun negatively, or simply false.

I've said before - I really don't know why I stayed in this profession.  

I'll bet this sounds familiar to you.  Everyone was a first year teacher; some of you are right now.  I hear versions of this story so, so often in my workshops, in conversations in the physics lounge.  You feel like you stink at this.  Teachers and administrators offer condescending, unsolicited, and out-of-touch advice; the colleagues you observe seem to be holding classes and lab exercises every day that you might be capable of running once a month if you prep for hours.  You wonder why you're wasting your time and your life in a Sisyphean job in a hostile work environment where you're not appreciated.

Take a long-term view.   It is a sad, systemic indictment of our schools that we allow and almost expect first year teachers to be beaten down.  Yet things do get better. 

It's practically impossible to change a classroom culture in February.* That's as true in your 24th year as in your first year.  So don't try to work miracles!  If your students seem hostile in class at this point of the school year, all you can do right this instant is keep calm and carry on.  

*Impossible to recover from a negative culture, yes, but the good news is it's also impossible to bring down a positive culture once it's well established.

Build what relationships you can.  Aim your teaching at the subset of students who are NOT hostile, who wish the loudmouth haughty disrespectful arses would shut up.  Consider that these students feel as helpless as you - and they've likely had to deal with the arses for many years, in many classes.  Develop your relationships with them.  Hold your head high for them.  Keep on working hard for them.  Think about them when you arrive home each day.  They do and will appreciate your efforts and attention.

Make plans for next year.  Though it's tough to change a classroom culture right now, you can consider how to pre-empt negativity from the beginning next year.  Some of that advice that seemed so disconnected from your current reality might work well if implemented next August.  Your initial idealism about this job has been blunted by hard-edged practical reality.  The positive spin on this is that you know what you need to do for next year.  Make plans.  Write plans.  Edit the activities that didn't work, and do so right now before you forget.  Keep everything you've done in soft copy; plan some time this summer to organize those computer files so that you have something to fall back on when you need a last-minute class idea.  Make notes about things you wish you had done or said that might have established a better tone.  Consider how you could have dealt better with the first kid's complaint, such that the second complaint was less likely to happen at all.

Epilogue.  I wasn't hired back at that first school.  

The students found this out right after spring break.  And a couple of days later, the headmaster found a petition on his desk signed by the vast majority of my 60 students requesting that he reconsider his decision.  The headmaster never said anything to me about this - the bastard - but the students did.  Many students.  Some students who I thought hated me.  Some who had been angrily silent at the stupidity of their peers.  Some who had been friends to me from the beginning, though I had been so depressed I almost had forgotten.  Some who suddenly became vocally upset that there wasn't a place at their school for a teacher like me.  

Point is, even in what were my darkest professional times, the students whom I had tried to care for cared back.  They noticed.  

Their petition was hopeless - since when can students get an administrative decision overturned, plus I had to politely explain that even if the headmaster changed his mind, my relationship with him and the school was irrevocably damaged.  Yet those students gave me strength and hope that perhaps I could succeed in this business.  Sure enough, I went on five interviews and had my pick of two good teaching jobs.  The next year, even at a new school, was far smoother because I didn't make the same mistakes twice.  (I made new mistakes, but I learned from those, too, in the long term.)

I still have occasional sleepless nights in which I seethe in anger at something school related.  That never totally goes away, unfortunately.  I wish that I weren't a permanent outsider to not just my current school's culture, but to that of every school in America; I wish bullies - both adult and teenaged, both deliberate and accidental - didn't exist; I wish that successful teachers garnered the same public respect as successful football coaches or singers.  I wish frogs had wings so they didn't bump their arses on the ground when they hop.

If you still believe you can help your students learn physics, I hope you'll stay the course.  Teaching can be overwhelmingly rewarding.


12 February 2019

What do my students have to do to get credit on the AP exam? (They have to *communicate*.)

We're in the time of year in which AP classes have discussed enough material that they're trying out more and more authentic AP questions.  And teachers are grading to authentic rubrics, trying to give students advice about earning credit.  

There is only one piece of advice your students need:  communicate clearly.

Should I teach my students to box their answers?  If you insist... but who cares?  If your student clearly communicates the steps toward the answer, the reader will follow.  

But if they don't communicate clearly, won't the boxed answer help the reader find the answer?  Maybe, but credit isn't always awarded for just the correct answer.  (In AP Physics 1, there's hardly ever a numerical answer, anyway.)  I strongly encourage teachers not to teach games or tricks.  Rather, insist on clear communication from the get-go, such that "always box your answer" becomes as redundant as reminding an opera star to project her voice.

What if a student uses notation different than our textbook?  Is the student clear about what they mean?  Then it's okay.  For example, some texts teach to call rightward forces "positive" and leftward forces "negative", then add the forces using signs.  Others suggest subtracting the right forces from the left forces.  Who cares?  If the student clearly articulates their approach, if the student is consistent and correct in applying Newton's Laws, that's all good.  The exam is graded by physicists, not lawyers - readers rarely stand on ceremony about a notational issue unless it makes the physics wrong.

But what if they lose a point because...

Relax!  All these sorts of hyper-specific questions from teachers usually boil down to a student complaining about losing points on an assignment.  We have to elevate the conversation so that we're not arguing about points, we're teaching how to communicate physics principles.

When your student has an authentic question about how you applied the rubric, or about the physics concepts underlying the rubric, certainly answer as best you can.  But read your student's body language.  When they roll their eyes and throw up their hands, showing everyone that teacher is pond scum who obviously is too stupid to hold a job; or when they use the wheedling tone of a car salesman suggesting they might throw in free floor mats if you'll award the point; stop.  Don't engage.  You're not going to win the argument.

Winning the argument isn't the purpose of the exercise.

I understand the difficulty of a teacher's position here... if you're not an AP reader, you are trying your dangdest to interpret official rubrics, and to apply them to responses that you're not sure about.  Where can you go for guidance?  You're looking for hard and fast rules, clear boundaries between right and wrong.  You must recognize that such boundaries simply don't exist.  Even at the reading we see edge cases, responses that are quantum superposition states of earning a point and not earning the point.  

The best advice I can give is to ask, "did this student clearly communicate a physically sound approach to the problem?"  If not, don't award points.  The burden of proof is on the student.  When in doubt, it's wrong.  

Now, don't be nit-picky... consider that the audience for the clear communication is an intelligent person with the same level of physics knowledge as the student.  

But at the same time, don't read in to what the student has written; don't let the student argue about what they meant to say.  It doesn't matter what they meant to say; we grade what they did say.  I've never yet, in 20 years of reading AP exams, had a student follow their exam around the reading rooms lobbying for points, telling the readers what they meant.  And so I don't allow such a thing in my classroom.

In the end, grading AP problems is like calling balls and strikes.  Do your best to establish a zone.  When it's close, call a strike without hesitation or second thought.  When someone looks at you funny, smile and move the game along.  As long as your zone isn't ridiculous, as long as you seem kind but firm, everyone will just shut up and play.  And that's what we came to the field to do, after all.







02 February 2019

US Invitational Young Physicists Tournament - results 2019

Last weekend (January 26-27, 2019) Rye Country Day School hosted the 12th annual USIYPT.  There, teams compete in "physics fights" over four problems, this year involving:  

     * Faraday's homopolar generator
     * Rainbow formation on this and other planets
     * Pneumatic tubes, and scaling them up for transportation
     * How a hammer twists in the air when tossed

This is not a science fair!  Teams report unique solutions, yes... but before the jurors say anything, the other team engages the reporter in conversation and questioning.  The jurors' job is to evaluate the strength of the physics in each team's discussion.  The USIYPT is more similar to a scientific conference than to a typical high school contest.

This year's winners, for the second year in a row: Phillips Exeter Academy of New Hampshire, led by physics teacher Scott Saltman.

In second place was Phillips Andover Academy of Massachusetts, led by Mika Latva-Kokko.

The winner of the Swartz Poster Session was the Pioneer School of Ariana, Tunisia, led by Safouen Rezgui.  

The overall order of finish is below.  Our rules state that a number of places are shared by similar teams - this is to emphasize that just participating, merely being able to engage in high level physics fights, marks a team as among the best high school physicists in the world.  

The ** means that this team won the prestigious Bibilashvili Award for Excellence in Physics.  It is awarded to teams with superior physics understanding, irrespective of their placement, at the tournament director's discretion.

Champion:
     Phillips Exeter Academy, NH**

Second place:
     Phillips Andover Academy, MA**

Third place:
     Woodberry Forest School, VA**
     Shenzhen Middle School, China**
     The Nueva School, CA**

Fourth Place:
     Cary Academy, NC**

Fifth Place:
     The Harker School, CA**
     Pioneer School of Ariana, Tunisia**

Sixth Place with Bibilashvili Medal:
     Rye Country Day School**
     
Sixth Place, in alphabetical order:
     Pioneer School of Menzah VIII, Tunisia
     Qingdao No. 2 High School, China
     Spartanburg Day School, SC
     Vanke Meisha Academy, China


How do you participate in the USIYPT experience?  

Our 2020 tournament will be hosted at Phillips Exeter Academy in New Hampshire, on Feb. 8-9.  I'd suggest starting out by serving as a juror.  We try to get jurors from all sorts of backgrounds... retired folks, industry professionals, university professors of all sorts, high school teachers, graduate students, undergraduates, etc.  Juries develop a deep and special camaraderie after a day or two discussing physics with each other and with students.  If you have a background in the physical sciences, we'd love to get you involved.  The sponsoring organization (USAYPT) can put you up in a hotel for the weekend, and we'll invite you to the much-anticipated annual Juror Dinner.

To bring a team, start by taking a look at the problems for 2020.  Your team must have a ten minute report prepared on three of these problems.  Then the physics teacher at the prospective school should email me to request an invitation.  Later in the summer, we will post information about fees; we'll issue invitations in September or so.

I'm always happy to discuss the USIYPT experience.  The tournament is, every year, the highlight of my professional life.  Those who participate contribute to a special, unique culture in which the "Search for the Truth" of physics leads to discussions, debates... and long-lasting friendships.

Greg Jacobs
President, US Association for Young Physicists Tournaments

14 January 2019

They did it - 2015 P1 #3 with PASCO smartcarts by Nadia Lara and Joey Konieczny

Last month I showed how I had set up an AP physics problem in lab using a motion detector.  I suggested that a PASCO smartcart would allow for a higher data collection rate in order to better define the energy vs. position graph.

Well!  Two physics teachers wrote in with their results!  I post both below, with their own words.  Take a look at Nadia's to see how to use the Sparkvue app to get the kinetic energy data to display.  See Joey's for a picture of his setup and how to adjust the = 0 position.

First is Nadia Lara of St. Agnes Academy in Houston.  Her writing is available at her blog, Need to Know ScienceShe says:

I set up the problem you wrote about last month and got the following graph with a 100 Hz sampling rate:

I used the spring attached to the smart car on the second setting. It’s pretty stiff, so the curve is steep and it’s harder to see the quadratic vs. linear relationships, but you can get plenty of data points. Higher sampling rates didn’t work well. A weaker spring would work better. I ended up taping a piece of a balloon on the bottom of the car to get enough friction to slow the car down quickly. 

To get the calculated values, click on Experiment Tools on the bottom right, then choose “Calculated Data” -->

Type in your formulas. Use the orange “Measurements” button to select the measured quantities you want to insert into the equation.

To edit the units associated with a calculated value, place the cursor on the line of the quantity you want to update and click the Properties button. Click the keyboard button next to the units and type in the units you want.

Voila! 


Thanks, Nadia! 

Now Joey Konieczny of Atlanta's Drew Charter School:

I was [bored in a place where it's politically incorrect to admit to boredom], so I pulled up your blog and accepted your challenge.  It took me a few trials to get it right, but below is my setup using the Smart Cart and two snapshots [overlaid on the same graph] from SparkVue showing Kinetic Energy vs. position.  In Trial 5 I pressed record (this sets the zero position for the wheels) and pulled the Smart Cart back only the length of the piston.  You can see from the graph that the Smart Cart thinks that zero position is actually about 15 cm ahead of where I told it zero was.  Trial 7 I "cheated" and moved the cart forward 15 cm (pulling it back a total of 20 cm) and voila!  The Kinetic Energy calculation (y-axis) was pretty easy, and Pasco has a ton of online resources to help figure it out.  

I'm a huge fan of the Smart Carts.  The data they spit out is awesome!



Thank you, Joey! 

13 January 2019

So why isn't the projectile changing speed at its peak?

A previous post posits a question, and a student's response.  The response seems okay, because every sentence is in fact correct.  But a logical connection isn't there.  Today I'll explain the error in reasoning, and give the better answer.

See the previous post here.  It discusses how to handle the conversation with the student who knows that they're right, even though they're wrong and you can't quite articulate the error on the spot.  That was my purpose in posting this question, as I had heard quite a bit of debate in the physics teaching zeitgeist about this problem.  I'm only posting the solution separately so as not to distract from the pedagogical message of the first post.

Here's the question:

A projectile is thrown upward at an angle.  At the instant the projectile is at the peak of its flight, is the projectile gaining speed, losing speed, or neither?  Justify your answer.

A student responds, "The path followed by a projectile is a parabola.  At the peak of motion, the slope of that parabola is flat, or zero -  the change in speed is zero.  The projectile neither gains or loses speed."

What's wrong?


The student connects the slope of the projectile's path to its speed.  That's not right.  The slope of a trajectory - the path that an object takes - says nothing about speed, just about the direction of motion at that instant.  [The student may well be confusing the slope of the projectile's path with the slope of a position-time graph, which does indicate velocity.]


What's the better answer?


At that instant, the acceleration is downward, and the velocity is horizontal - thus there's no component of acceleration in or opposite the direction of velocity, so the object cannot speed up or slow down.


Or:

At that instant, the net force on the object is downward, and the instantaneous velocity is horizontal - thus there is no work done by the net force, and so the object's kinetic energy cannot change.

12 January 2019

How to address students with incorrect reasoning when you can't identify their exact mistake?

A projectile is thrown upward at an angle.  At the instant the projectile is at the peak of its flight, is the projectile gaining speed, losing speed, or neither?  Justify your answer.

A student responds, "The path followed by a projectile is a parabola.  At the peak of motion, the slope of that parabola is flat, or zero -  the change in speed is zero.  The projectile neither gains or loses speed."

Right or wrong?

Wrong.

"Wait, what?" says the student.  "Everything I said is true.  Where's my mistake?"

Deconstruct the student's response sentence by sentence, and you'll find that yes, everything they said is in fact true:

The path followed by a projectile is a parabola.  Essentially a fact.  
* At the peak of motion, the slope is zero.  Yes.  Draw a tangent to the trajectory at the top - horizontal line.
* The change in speed is zero.  That is the correct answer, as indicated in the key the teacher read online.
* The projectile neither gains or loses speed.  That's what "change in speed is zero" means.

"So if you can't find my mistake, you can't count it wrong."  [Cue body language of rolled eyes, upraised palms, indicating that the student is dealing with a lesser being, someone on a lower social and intellectual plane.  Their body says, "I can't wait until I have the money and the power to properly avenge myself upon this plebe."]

It's tough not to cave in to a smart student making this kind of complaint... when you know in your experience that the student is wrong, but you can't explain the error clearly, and the student is starting to get frustrated at what they perceive as your intransigence.  It's tempting to say, "Okay, you must be right, the key is wrong."  Or, "Well, I see your point.  Since we are both so confused, this must be a bad question.  I'll throw it out."

Don't do that.

But also don't do the "Shut up, I'm the teacher, I'm always right, sit down" routine.  No matter how polite you are, just pursing your lips and firmly ending the argument will be perceived as an over-the-top exercise of authoritay.

What do you say?

"Look, I can't pinpoint the error in your answer right now, but I'm pretty sure it's there.  I need to look carefully not just at each statement, but at the logical connections between each statement.  I'll look at this tonight, and I'll see if I can give you a better explanation tomorrow."

Then if you're still struggling, email a colleague, a mentor, or me.  You'll figure it out.

A couple of teaching points: 

* This kind of argument over physics is healthy and important.  That's how scientists operate - they argue through difficult problems.  However, be sure that the argument stays respectful at all times.  The teacher shouldn't pull out the authority card; but at the same time, the student can't be displaying disrespectful body language.  The argument is not about points or grades.  The argument is about physics.  

* This sort of conversation is exactly why I recommend starting out your AP Physics 1 class with AP Physics B-style calculational questions.  A student generally doesn't argue if the answer key says "20 m/s" but their answer says "12 m/s".  To them, numbers have an authority that mere words do not.  The best way to avoid fights with students about subtle issues with explanations is to first build trust in your competence and fairness using problems with unambiguous numerical answers.  As you build in verbal response questions gradually over the year, the students will get used to discussing physics not points.  They will get used to the idea that they are supposed to answer in writing the first time, not come to you later trying to explain what they really meant.

* The beauty of teaching a full-year class is that there's always time to think overnight.  Nothing is so urgent that it needs an answer right now.  (Contrast that with baseball umpiring, where "let me think for a while about whether you're out or safe" doesn't win friends.)  Take the time.  Very often, you'll discover that the student who was so upset today doesn't really care any more tomorrow - teenagers live in the moment.

* Oh, what exactly is the error in this student's logical connections?  I'll save that for this later post here.

06 January 2019

Collect assignments seat-to-seat rather than having students stack them up.

The typical way to collect assignments is to have students pile them in the front of the room.  This takes a frustratingly long time.

Especially if there's stapling to do.  Each student in turn, with a huge line behind them, painstakingly aligns papers just so before gently, gently, gently! applying the staple to just the right spot.  Then they check the staple the same way a six-year-old might self-satisfyingly inspect a booger, before reluctantly ceding the stapler to the next person in line.  And the process repeats.

You don't have the opportunity to shepherd the line or encourage haste, because four students, mouths flapping like baby birds begging for regurgitated fish, compete for your attention.  Three are offering excuses or asking for extensions; one merely has a question requiring an answer - right now! - about whether quantum wave functions influence Confucian philosophy.

At least three in a class of twenty will fail to turn in their assignment without calling for your attention.  Usually this is because they didn't do the assignment; but plenty of times it's because they simply spaced out during collection time.

"Do I have everyone's paper?" you ask.  The three students with delinquent assignments don't answer.  Yes, one is deliberately and passive-aggressively ignoring you, hoping you won't notice.  But one is honestly thinking you're asking about a different paper entirely.  The other one is thinking about sex and so didn't process what you said.

When you finally get around to going through the stack, you see that one person (most likely knowingly) left the second half of the assignment blank; this student and three others failed to put names on their work.

AARRGH!  What can you do?!?

You can't complain about slow stapling, or holler at folks to hurry the process up - you'll sound like an officious, nagging arse.  You can tell the hungry birdies to talk to you later, but they will still try to talk to you now.  You can call out individuals, asking whether they turned in their assignment; but you're using even more time, you might call out the wrong people, and you sound like an officious, nagging arse.  

And you can't wait until later to check who's turned in the work, because as soon as the students leave the room, they've forgotten about whatever they were supposed to turn in.  The assignment doesn't serve its purpose - getting students feedback on their understanding - if the students avoid showing you their understanding in the first place.

When I finally snapped, I decided to collect papers from each student's desk individually... and I've never gone back.

I bring the stapler with me so that *I* do all necessary stapling.  If someone doesn't have the work, I can charge an extension or make immediate arrangements for the student to get the work done at an alternate time.  I can glance at everyone's work as I pick it up, so that a substantially incomplete assignment gets the same treatment as a missing assignment.  

Most importantly, the collection process usually occurs while students are working on a quiz or on some sort of timed, quiet, individual work.  No one wants to tell a long story that invariably ends with "and therefore I don't have the assignment" - no, they want to get back to the quiz, so I just hear "extension, please."  If they forget to put their papers on their desk, they grab from their bookbag quickly and quietly when I come to their desk.  With an established routine and practice I can get a 15-20 person class collected in about two to three minutes.  

Note that this collection method isn't only for homework!  Any written assignment, any at all, can be checked this way.  I once saw master physics teacher Peggy Bertrand walk through the class putting her custom stamp on each student's problem log to mark their progress.  I've collected index cards with "check your neighbor" answers on them, shuffled, and picked one person to explain to the class; by collecting from each student's desk, I can be sure every card has a name and some sort of answer on it.

As always, I don't claim to have The One Right Way to collect assignments.  I'm merely sharing something that's worked for me...


26 December 2018

Setting up authentic AP problems in lab - 2015 P1 #3

One of the all-time best sources for college-level, open-ended laboratory ideas is the AP exam itself.  While some AP problems are explicitly posed in an experimental setting, the large majority of the released problems - free response and multiple choice - can lead to an interesting laboratory investigation for students in the latter half of the school year.  See this post, this post, this post... you get the idea.

It took me several attempts over the years to get decent data for 2015 AP Physics 1 problem 3.  (Here's the link to the 2015 free response questions.)  To summarize, the question posits a block in contact with a compressed spring on a frictionless surface.  The spring is released from rest.  At the spring's equilibrium position, the block comes off the spring onto a rough surface.

The primary experimental challenge is to produce data verifying the answer to part (a)(i): Sketch a graph of the block's kinetic energy as a function of position.  In particular, we need to show the correct shape of the graph before and after the block reaches the spring's equilibrium position.


The theory: Okay, obviously the kinetic energy increases to a maximum at the D = 0 equilibrium position, then decreases back to zero, because the speed increases than decreases.  The functional form of the graph is the complicated bit.  It's easiest to see through an energy approach:


Before D = 0, the potential energy of the spring is given by (1/2)kD2.  This means the potential energy drops to zero as D2, i.e. parobolically.  Since the sum of kinetic and potential energy must be a constant value on this frictionless surface, the kinetic energy curve must be an upside-down parabola.

After D = 0, the block loses kinetic energy because work is done on the block by the friction force.  Work is force times distance traveled parallel to the force... that is, linear with distance.  Thus, the kinetic energy drops linearly until the block stops.

The experiment: You'll need a compressible spring, a way of keeping the block moving in a straight line, and a device to record speed as a function of position.

(You DON'T need to worry about the "frictionless" surface before D = 0.  The shape of the graph is still parabolic, even if there's work done by friction before the block is released.  Why?  Because both the with- and without-friction mathematical functions -- (c - kD2) and (c - fD - kD2) -- are parabolic.)

My students and I flipped a PASCO two-meter track upside down to find a groove just about the right size to fit one of those wooden felt-covered friction blocks.  We stuck a Vernier sonic motion detector in the groove about a meter away from the track's edge.  The detector was set to acquire data at the highest possible frequency - I think we used 50 points per second, but I'm not entirely sure.  At the edge of the track, we pushed the block against the spring and let go.  The spring uncompressed, the block slid toward the clicking detector. 

Next came some serious data presentation work.  We had to figure out how to use the Vernier Labquest to graph calculated data columns - it only automatically produces distance, velocity, and acceleration data.  But this is a matter of programming, not physics.  We got the device to output (1/2)mv2 on the vertical axis; on the horizontal, we used a subtraction function to adjust the distance from the detector so that "zero" represented the location of the block with the spring uncompressed. 

And sure enough... though the function looks choppy because we only have one point every 0.02 s, it's the correct shape:


As an improvement, a student suggested using a PASCO smart cart on a track, attaching a crumpled piece of paper or similar to the front of the cart to produce some frictional drag on the track.  The motion encoder in the smart cart's wheels can take more frequent (and more precise) data than the sonic sensor.  However, I don't have enough familiarity with the sparkvue interface to create the derived graph from the raw data.  If you do, please try the experiment and email me the results - I'll post them here!

17 December 2018

Ask not what your students *should* do. Ask what they *do* do.

I was in high school marching band.  We won the Kentucky state title in my senior year.  Please hold your applause.

"I'll bet youall practiced a lot," you say.  Sure: we had summer band camps, and after-school practices equivalent to those of varsity athletic teams.

So, yes, the volume of practice time was certainly helpful to our success.  Nevertheless, we routinely defeated other bands who practiced similar hours.  How we practiced was as important as how much we practiced. 

Two questions to ask about our band director's pedagogy:

Question 1: Should voluntary participants in an elite high school ensemble, for which we were graded and earned academic credit, be expected to do independent, self-motivated practice?  Should band members come to rehearsal with their parts mastered, ready to work on fine tuning and advanced ensemble work?

Answer: Yes.

Question 1a: In actuality, out of 50 band members, how many dove into said independent, self-motivated practice?


Answer: Two.  On a good weekend.


Importantly, the band director didn't nag us about practicing our instruments on our own time.

Instead, he worked with us on difficult passages during rehearsals.  He showed us techniques that would help us improve.  So, using the regularly-scheduled rehearsal time alone, we got pretty good.  When he did need us to do some practicing outside of rehearsal time, he'd give specific goals -- "on Monday, you must be able to play measures 98-116.  I'll pick a couple of you randomly to play for all of us."  No nebulous and shaming "make sure you practice this weekend!" for us.

Question 2: Should the participants in the school's highest-level ensemble, one that expects to be competitive with the best bands in the state, have mastered basic skills prior to important mid-year rehearsals?  Should the participants retain training from practice to practice, from week to week, such that the director does not need to re-teach basic skills and already-taught elements of the competition show?

Answer: Sure.

Question 2a: In actuality, how well does the band retain skills and show content if they're not reinforced on a very regular basis after band camp ends?

Answer: Not well at all.

The band director didn't nag us about retaining skills.  He didn't complain that we should have learned these things by now.  Instead, he drilled us such that we didn't forget.

Every practice, all season, began with marching fundamentals - everyone in a block, at the command of the drum major performing a number of basic maneuvers, all the while the director and his assistants watched like hawks for uniformity of technique.  Then came the musical warm-up, reinforcing basic skills - perhaps today we did an exercise based on the E-flat scale, maybe tomorrow was a tuning/blending exercise, the next day rhythm or embouchure drills. 

This all took at least 30 minutes of a two to three hour practice.  And was worth every moment.  (It was, honestly, a bit drudgerous.  However, the first 30 minutes of practice became ritualistic, such that we felt a hole in our collective soul on those rare occasions when we didn't do fundamentals and warm-up.  I recall a couple of occasions when the upperclassmen practically demanded to start practice the "right way" when someone proposed to skip warm-ups.)

Next, we'd re-teach pieces of the competition show in small chunks on a regular basis.  By season's end, each segment of the show had been taught in the summer, then re-taught two to three times.

Physics teaching connections:  

(1) While students in an AP -- read "college level" -- class *should* be able and willing to put in many hours of engaged homework time each week, in practice they're not.  It's our job to design the course with expectations about out-of-class work which students can and will meet.  Then it's our job to find a way to use class time to develop physics skills such that students can make the best possible use of what time they do devote to out-of-class study.  We need to solve problems in-class.  We need to teach how *not* to ask for help fifteen seconds after reading a problem.  We need to teach how to start an unfamiliar problem, and how to collaborate with classmates to communicate understanding.  

(2) While students in an AP class *should* be able to retain basic facts and problem solving techniques from week to week; while elite-level students *should* come to our class with algebra skills; fact is, they don't.  It's our job to design the course to teach/reteach even things they should have already learned.  Give fundamentals quizzes.  Don't give unit tests, give cumulative tests.  Assign problems that require students to circle back to already-mastered material.  

Look, if you know anything about my classes, you know that I'm as far from a fluffy no-standards teacher as it's possible to be.  Yet teaching rigorous physics doesn't mean we have to expect monkish devotion from our students.  When we complain to our students or our colleagues about how the kids just aren't studying like they should, we alienate the audience.  Meet the class where they are, not where they should be, and everyone will be happier and more successful.  Yes, of course require the class to know and use appropriate skills as the year progresses... but continue to teach those skills in context, too, so that even those with weak backgrounds and minimal out-of-class devotion can eventually catch up.

09 December 2018

Hints for preparing students for a physics presentation

I'm thrilled when I hear about physics teachers using student presentations and formal student-led discussions as teaching tools.  Students should come out of our classes with the ability to explain physics orally as well as in writing.  But that's easier said than done.

Think back to your high school (or college) days.  How did you feel about listening to your classmates when they did formal presentations?  (Not how did you feel about giving presentations -- since you became a teacher, you might have liked that just fine.)  Did you look forward to presentation day?  I doubt it.  Possibly you were neutral, taking the "at least we don't have to listen to the teacher for an hour today" approach.  

More likely, you dreaded those classes.  Student after poorly-prepared student with minimal public speaking skill, some reading (badly) straight off of hastily-written notes.  Aargh, it was academic torture.

So don't make your own students suffer.  If you're going to do formal presentations, prepare for them with tremendous care and detail.

Set time limits, and enforce themSet a timer on your phone with a loud alarm at the end.  The students must know going in that if the buzzer goes off before they're done, they're done anyway.  No pity, no remorse, no exceptions.  Don't yield to the temptation to allow a student just to finish a thought, or to give them just a bit more time because they didn't quite get to the important part of the presentation.  You're teaching a life skill here.  Let them fail - then next time they probably won't fail.

Presentations can be very, very short and still be useful.  Even a long-term project can often be summarized in three minutes.  In fact, it is a valuable skill to learn how to communicate complicated ideas in such a short period.  What makes student presentations so painful is often the attention they give to irrelevant details, while the audience rolls its collective eyes saying "arrgh, get to the point."

Do not allow powerpoint.  Slides are too often used as a substitute for substantive communication.  See also this post. 

Practice, practice, practice.  Ideally, you'll go through the class for several days before the presentations, watching each student in turn and giving feedback.  You'll also have students giving their presentations to each other for days before the actual event, giving each other feedback.  Make a video recording of students speaking - it's painful but important for students to see themselves droning on without eye contact, repeating themselves without communicating anything important.  Force students to see these mistakes while they still have the opportunity to correct them before presentation day.

If nothing else, assign presentations for homework - require three dry runs in front of another human.  I mean, you know darned well that typically students try to wing presentations without appropriate preparation.  So require that preparation in and out of class.  Give the students a homework sheet that asks for the signature of the person who watched each presentation.  If each presentation is only three minutes without powerpoint, that's not a burden at all - it's a ten minute assignment.  

Too many teachers throughout the years have assumed that their students know already about basic speaking-to-an-audience skills, have assumed their students will be self-motivated to practice and perfect their presentation.  Then when the horrible presentation starts, everyone is embarrassed, just like when the kid at the talent show didn't practice his clarinet solo and now has no choice but to honk on.  It's our job to insist on the practice that we know teenagers won't likely do.  It's our job to teach the speaking skills that students haven't internalized yet.  

Eyes up.  The first thing I do in practice is start making faces at the students who stare at the whiteboard or at their notes instead of making eye contact with the audience.  Pretty soon, the whole class is helping each other keep their eyes up.  This good posture subsequently encourages students to speak naturally, telling their story to the audience rather than talking to themselves.

Who is the audience?  It's not good enough to tell the class "you will be speaking to your classmates and two other science teachers - all of whom are familiar with the first-year physics that you have learned."  It's not even good enough to explain what that means in front of the class.  You must allow the students to make mistakes in their assumptions about the audience, and then learn from those mistakes.

For example, a student will write an equation like d = vt, then spend 45 s of their three minutes umming and hmmming through an explanation of what d and v and t stand for.  It's never occurred to this student that the audience is familiar with this equation. That all they need to say is "We use d = vt because the cart's speed is unchanging." That the audience is more interested in the physical prediction made by this equation, and how that prediction is verified experimentally.  

So tell this student right now!  Right now, your feedback is in context.  You're not droning on about something that your quite intelligent and experienced-at-school student thinks that she already knows.  You're gently correcting a serious error immediately after it's made.  Your student can't tune you out, or say to herself "whatever, I know that."  She's just screwed up.  If you speak firmly and with love, showing with your whole being that you are helping prevent a mistake on a bigger stage, your student will listen, and appreciate your helpful feedback.

And the message will spread throughout the class.  The student you just critiqued will, in turn, share that feedback with the person she watches for practice.  And everyone will get better, as a team.