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26 May 2015

What do I do at my AP Physics 1 (and 2) Summer Institute?

You can see in the sidebar the dates and locations of my 2015 summer institutes.  I'm sometimes asked what goes on at these.  Here you go...

On the first morning, we go through the details of the AP Physics program.  We talk about the topics covered, the extent to which each topic is covered, the structure and style of the exam, how the exam is constructed, and all sorts of information that College Board "insiders" know.  Plus, we show how the new Algebra-based exams are in no way condusive to traditional plug-and-chug methods, and discuss simple ways of adapting to the shining new era in AP Physics.

Next we discuss ideas about integrating AP Physics into teachers' specific school cultures.  How do you sell the course to students, parents, and administrators?  How do you teach AP Physics when your school won't let you [foo] or when they make you [bar]?  What overriding course structure will work for you personally?

On the first afternoon, I present my first few AP Physics 1 classes exactly as I present them to my own class.  These include quantitative demonstrations with equilibrium.  I show the interactive performance, the problem sets, the quizzes, everything.  The goal is to see how I cover new topics concisely, in a manner that causes students to (usually) pay attention; and how the homework and quizzes reinforce the class material.

On the second day, I begin by "going over" a homework assignment in a brief and interesting fashion, focusing on physics rather than on awarded points.  We also will discuss daily grading of student work, and the many alternatives for regular evaluation.  I show more quantitative demonstrations, including on topics beyond mechanics.  We discuss sources of activities, problems, and information.

In the afternoon, we do one of my typical extended laboratory activities, in which students collect data, linearize a graph, and make a quantitative prediction or determination based on the graph.  We close with a discussion of assessment methods, and how there's not such thing as "formative" or "summative" assessments -- everything in life is a test.

On the third day,  I show some alternatives to my bog-standard quantitative lecture-demonstration classes.  We do an activity with Direct Measurement Videos.  We do "in-class laboratory exercises" in which students make predictions and experimental measurements to solve problems at their own pace.  

The afternoon session is devoted to electronics.  This is one topic I teach as nearly-pure modeling; we do a laboratory activity that also serves as my students' entire introduction to circuits.  We follow up with TIPERS activities, which we set up experimentally as in-class laboratory exercises.  And finally, I show how my bare-bones-basic introduction leads eventually to sophisticated, AP-level understanding by "translating" into AP language.

On the final day, we talk about the different levels of physics teaching, and how people adapt their presentation from conceptual, general (i.e. Regents), college-prep, or AP Physics C.  We do any activities or demonstrations that participants want to see but we haven't yet gotten to.  We brainstorm and try some "open inquiry" style lab activites, and we discuss how structured lab work leads naturally, after time, to unstructured creative lab work.  

Finally, we do a mock AP Physics reading.  I will be a table leader for AP Physics 1 problem 4 -- that's the paragraph-response item about why two balls hit the ground at the same time, even though one is dropped while the other has an initial horizontal velocity.  We will have authentic student samples.  I'll train participants to grade these just as if they were present at the reading itself.

After the institute each night, I make myself available for physics (or non-physics) conversation over dinner.  Participants are welcome to ask their individual questions over burritos and/or french fries.  I meet a lot of great folks this way through the AP Summer Institutes; know that I don't consider my job done when we leave at 4:00 or 5:00 each day.

And after the whole thing is over, you're encouraged to contact me.  You will have a CD of all of my course materials from all of the different-level courses I've taught.  It will take you years to sort through this material.  When you have questions, you're always welcome to ask.  Sometimes I'll point you to a post on this blog; sometimes I'll answer as a blog post, so others can see the answer.  

Physics teachers are a different breed.  We need to hang together, to share our ideas, our frustrations, our succcesses.  It helps us all so much to hear how many of us face similar challenges, and to hear how others have conquered those challenges.  And it's likely that no one else at your school has any clue about what you do.  So come to an APSI.  Join other folks who truly understand you and your job.  You may be the only AP Physics teacher at your school, but there are a bunch of physics teachers nationwide who can help you, and whom you can help.  Join us.  I can't wait.

[And soon I'll post about what we might do at my free non-AP "Open Lab" at Woodberry this summer.]


11 May 2015

2015 AP Physics 1 solutions -- my draft version

The AP Physics 1 exam was five days ago.  Click the link to see the free response questions.  

I solved the problems last weekend.  You may see what I came up with here, via PGP-secure.  This link is teachers only.  Students, if you want to see my solutions, you'll need to ask your teacher for access.  Teachers, if you don't have a PGP-secure account, you should -- instructions are posted on the website.  The site has a humongous volume of fantastic materials for all levels of physics teaching.

What about my thoughts on the exam itself?  Well, it was exactly what we expected.  No explicit calculations.  Lots of explaining.  Three mechanics questions, one circuits question, one waves question.  It will reward students who know how to justify their answers with respect to facts, equations and calculations.  It will destroy students who try to plug random numbers into random equations.

 Problem 1 is a great and straightforward question.  I like the explicit demand that the free body diagram be drawn to scale -- the tensions are equal, and less than the big block's weight, and more than the little block's weight.  Both parts (b) and (c) require an understanding of treating the two or three blocks as a system.

Problem 2 requires that students interpret circuit language.  I'm sure I'll post on this eventually... I began the circuit unit with what I called "nonrigorous" definitions of voltage, current, resistance, and power.  Once we could memorize and calculate using VIR charts, and once we had plenty of experimental experience, we learned the AP language:  energy per charge is voltage or potential difference, energy per time is power, charge per time is current.  If my students made these connections, they should have done just fine.  In fact, I even did that same experiment in class in January where we see whether a bulb is ohmic or not.  I can't guarantee that my students remembered the experiment, but...

Problem 3 is somewhat improved over previous attempts at the qualitative-quantitative translation.   I like that there was only one student's reasoning to deconstruct.  My class said they felt like they were repeating themselves over and over -- the distance square term in the spring energy equation means that doubling the distance compressed quadruples the energy stored.  As long as they followed directions, and made explicit reference to their equations and what those equations mean, they will hopefully be fine.

Problem 4 should have been seven free points for all.  In fact, we are giving this problem to our regular 9th grade conceptual physics class to see how they do.  We think they'll ace it.

Problem 5 is my favorite.  It's basically a violin -- you have to use different gauges of string in each of the strings on a violin.  I love the "will the graph be linear" question.  And the last question simply asked to locate the antinodes; once again, students had to interpret AP Physics 1 language, but the released materials have been pretty clear that "average vertical speed of a point on the string" is something students are expected to understand.

Remember, my solutions are unofficial, and may even be incorrect.  I guarantee that I would have gotten a 5 on the exam, but not that I get 100%.  I don't know how the grading will work (yet), either -- perhaps some of my phrasing won't earn full credit.  We'll find out in a few weeks.


10 May 2015

Astronomy Teaching Resource from University of Nebraska

The UNL astronomy department freely provides
Flash simulations like this one
I've often taught a two to three week astronomy unit toward the end of the school year.  I cover basics of earthbound astronomy, most of which are tested on the New York Regents Earth Science exam: motions of the earth, the solar system, phases of the moon, how do we know the distance to stars, and so on.

This material is fun, but was always difficult to explain.  I did a lot of, "okay, pretend this basketball is the sun, and this Dunkin Munchkin is the Earth."  I used the computer program Starry Night to show what the stars and planets look like on any date, at any time, at any location on earth; that held attention well.  But for three-dimensional geometry that requires a point of view off of Earth, I had to do a lot of imagining with my students, with mixed results.

But this year I discovered this website from the University of Nebraska.  It includes a treasure horde of Flash simulations, most of which are exactly the kinds of ideas I had to explain using basketballs and flashlights.  On the first day of my unit, I used the meridional altitude simulator (screenshot above) to show how to determine the height of the sun at noon at any latitude on any day.

Not only does the Flash animation do instantly what used to take me a full minute to draw poorly on the board, but the simulations are freely available to my students outside of class.  Astronomy discussions are tough to sit through.  In astronomy I can't do the kinds of experiments I do in mechanics -- we can't just up and travel to midnight on the winter solstice in Costa Rica; we can't just run time fast and measure the altitude of Arcturus at midnight as a function of the date.  So students have to listen to me and each other, and they have to really pay attention to lecture and discussion.  That's not easy on a beautiful spring day.

So I can assign the same types of homework questions I have for years, but I can give students these simulations to play with at home.  Then, if I don't do enough drill and practice with the exact skills I want students to acquire -- or if I don't explain well some three-dimensional abstract celestial geometry -- my students have a resource that will show them how the universe works much better than either I or a textbook ever could.  Thanks, UNL.

04 May 2015

My summary list of all topics for AP Physics 1

The College Board used to publish a delightfully simple two-page guide to the AP Physics courses.  It included a list of common topics -- each expressed in a few words -- a check box to indicate whether it was covered on the AP Physics B or C exams, and a percentage guide to how much of each exam involved each unit.  Granted, teachers had to investigate further by reading many historical exams to understand exactly what aspects of each topic was covered.  But the two-page summary was a critically useful starting point and quick reference guide.

When the education professors got their paws into AP Physics 1, the result was a pretty danged excellent exam... as well as impenetrable and poor communication about what the exam covers.  The College Board will argue that the 150 page "curriculum framework" provides excruciatingly exact detail about the topics covered, the depth of coverage, and the tasks students will be asked to perform in conjunction with each topic.  That's true.  It's also true that no one really reads the Bible, a dictionary, or an atlas cover to cover and remembers every detail.  The curriculum framework is a reference work, not a novel.

The College Board never released an official summary guide.  So over the course of the year I've made my own, UNofficial summary guide to topics on the AP Physics 1 exam.  (I swear, it's two pages on my computer in MS word... google docs doesn't upload the two-column formatting.)

I've listed all the topics below.  Some important disclaimers:

(1) This is NOT a College Board Approved list!  It's my own work, based on my own reading of the curriculum framework and the released exam.

(2) It is NOT comprehensive.  That's the point, see?  If you want comprehensive, read the encyclopedia curriculum framework.  Please do not complain to me that my list didn't cover a detail that you left out of your course.  (Those types of complaints are possibly why the CB didn't create a topic summary in the first place.)

(3)  This list reflects my prejudices and topic coverage.  If you find something big and important that I've left out -- and you will -- please comment or email me.  I may add some things.  On the other hand, you might think that something I've included is too detailed to be worthy of inclusion, or is too confusing for an overview.  Please tell me that, too.

Okay, here's my list.  On the last day in class, I spend 30 minutes going through it rapid-fire, explaining what I can and answering questions.  Post a comment telling me how you use it.


Position-time graphs
Velocity-time graphs
Algebraic kinematics
Projectile motion

Forces and Newton’s Laws
Force and Net Force
Solving problems with forces
A free-body diagram includes:
Mass and Weight
Normal force
Friction force
Inclined Planes
Newton’s Third Law
gravitational force
gravitational field
Gravitational and inertial mass
Uniform circular motion
Force of a spring

Impulse, momentum, collisions
Conservation of momentum in collisions
Center of mass

Work-Energy Theorem
Definition of Work
Equations for different forms of energy
Vertical springs
Rotational KE

Simple harmonic motion
Wave definitions
Equations relating frequency, period, wavelength, wave speed
Transverse/longitudinal waves
Doppler Effect
Standing Waves

N2L for Rotation
Relationship between angular and linear motion
Rotational Inertia

Angular momentum
Angular “impulse”

Smallest possible charge
Charge is conserved
Coulomb’s law for force between charges

Non-rigorous definitions of voltage, current, resistance
Rigorous definitions of voltage, current, resistance
Resistors in series
Resistors in parallel
Ammeters and Voltmeters
Power and Brightness
Kirchoff’s loop rule
Kirchoff’s junction rule

Resistivity is a property of the material a resistor is made out of
Equation for the resistance of a length of wire

Open Lab 2015: July 19-21 at Woodberry Forest School.

It was successful last summer, so we'll do it again -- Open Lab 2015 at Woodberry Forest will be July 19-21.  Here's the official announcement, similar to last year's:

I spend much of my summer running official College Board AP Summer Institutes. I encourage you to join me for one of these... the dates and locations for 2015 are posted in the sidebar.

While I love AP Physics, and I love the Summer Institute format, I also recognize that there's more to physics teaching than can be discussed in a week devoted specifically to the College Board's courses. What about conceptual physics? General physics? Research? And how about college-level physics that doesn't correspond to the new algebra-based AP exams? These topics deserve some attention in serious professional development workshops.

On July 19-21, 2015, I invite you to Woodberry Forest for a Summer Institute that is NOT exclusively devoted to AP physics. I will share my own materials related to non-AP courses; we'll talk about and actually do some activities and laboratory work focused at all levels of physics, from conceptual to research and everywhere in between.

The best professional development gets interested teachers together, in person, and then facilitates shop talk.  Last year we had ten teachers participating, of all experience levels, and from six different US states.  My goal is that you should be able to have good discussions, with me and with the other participants, about any physics teaching related questions you might have. Hopefully we'll all leave on Tuesday the 21st with a bunch of new ideas to try out. 

I'll post more logistical information shortly. For now, know that there is no charge for the open lab, but there's no grant money, either. You'd need to pay for food and lodging. Arrive on Sunday midday; we'd have a late afternoon formal* session followed by dinner together and an (informal) evening "session" at my house. We'd work all day on Monday, and until mid-afternoon on Tuesday. You'd want to stay Sunday and Monday nights at the Holiday Inn Express in Orange, VA -- that's a five-minute drive** from campus. We'll eat together in Orange for meals, with Sunday night's dinner at my house sponsored by Woodberry Forest's science department. As those of you who have been to my summer institutes know, just being around other physics teachers is professional development, whether we're in the lab, walking around campus, at dinner, in the pub, etc.

* (or as formal as anything I do ever gets)
**(Or a 1.5 hour walk, or a 50 minute jog... I've done all of these.)

There is no "registration," -- just tell me you're coming and make a hotel reservation. Spread the word. 

01 May 2015

Taft's simulation labs: using Wally the Astronaut for AP Physics 1 prep

Last week California physics teacher Eric Plett sent me a link to Taft School's simulation labs.   I was immediately impressed.

Phet applets have been my venue of choice to send students to find good physics simulations.  I like Taft's even more, because they are set up such that multiple parameters can be varied in different ways.  A single application allows for multiple experiments, multiple investigations, and lots of interesting physics. Even though I am emphatically NOT a simulation person -- I believe in hands-on laboratory work with real, live equipment -- I nevertheless see the value in computer simulations.

The link above is to the site labeled "Ideas to review for the AP Physics 1 test."  There are other experiments, available at the "lab simulations" tab at the top of the page.  Since I've already done more live, hands-on experimentation than I can even recall right now, I was happy to try using one of these simulations for AP exam review.

Today in class I gave this six-minute quiz.  I described the "Wally the Astronaut" simulation, shown in screenshot above: Wally's rocket applies a steady force for some distance, then he goes through the red photogates at constant speed.  The quiz asks for a derivation of the relationship between the distance d through which the force is applied and the time t spent in the photogates.  This is a nice two-step derivation, requiring both the work-energy theorem AND basic kinematics.  The qualitative-quantitative translation question on the AP exam will similarly demand that students use mathematics to combine multiple concepts.

Next, I asked students to sketch a graph of d vs. t; and to propose a new graph that would be linear.  I don't know whether AP Physics 1 will have the same emphasis on graph linearization that AP Physics B did.  But my students are prepared, regardless.

Finally, I discussed the quiz, and sent the class off to do the "experiment" on their computers.  This final attachment is the lab assignment which is due on Monday.  As with most experiments, I have students make the linear graph, find a slope, explain (with both calculations and words) the physical meaning of the slope, and use the slope to determine an interesting physical quantity.

Note how many different approaches you could take to this simulation!  Because the force and mass are both variable, as well as the distance through with the force is applied, you have many, many possible experiments available.  I chose to do the d vs. t version, but I'd love to hear other ideas.