Saturday, June 18, 2011

Observations of a first-time AP exam reader shared on the AP Physics EDG by James von Steen, physics teacher at Southwest Guilford High School in High Point, North Carolina. His note is reprinted here with the author's permission.

It's important to note that the author's intent is not to deride test-takers for common mistakes, but rather to describe the observations he made as a first-time AP Physics exam reader (grader).
After a 5 year wait, I final received the opportunity to become an AP reader. My primary goal was to learn as much as I possibly can to become a better teacher. Here are things I noted.

1. A lot of students thought that work is always positive (never negative).

2. A lot of students thought W = F x t , W = F / d , W = F x v and F = mat.

3. If a student put down the correct numerical answer, but showed no work, they could get 0 pts and 1 pt at most.

4. A student could have math errors and still get maximum points.

5. On an FBD, if the directions say “on the dot below” draw the force vectors …., If the student draws force vectors that don’t touch the dot (even though they are correctly labeled and pointed in the correct direction), they could lose credit (I learned this one at the lunch table).

6. Readers don’t like grading the lab question.

7. I’m going to tell my students when “Justification” is requested, use formulas and calculations to justify your answer as oppose to words. The more words they write the more likely the reader is going to over look a correct answer. Example: W = F x d = -15 J (easy to spot and give credit) as oppose to ”Work equals forces times distance which will be a negative numbers” (hard to spot especially embedded in a lot of text). I looked back now and wonder if I missed giving some desiring students credit.

8. Don’t use the word “it”. I don’t know what “it” is. I saw students write “it is decreasing”. I don’t know if “it” meant acceleration, velocity or my bank account after the children are born.

9. A lot of students thought work was a vector.

10. Watch out for the decimal point in the given. The problem was given 0.40 kg and a lot of students wrote F = ma = (4)(2) = 8 N and missed an easy point.

11. “Check” the box(es). Some students didn’t do any work but checked the correct spaces and got credit and (sadly) one student got no credit because he/she check no boxes even though they stated the correct box to be checked and had the correct justification (we have to go by the rubric).

12. I thought that the students didn’t have to memorize any numbers, but the only way to answer the very last problem of the exam 6. d) ii) is they had to memorize the wavelengths of visible light. I was told it is in the “acorn” book, but I couldn’t find it. Which makes me think that there are other numbers out there that my students are require to memorize.

13. It looks like the AP Physics redesign will be a step backwards. I didn’t hear anybody liking it public or privately. I’m luckier than most. I’m able to get the whole curriculum in but my students will take 2 exams for 6 hours instead of 1 exam for 3 hours (and yes they paid for both). I can see the redesign killing some AP physics programs and overall less students taking the exam.

14. The food was “ok” (not as great as I heard it was). I got tired of recycled green beans, lettuce and potatoes every day.

15. I met a lot of smart people that I learned from. I hope they ask me back next year.
Responses to von Steen's post indicated some variation of interpretation among readers. But the variations were relatively subtle.

You tend to see things when you're a wide-eyed first-timer that you don't always see when you're a sage veteran. And this first-timer was willing to share. Students might appreciate these insights as they go into the exam in May.

Thursday, June 16, 2011

Pool Cubes 2: Buoyancy - new PhET activity

PhET has added fluid statics to their physics repertoire. I wrote an activity for their Density sim. But it needs a bit of polish, so I'll post that one later. In the meantime, enjoy this tech lab that uses the new PhET Buoyancy sim.

Pool Cubes 2: Buoyancy (PhET page)

The purpose is to investigate the nature of the buoyant force and to see the role it plays in determining whether or not an object floats. The ability to use a variety of objects in the liquid and to vary the density of the liquid makes a number of scenarios possible. Real labs are great, but do you really want to deal with a broad variety of liquids (oil, gasoline, etc.) in the laboratory?

I wrote the activity for my AP Physics B students, so it gets mathematically robust toward the end. Nothing they can't be able to handle with a bit of algebra.

The groovy "3-D" graphics and textures used in the new sim are great. The science has to be right, of course. But once the substance is established, why not have some style?

AAPT workshop and contributed talk

If you're headed for Nebraska to frolic with fellow physics friends this summer please come see me! The American Association of Physics Teachers will be meeting July 30-August 3 at Creighton University and the Doubletree by Hilton in Omaha.

My friend, Matt Lowry, and I will be presenting "Skepticism in the Classroom," W42, Sunday, July 31 from 1pm to 5pm in HLSB 523. We will present a variety of lessons, appropriate for the physics classroom, that focus on the skeptical and critical thinking nature of science. Some lessons involve obvious physics content; some bring in examples from the real world. Participants will leave with ready-to-use lessons (video clips and student worksheets) and resources designed to bring healthy, scientific skepticism to their classrooms. Topics will include firewalking, ghosts and angels, balance bracelets, the credulity of local media, and more.

I'll be presenting a talk on Tuesday, August 2 at 2:15pm in the SS Ballroom F. It's part of session EJ: Recruiting Students to High School Physics, which begins at 1:15pm. My presentation is EJ03, "One Mad Man's Campus Campaigns." The abstract: In good times you should advertise, in bad times you must. As the son of an advertiser and a marketer, I have always valued advertising as a recruitment tool. As a high school physics teacher, I have been motivated to maintain or increase my "market share" each year. I have used "dog and pony shows," personalized direct mail campaigns, and a variety of flyer and poster designs. I will detail the relative efficacy of the various campaigns and share specific designs and slogans I have used over the years.

I hope to see you in Omaha.

Wednesday, June 15, 2011

Power Force is brought to you by the number "8ight"...

and the letters BS.

When it became clear that people would fork over cash for some mylar glued to a rubber band, entrepreneurs wanted a piece of the action.

The proprietors of Power Balance proved there was a gold mine in fraudulently marketed wristbands. The company raked in millions using celebrities to promise customers that their product would enhance power, balance, flexibility, and endurance.

How can a wristband do this? It can't. Power Balance claimed that a frequency of 7.83 Hz was embedded in the band's hologram, and that 7.83 Hz was the frequency of the body's energy field.

This is all very impressive, except that the body has no "energy field," so it doesn't resonate at 7.83 anything. And you can't "embed a frequency" in a hologram if you wanted to.

The trickery used in the demonstrations showing the efficacy of the wristbands is well understood. (A complete take-down lesson plan with videos exposing the trickery can be found at Skepticism in the Classroom.)

Take-downs and exposés aside, Power Balance has raked in so much cash they could afford to purchase the naming rights to Sacramento's Arco Arena, now known as Power Balance Pavilion.

The copycats at Power Force wanted to cash in on the boom. They upped the ante by securing licensing agreements with major colleges and universities. So their impotent bracelets bear CU's iconic Buffalo logo and Berkely's "Cal."

And Michigan's block M. My own alma mater bit on this BS, sacrificing integrity for the promise of a shekel. Power Force can delight in having the tacit approval of major research institutions—institutions with Nobel laureates in science.

Power Force doesn't claim its wristbands harness the power of frequency-embedded holograms. No, they leverage the magic of "negative ion technology." They don't detail exactly what negative ion technology is; they presume buyers know that it's something real.

If you visit the Power Force website, clicking on the "Power behind Power Force" tab gets you to this:

Power Force Apparel powered by 8ight is the official sports band provider for your favorite colleges and universities, providing officially licensed products bearing each school's logo and colors.

While Power Force makes no medical or scientific claims, negative ion technology can be found in all Power Force products. The pride that comes from athletes and fans supporting their schools with Power Force products is beneficial to everyone that wears them.

Support your school and your team 365 days a year with Power Force Apparel Powered by 8ight.

One sees the "Powered by 8ight" tag line all over the Power Force site. What is 8ight? Take a look. Mind you, no medical or scientific claims are made. None whatsoever.

If you can watch that without throwing up in your mouth, I salute you!

So which institutions of higher learning have traded their integrity for snake-oil cash? In the Big Ten, it's Illinois, Michigan, Minnesota, Nebraska (!), Northwestern, Penn State, Purdue, and Wisconsin. Somehow Indiana, Iowa, Michigan State, and Ohio State resisted the merch-licensing instinct on this scam.

In the Pac 10, the suckers are Arizona, Arizona State, California, Oregon, Oregon State, Washington, and Washington State. Kudos to UCLA, USC, and Stanford for having self-respect.

A complete list of NCAA sell-outs can be found at Power Force's catalog.

I no longer support my alma mater when they reach out for donations. I kindly assure them (via their telemarketers and direct mail solicitations) that they'll earn far more money from their deal with The Devil Power Force than I could ever hope to give. No doubt this paints me as a miserly curmudgeon. I'd love to renew my support, but I can't while Michigan partners with an outfit of charlatans.

By the way, nothing in this post should be interpreted as libel toward anyone or anything. I am powered by skepticism and critical thinking.

Why I am Excited about TAM Vegas 2011

James Randi Educational Foundation president, D.J. Grothe details his enthusiasm and anticipation of the upcoming TAM9 From Outer Space. It's gonna be big, and it's gonna be good.

If you're on the fence about attending, read his post.

Sunday, June 12, 2011

Paul Hewitt visits Rio Americano

The educational value of the last day of school is rightly debated. It's the day after graduation; seniors have been gone for several days. Final exams are over. There is no new material to teach or learn. Options for disciplining misbehavior are limited.

We spend years making our students smart, so they realize that consequences for unauthorized absence or failure to keep to their daily schedule are minimal. The result is that many students do not show up, and the ones who do feel entitled to some degree of off-task behavior. Teachers the foil off-task behavior potential by not offering a task to stray from.

Friday, June 10, however, was the best Last Day of School we ever had in the history of Rio Physics. Conceptual Physics author, Mr. Paul Hewitt came for a visit! In the casual setting of the day, he answered student questions, offered sage advice to students, posed for pictures, and signed autographs (with cartoons to boot).

We were able to visit physics colleague, Mrs. Lucy Jeffries, on her last day at Rio and say "hi" to the principal, Mr. Brian Ginter, and vice-principal, Mrs. Vanessa Adolphson as well.

Hewitt was welcomed by physics students who appreciated his textbook and saw him in action in his Conceptual Physics Alive! videos. I will freely admit bias in this matter, but I cannot imagine the author of any other textbook used on campus being given so enthusiastic a reception had they paid a visit. If I'm wrong, please correct me in the comments. Non-physics students were coming in to get pics and autographs!

Hewitt had a great time at Rio. He found the campus to be beautiful and the students to be delightful.

One student put it best in the caption of the Hewitt "groupie" shot he immediately posted to his Facebook profile. As if to chide those who skipped or slept through Hewitt's visit, he posted his prize pic with the note, "You so jelly I could make you my lunch!"

If you're a student who got a shot with Mr. Hewitt, send it to me and I'll add it to the album linked below.

Hewitt at Rio photos at Flickr.

2011 class portraits

Here they are: the class portraits of Rio Phyz 2011.

1st Period AP Physics

2nd Period Physics

4th Period Physics

5th Period Physics

6th Period Physics

The full Flickr album is here.

The Go-Girls also produced a video goodbye featuring 6th period students. I'm pretty sure it was recorded while I was out on federal jury duty.

I must hasten to point out that many of my students would disagree with the sentiments expressed in the video. But that doesn't diminish my delight of the video-gift that "db" is.

Wednesday, June 08, 2011

Zangle in Chapter 11 bankruptcy?

How did I miss this news?

I'm not dancing a jig, mind you. I like Teacher Connection to some extent. Partial kludge, but it's operationally functional. Not prone to crashes or downtime.

Gradebook, however, is an unforgivable kludge that I find completely unusable.

My sense is that day-to-day operations will continue without interruption.

Still though.

Tuesday, June 07, 2011

Hula Hoop-cam: The world goes for a spin

The Go Pro is a small, light-weight camera capable of still photography and video capture. Here's what happens when you attach one to a Hula Hoop and attach the Hula Hoop to a skilled practitioner. Those inclined toward motion sickness should probably not go full-screen on this one. Everyone else? What are you waiting for!

Gyrational hula spins to PTSOSer Zeke Kossover and Exploratorium guru Paul Doherty.

Sunday, June 05, 2011

The Greatest Music Video Ever Made

If you haven't seen the video, you probably should. Roger Ebert dubbed it "The Greatest Music Video Ever Made." That's a thumb's way up from the celebrated movie critic.

There were certainly artistic reasons for using Don McLean's classic, "American Pie." But some readers might associate that title with an endless series of teen movies bearing the same name. That's OK. The writers and director responsible for American Pie hail from East Grand Rapids (Gerald Ford's old stomping grounds). In the films, their high school goes by the name "East Great Falls" to protect the innocent. The movie was shot in southern California, of course. The high school shots were filmed at Robert A. Millikan High School. Physics Connection!

If you think the GR Lip Dub video is a frivolous follow-shot, that's because you didn't watch it through to 6:24.

According to my test-marketing in the Sacramento high school demographic, the "I met a girl who sang the blues" boy is surprisingly cute. Until I showed this video, I was the sole representative of what people from Grand Rapids look like at my school. I assured my students that there are, in fact, cute people in Grand Rapids. It was news to them!

It's been fun here at the end of the year to ask students some details on how, exactly, the video was recorded. It's clearly a one-shot take that winds through the streets and walkways and bridges of downtown Grand Rapids. But how does the camera operator get around? More than two modes of transportation were involved.

One small puzzle I haven't researched to fruition is the version of "American Pie" used for the lip dub. It's not the famous studio version from the album of the same name. Nor is it the live version from McLean's Greatest Hits Live! album, recorded in 1980. So the lip dub version is unavailable on iTunes.

And as I tried to convince my friends at PhET, no on-going concern that hopes to promote its cause does so without a T-shirt. Or several. GrandRapidsLipDub is no different.

UPDATE: I found the "American Pie" source performance on YouTube.

Thursday, June 02, 2011

Nothing beats xkcd

Los Gatos physics teacher, Dan Burns, alerted the AP Physics EDG of another xkcd comic. It's brilliant (in the British sense of the word.) I for one frequently enjoy xkcd; Randall Munroe's humor really resonates with me.

XKCD Turn Signals

Wednesday, June 01, 2011

Seventy-five cents never went so far

I end the Physics 1 year with light and wave optics. Ray optics has been bumped to AP Physics 2. This helps to forestall the post-CST and post-AP doldrums that might otherwise take root. By the way, when students complain they can't do this or that because they suffer from Senioritis, I remind them that Senioritis is the disease, physics is the cure, and me? I'm the doctor!

Anyway, we get to rainbows, mirages, blue skies, 3-D movies and more during this season, so it's not so bad for anyone.

When we talk about diffraction, we end up doing an activity called "Diffraction in Action." (I know, too easy.) The activity ends with a pair of "rainbow glasses" being given to each student. Their experiences in the activity to this point allow them to see the glasses as crossed diffraction gratings.

But you'd think the Candyman had come to the room with delicious treats for the little boys and girls. Be prepared for squeals of delight and proclamations that this is the coolest thing ever and that they'll never take the glasses off.

To push the merriment over the top, I ask them to don the glasses and look toward my camera in the front of the room. When the flash pops, their collective shrieks are enough to provoke angry calls from the bowling alley, complaining about the noise we're making.

Worry not about any complaints from colleagues about the distraction that bespectacled students were in their classes. It's for science!

Of course, rainbow glasses don't grow on trees. You have to order them and pay for them. I get mine from Arbor Scientific for $0.75 each (volume pricing), so I can set up all my students for about $100. I've never been denied reimbursement from whichever funding source I've asked.

Blog of Phyz readers already know I'm a sucker for activities that get jaded high school seniors to act like elementary students--if even only for a little while. This active/giveaway meets that criterion with happiness to spare.

Diffraction in Action (PDF)
Diffraction in Action Answers (PDF)