## Tuesday, February 28, 2012

### Review!

The physics classes made some review boards for the midterm exam, splitting into groups, with each pair or trio working on one standard.  Some are great, some are good; all should be helpful in the review process, so here they are, physics-nauts!

FFT
Beats
Oscillations: Period and frequency
Interference and Reflection
Standing Waves
Timbre
Causes of Oscillation
Amplitude
Wave Descriptions
Resonance
2 Source Interference (they ran out of time on this one)

## Wednesday, February 15, 2012

### This is a good day

OK, it's nearing the end of the term.  For you SBG superstars out there, it probably means that you're busy with reassessing kids like I am.  Here's one story that made it worth it today:

A student was reassessing on gravitation.  It's a difficult, abstract, and unfamiliar topic, so I'm glad that they get a chance to work on it and take another crack.  She was down to the end, but couldn't get a part of a problem dealing with the surface gravity on some other planet - she had determined the freefall acceleration, but couldn't remember the kinematics toolkit (she knew that it applied, though, which is great).  She confirmed that the kinematics part was separate from the gravitation part, and I thought she'd hand in the towel then.

Instead, she worked some more, and then came back and said... "I just solved it with graphs instead."

That's the best thing that I ever heard.

## Tuesday, February 7, 2012

### Winter Meeting: Tuesday Afternoon

I saw Kip Thorne's plenary session on black holes and gravitational waves - very interesting.  I didn't blog it because I needed all of my faculties to follow his tensor analogies. :)  The sensitivity of LIGO detectors (around 10^-16 cm) is about 10,000 times smaller than the width of a nucleus - that distance change over the distance of 4 km beam paths!

There's a post earlier about my talk, which was just after lunch.

Following that, I went into "Effective Practices in the Instructional Laboratory"

Slipping Spheres and Sliding Blocks: The "Role" of Kinetic Friction
• This session is mostly about the race of a sphere and block down a ramp
• It begins with a multivariate analysis of the parameters of the problems and how they affect the outcome of the race (low angles: ball, high angles: block)
• They go through the experimental setup for determining the motion data and friction coefficients
• There are some interesting (though small) changes to the friction coefficient - the sphere's decreased and the block's increased as the acceleration (in a half-Atwood system) increased
• They're the same material (wood), but the shapes might be an issue
• Nothing really here about using this in education, but it's a possible place for the AP class to investigate
Teaching Optics in the Introductory Mechanics Laboratory
• Labs tied to the course could become demos that don't engage the students and have them focus on too many components (apparatus, design, analysis, etc.)
• Instead, these folks keep the concepts pretty much the same during the term for the lab work, and don't progress with the material (kinematics and forces in first term, DC circuits in the second - which is in lieu of class instruction!)
• Intertwining of lab and class exposure causes analysis issue on how effective each component is
• They're using optics in the 1st term to free up time for other stuff in the 2nd term, and they never teach it in class then
• Optics labs: wrote and reviewed lab papers, did point and extended objects, refraction, beakers, lenses, not really any mirrors, modeling images
• Removed the mechanics labs during lab session, did some quick mechanics lab investigations in class instead (focusing on error analysis, etc.)
• Optics Concept Assessment pre-/post-test
• Students did as well on optics as students with more "rigorous" in-class experience
• FCI/FMCE gains were somewhat lower than in previous years, but he doesn't think that it was necessarily caused by the labs' removal
• Giving it 8 months later, students had basically forgotten their optics knowledge, but they have no previous tests to compare to
• Contact: masters@ipfw.edu
Assessing Student Learning of Error Propagation in the Undergraduate Lab
• HW from Taylor's An Introduction of Error Analysis
• TA didn't lecture during lab, so HW was never discussed as a whole
• Think-Pair-Share was used a bit
• There was a gain: 5/25 to 9/25 for one question, 5/25 to 15/25 for the other (significant gain)
• They classified the wrong responses: direct/fractional issues, typos, multiplying uncertainties, assuming dependence (adding uncertainty)
• The 2nd time, everyone at least tried it
• The pre-test was after a first semester though, so... yikes.  It's only a bit less scary after the 2nd term
• Contact: barker@nscl.msu.edu
I stayed for a couple of other talks here, but got tired of typing. :)

It has been a great Winter Meeting - thanks to all of the great speakers and the organizers!  After grabbing a bite, I'll head to the airport and back to the land of no palm trees.

### The Physics of Osmos: AAPT Winter Meeting Presentation

Here's the video presentation from the AAPT Winter Meeting.  Sorry, but there's no audio here - this is the video that played as I gave the talk, but it speaks for itself in some ways.  I'd love to add more, but my schedule says that it probably won't happen!

The image should link to a public file in my SugarSync account - please let me know if you can't access it!

### Winter Meeting: Tuesday Morning

Just one session in the 8 am block, then to breakfast and practicing my presentation!

It's a good one, though, a 30 minute session in the "Using the Riches of Astronomy to Teach Physics":

Using Black Holes and Extrasolar Planets to Teach Kepler's Laws (and more!)
• They're certainly popular topics, and can help kids get into several basic physics topics
• Kepler Mission: looking for transits around other stars using super-precise photometry
• Neat - data shows six different planets around a single star
• There's a Lego Orrery that they're using to simulate it (kepler.nasa.gov/education) approx. \$100 cost
• Vernier light sensor, lamp, planets, calipers (one broken bulb from clamping calipers :) ), light baffles also needed with multiple setups
• They have TA introduce the idea - going from the data and getting students to figure out why the light dips seems a better tack
• Questions that they have them explore: How does the % of light blocked depend on size of planet (prop. reasoning and scaling argument), orbital distance effect (you'll be getting into apparent/angular size here, which doesn't matter in the normal scale, but matters here)
• Neat light curve from three-planet system
• Orrery seems to not give correct orbital periods (qualitatively OK, though)
• They have one group design for another group (and predict the resulting light curve), and the other group has to figure it out only from the data; I like that bit
• At that point, they start getting tricky: moons, rings, off-axis transits
• Kids like it - duh! :)  It looks fun, for sure.
• Next activity: about the supermassive black hole at the center of the Milky Way
• Uses data from the UCLA data on Saggitarius A
• That's a sweet animation - I want it!
• Students get ta plot of the paths, without context - students figure out that they're orbiting something, figuring out that it has lots of mass -> black hole
• I guess that I'd tell kids that they're stars, then let them reason down that they're orbiting something much more massive (since that object doesn't seem to move), and get to BH that way
• The plot is angular, so they need the distance to the galactic center (8kPc) - that might be tricky for my kids
• We don't know the constant for ellipses in our honors class, so calculating mass would be difficult
• The orbits are inclined, so there's that - this is getting complex quickly
• Some student report: "We didn't think that astronomers actually had to use equations in real astronomy" - interesting: why do we teach them?  To punish the students, I guess...
• This is recent science, and the same science that "real scientists" are working on now, rather than long-settled questions
• Neat: you can sometimes see the little bump from reflected light as a planet's about to go behind the star - apparently, the loss of that reflection's called a secondary eclipse

## Monday, February 6, 2012

### Winter Meeting: Monday Night

Here's an interesting one - an hour on the AP Physics B Course and Exam redesign (about time!):
• Well, of course the NRC accused AP Physics B of being a mile wide and an inch deep - it's the poster child for it!
• That seems to have been a trigger for similar redesigns of other AP courses
• Interesting, but not really surprising, bar graph of the results of surveys of colleges about coverage of topics in different semesters
• Good seven big ideas of physics: don't have time to get them down, but... Systems have properties, interactions are forces, waves mediate p and E exchange, math is useful for describing nature, didn't get the rest
• Tradeoff: reduced credit for students scoring well on the B exam if it's split, but increased access (especially given that they always recommended B being a second year course)
• I might like this...
• It might not align well with some state graduation requirements (like California)
• They're promising a detailed curriculum framework, including boundaries and depth
• Adding inquiry and conceptual reasoning
• Proposed release date: Fall 2014
• Nice question: "I was at one of these meetings two years ago, and I saw a similar talk, that said that it would be coming out in two years."
• They're saying that having B1 (mechanics) as a first course would prepare students to do well with both parts of AP C in a second year.  The idea of having an option for the B1 kids to take a second year (particularly those without the calculus prereq.) of physics is good, though I don't have a free prep to teach it!
• Now we're talking about the curriculum
• They're saying that the curriculum isn't a sequence or a pacing guide, but instead a framing of the seven big ideas
• Each big idea has some 'enduring understandings' subordinate to it
• Below that, there's 'essential knowledge' (more than just facts, allegedly) and 'science practices: inquiry and reasoning'
• Below that, nougat
• A second shot at Big Ideas: "Objects and systems have properties such as mass and charge.  Systems may have internal structure," "Fields existing in space can be used to explain interactions," "that force/interaction one", "missed one", ""Changes that occur as a reult of interactions are constrained by conservation laws," "Waves can transfer E and p from one location to another without the permanent transfer of mass and serve as a math. model for the desc. of other phenomena," "The math. of probability can be used to describe the behavior of complex systems and to interpret the..."  Sorry - I type too slowly
• The division here lends itself pretty well to SBG
• The "science practices" are being shared among different AP science courses - that'll help out our benchmarking!
• Some examples: models/representations, math, questioning, plan and implement data collection, three or four more; they says that they're available on the AP site, since they're common to all courses
• Each of those comes with several skills used to demonstrate the desired practice
• Essential knowledge and science practices are alleged to collide inelastically and usefully to the teacher to become learning objectives
• They've promised that there are no required labs about 6 times
• An unfortunate example of one of the Essential Knowledge items: "A force exerted on an object is always due to the interaction of that object with another object."  Will there be a list of underlying assumptions, since there's a big one behind that statement?
• Rotation being added (angular kinematics and momentum, torque without angular acceleration)
• For some reason... intro circuits is in the AP 1 course.
• It's starting to look a bit more packed now: kinematics, dynamics, p, E, oscillations, waves and sound, rotation, statics, electric circuits
• C courses left untouched (at this point)
• Symbolic problem-solving, lab and analytical skills, experimental design, more reasoning questions, deeper conceptual questions, error analysis, much more writing to justify understanding: changes to the exam
• Overall, it seems like a good pitch.  We'll see how it plays out (can you tell that I'm skeptical of the College Board? :)
• Afterwards, a good story when talking to the presenter about the (grossly disfunctional) AP audit process: one of the teachers that wrote one of the sample syllabi on the site (which I basically had to copy to get them to accept my audit proposal) had her syllabus rejected. :)

### Winter Meeting: Monday Afternoon - Popular Media and Online Courses

After some In-N-Out Burger goodness, we're back to "How I Use Popular Media in Teaching Physics"

I've seen more people with tablet computers (not 'toy' tablets, but actual PCs) than I have since I taught at an all-tablet school!  I love my Lenovo tablet!

Angry Bird Physics

• Rhett Allain!
• This vehicle for engagement and analysis has been pretty well-covered (certainly very well by Rhett himself) in the blogs and even mainstream media, but I wanted to get it straight from the horse's mouth :)
• A little Tracker analysis - I love using the quadratic fit rather than even the v vs t slope - kids often think that you can get the v directly from the video, not even knowing that there's an error-inducing difference quotient in there
• The split blue birds have a total mass 45 times the mass of a single blue bird?!
• The yellow bird analysis (what happens when you tap?) is a decent entry-way into designing an experiment that will need revision (it's not immediately clear what's going on and how to analysis the data), but it would really take a long time to collect all of that data, and I can see that many students would be disillusioned by that
• The white bird egg dropping seems not only to use non-real physics (no problem), but it seems to reinforce some pernicious misconceptions (the egg always falls straight down, momentum's not conserved even in a conceptual way, etc.).  This may do more damage than it's worth, considering that students usually remember the first thing they see/hear, and that we've previously set up a few examples to illustrate that the physics is (sometimes, at least) good in this game
• Good point that this requires indirect techniques, which is very indicative of science - we can't just weigh the rock, but have to come up with a way to get at what we want by measuring what we're able to measure
• Contact:
Next, I slide over to the "Online Physics Courses: Technology, Assessment, and Experiences" session:

Transforming Physics Curriculum by Teaching Physics Online
• First point: online learning needs to be personal - tailored to the student, flexible, etc.
• Star Trek IV clip!
• Interesting: he's not afraid of making a statement.  So far, he's said that electronic books, regular books, and clickers are a dead end
• Biggest point is that changing the content isn't the answer - it's about how the content is taught
• The classroom needs to be a safe space where students can learn and discuss without the fear of punitive grading - sounds like SBG to me!
• His vision seems to be about social media more than anything else
• OK, here it is: the social homework project
• It's supposed to enable students to collaborate on their physics HW and to learn from each other.  There are peer-review, group solving, and discussion capabilities for rich-context problems, and they write problems and questions for other groups as well
• It looks like a Facebook app/group for collaboration, basically.  Everything seems to be in an early form yet
• A questioner brings up a common issue with discussion forums: frequently, a well-meaning student will "give away" the solution - this requires management and acculturation
• Contact: hlousek@csulb.edu
Particle Physics Online
• This is about a CSU-wide online course in particle physics (senior undergraduate level)
• They used Elluminate, with downloaded equation packet, live lecture with video camera with some whiteboard space.
• They scanned and sent in HW, he sent back scores only
• Tests were given live, by local faculty as proctors
• Could any research-inspired methods be incorporated here?  Is that less important as the audience is winnowed down to upper UG physics majors and grad students?
• Contact: pbsiegel@csupomona.edu
Online and Blended Climate Change Courses for Educators from AMNH
• This is about some courses developed in partnership with the American Museum of Natural History and NASA
• They aren't inquiry courses, but say that they try to model it
• They're using a stripped-down and more accessible version of the global climate model
• Good lessons here about bringing together model, theory, observation, causality, etc.
• rsteiner@amnh.org
Tabletop Kits Help Students Grasp Concepts in Light

• These kits are designed for students taking distance (or face-to-face) courses as a relatively simple way to get hands-on intuition about light
• There's color mixing, diffraction spectra (glasses), some LEDs to demo things
• Neat experiment using two LEDs to simulate amber light - very different spectra
• Spectra about CFL backlit monitors
• Apertures to develop the ray model of light - good conceptual question about a hole at the end of a hallway
• Pupil aperture size/power
• Point vs. extended sources through apertures, also with shadows
• Neat question giving two point sources, location of shadow components on screen - where's the shadow-caster?
• Ray tracing to determine image location with flat, curved (cylindrical) mirrors
• Photoelectric-type effect: UV making paper glow green, red light won't
• Peacock feather for iridescence
• Increases engagement, but doesn't always transfer - more mental-model creation needed in structure of investigations
• millspaj@ipfw.edu
We'll be back after dinner!

### Winter Meeting: Monday Morning - DIY Tech, PER, Physics in Animation

After a very welcoming "First Timers" breakfast, I made my way to the "DIY Technology for the Physics Classroom" session, where I saw three talks.

General observations (going into my thinking process about my talk tomorrow):
• There are kind of a lot of folks at each talk
• 10 minutes, especially compared to the usual 95 minutes that I get in class, is not a lot
• I hope that the contrast for the Osmos clips is good in these bright rooms
• It would be nice to include some expanded references to the Osmos talk for reference.  I'll see if I have time today to get that done!
IPAL: In-class Polling for All Learners
• Bill has developed some open-source polling software that can be used with any web-enabled device - no clickers required
• The Moodle or stand-alone modules can import ComPADRE or other established question sets, so you have something to start with at least!
• Bill Junkins is happy to help you out with this: junkinwf@eckerd.edu

Using Your Classroom Projector to Demonstrate Some Properties of Light:
• Wow: DLP projector technology seems to be overly complex, but very neat: strobe light + rotating color wheel + tons of tiny individually-aimable mirrors!
• The LCD projector's dichroic combiner cube looks like a good total internal reflection demo/application for class
• Using holographic diffraction grating glasses (cheap!), which are 500 line/mm diffraction gratings, looking at vertical lines through the projector is a neat demo n color mixing, and also showed that we didn't have an incandescent bulb in the projector
• Using a polarizer, you can show that the projector's green light is polarized perpendicularly to the red and blue!
Build your own electric field demonstrator
• This is supposed to be a simpler demo than the "grass seeds in mineral oil" demo
• This demo uses lettuce seeds instead (more arrow-like) and vegetable oil instead, with a VdG to set it up, along with a hangar, styrofoam cups (to stand-off the hanger between the vdG and petri dish.  Put paper under dish for camera mounted above, use fluorescent tube to bleed off charge
• It should spark between the wires, and the seeds will move quite a bit
• He showed videos of monopole source, dipole, parallel plates, absence of field inside a conductor (my favorite)
After this, I went to the "PER: Investigating Classroom Strategies" session:

Getting the Word Out: Effective Communication of PER Study Results
• This is about not original research, but best communicating the results to others; she's a science journalist as well, so uses lessons from that field
• The fundamental disconnect between being aware of data and an actual change in behavior is really analogous to the whole "book learning" issues for students and, apparently, for teachers taking PER results seriously - many teachers know about it, but still continue to lecture
• I want to DL this one to share.
• The information-laden approach that we try to use to advocate for research-based instruction is just as big a problem as trying to do it with students
• "The deficit model assumes that the public are empty vessels waited to be filled with science knowledge, upon which they will rationally act" (OK, I typed it quickly - maybe not a quote)
• Unfortunately, initial emotional appeals, etc. with some data as support are more effective than a data-driven approach
• Be upfront about the challenges of implementation - many try reformed strategies, only to drop them after a term or so
• Contact: stephanie@sciencegeekgirl.com
The Challenges of Assessing Teaching Effectiveness: Strategies for PER to Influence Practice
• Importance is for quality assurance (from the institutional side) and for personal teaching reflection and modification
• Aligning the assessment instruments for those purposes (and aligning them to PER) is important
• This alignment isn't usually present, though: lots of reliance on student evaluations and other poor measures by institutions. External measures, like the US News rankings, are super-terrible
• The heavy use of student evaluations makes folks nervous to change things for fear of lower evaluations (even if the measures of learning increase!)
• We need more and better-publicized research-based assessments
• PER is good as the lesson/course level: was the lesson/course successful?  It doesn't have as much for program-level assessments, but there's starting to be focus on this at a political level, so we need to catch up
• Measuring progression of reasoning skills and conceptual understanding of specific concepts across a program are easier; we don't have much for problem-solving skills yet - what would that look like?
• Contact: charles.henderson@wmich.edu
Variance and Variables: The Analysis of Pre-test Results from Thousands of Students
• It must be nice to have a gigantic data set (like several introductory courses in a large college)!
• We're comparing pre- and post-test data
• First question: are they normally distributed?  Normal quantile plot
• ...or binomially distributed? (as if they were draw from a population of students giving random correct/incorrect answers)  Nice presentation - there was probably the biggest binomial-gaussian distribution comparison graphical analysis audience laugh ever heard.
• Amount of prior instruction: ANOVA analysis showing differences between no instruction, some instruction, and all instruction; not much difference in many cases
• Open question: why are some questions binomially distributed and others not?
• Contact: pheron@uw.edu
Designing Research-based Instruction in a Large Lecture Course Without Recitations
• Intro calculus-based college course: 4 lectures, no recitations or TAs, lab not run by teacher
• HW assignments online, most tests multiple-choice
• In such a traditional, inflexible environment, how can we use PER?
• Prelectures/checkpoints (multimedia, animations, etc.): works better than text reading, students like them
• LON-CAPA and some turned-in work (mostly on form)
• You-tube videos of worked problems - takes that out of classroom
• <10 minutes of actual lecture
• 3-8 daily voting questions, using colored cards instead of clickers
• Important strategies: leaving the stage, answering questions, monitoring student discussions
• FMCE gains weren't super-duper, but the checkpoints and cards helped somewhat
• Some research cited on "high structure" classrooms, and how that helps at-risk students
• Nice distinction: urban, rural, and... frontier - he does teach in North Dakota.  Nice graphic on >50% of the counties in ND which have <= 6 people per square mile!
• Warren.Christensen@ndsu.edu
Learning Integration in Physics Using Debate Problems and Multimodal Communication
• Looking at center-of-mass determination
• Conceptual intro to continuous distributions: here's the discrete definition, which is the continuous definition? (poll question)
• After that's done, how do you determine if they really have it?  A couple of diagrammatic methods shown, ask them to derive the integral def'n from the discrete (hard), ask them to apply the integral equation (not the same as understanding what it means), have them use multiple representations (diagrams, etc.) - best!
• 1. Group discussion; 2. Groups present to each other; 3. Recorded presentations shared between sections
• They assessed individual student presentations with Smartpens, so you have to paper and the student's narration
• Another example question: I for rod; determine integral expression for rod around parallel axis
• Result - lots of students think that 'd' in an integral means 'change', and maybe this is the first static integral they've ever seen!
• vonkorff@phys.ksu.edu
The next place I went was to a talk given by Ron Henderson (physics PhD, Princeton, formerley worked at Cal Tech) on how waves are encoded in animation.  Ron's a DreamWorks animator.
• 22,000 Intel Xeon cores, 120 TB or storage, 120,000 frames, >1 billion files for a single DreamWorks movie - yikes.
• The animation rig for a single character in one of these movies can have up to 10,000 controls - lots of strings for a puppet to have
• 200-800,000 hairs for a rendered cat, like Puss in Boots.  ...then you have to make the hair go around the belt, etc.
• Goose feathers: 'grown' via algorithm along equipotential lines, in order to minimize collisions between them (just like real goose feathers, approximately). So there.
• Volumetric modeling of clouds for high-res 3D models, like in the Jack and the Beanstalk bit
• 34% Bachelor's, 40% Masters, 20% PhD among R and D engineering staff; degrees most common in CS, Engineering, graphics, match, physics (4%), in that order
• Premise: non-physical motion is distracting to audiences.  Why don't they hate Star Wars then? :)  It all really depends on knowing what your audience knows and doesn't know!
• A good way to plan out a complex endeavor: they look at each movie and ask themselves: "what do we want to go after that we haven't gone after before?"  You can't reinvent every wheel every time.  Pick your battles.
• Breakdown of man-hours for effects for Puss in Boot (in order): clouds, dust, destruction, water, splashes, tornado, beanstalk
• Their destruction model includes: explosive, primary debris (moment of inertia, spin simulation here!), secondary debris, dust source, fluid simulation, and visual development; fracture analysis, particle dynamics, rigid body dynamics, and fluid simulation are the primary models for destruction animation
• Their model selection is artist-driven, so multiple approaches/representations are very important for them
• There's a nice explicit balance between physical law (simulation) and computability (using simplified models).  This is a good thing to emphasize with students: we understand the approximations and simplifications that we use (and why!), but we can usually do a better job of getting students involved in that process!
• Incompressible Euler equations sued for tornado simulation; apparently a common model for fluids in animation.  They're controlling a buoyancy term, a dissipation term, and a third term.
• The complex behavior of the tornado comes from solving the equation for lots of little boxes - the coupling between the boxes creates the complexity.
• They let the artists control divergence terms to make it look how they want it.  They add obstacles to respond to the artist requests to "make it more turbulent"
• They warp the physical simulation onto a controlled skeleton to compromise between the desired physical and un-physical parts of the animations
• Great question from the crowd - "there's lots of physics going into making the animations look great - is there a lot of biology going into the beanstalk animation (and others)?" Answer: "no."  There are skeletons, etc. but skin and such are algorithmic at this point (designed to "look right", rather than physical simulations).
• This was pretty awesome.  The 45 minutes flew by - I could stand another couple of hours of this!
...off to In-N-Out Burger!

## Saturday, February 4, 2012

### California ho!

So... anyone going to the AAPT Winter Meeting?  I'm leaving early in the morning tomorrow, and I'll be able to catch some of Sunday, all of Monday, and most of Tuesday.  I'm looking forward to a bunch of new ideas and sharing with other physics teachers.

If you're there and you're looking for something to do, why not drop by EH01 at 1:15 on Tuesday to see my "Physics of Osmos" talk?  I'll look at how the video game can be used to supplement or replace some traditional demonstrations, can help build intuition about orbital mechanics, and can be the springboard for sooooo many independent modeling projects!

Here's to a smooth travel week, and to Wednesday, when I'll be getting into Philly at 6 am and going straight to school to teach (fun!).

See you there!