Electrical Engineering: A Project-Based Course

This year, with the new Electrical Engineering elective (prerequisite: electronics), I'm trying out a fully project-based course. With the background knowledge that they have and a whole lot that they pick up along the way, these students are going to build a robot to respond to this central prompt:

Robots overcome obstacles in many different ways; some are similar to the methods that humans would use and some are markedly different. The goal here is to design an "obstacle" and a robot to navigate the obstacle. Teams will build both the "arena" in which the robot operates and its goal location, and their robot must overcome the obstacle to reach the goal. "Obstacle" could mean many different things, definitely not limited to physical obstacles - a solar-powered robot may have darkness as an obstacle, a robot on Venus would have to overcome high temperatures, and a rescue robot would have to overcome uneven terrain.

Along the way, teams will need to meet several intermediate goals, producing several 'deliverables,' which demonstrate planning, incremental progress, and proof-of-concept for their robot.

Deliverables:

• "Obstacle" description, along with ideas (plural!) about how the robot might overcome it (team evaluation )
• Specifications sheet: details your robot's inputs (information from sensors), outputs (expected behaviors, actions, etc.), and expected exceptions (problems that can occur) (team)
• Three Arduino projects from the texts that could pertain to your problem (individual evaluation; three projects different from your partner's three). For each, summarize how you think it might pertain to your project and show how you modified the project/sketch to change how it functions in some way. Present these as a Youtube video, with commented code (showing especially the modifications) linked
• Program flow chart (detail the sequence of sensor readings, calculations, and outputs that will take place in the loop, as well as the preliminary variables that need to be set) (team)
• Contribution to the WCGW? (What Could Go Wrong?) meeting: brainstorming unexpected exceptions for other projects - if you help them figure out the potential issues, they'll be able to design around them. You'll get the same help (individual)
• Schematic: Arduino and all associated electronics (sensors, motors, LEDs, etc.) (team)
• Sensor and output validation: show, with isolated snippets of code, that you can accurately measure whatever sensors are measuring and accurately control any output devices (individual - one partner designs, executes, and videos illustration of inputs, the other does the outputs). Present these as Youtube videos
• Landscape, including the "obstacles" and a goal. The robot needs to be able to detect when it's in the goal! (team)
• The robot, fully functional (team)
• Reflection on the process and the big question of how robots overcome obstacles and how that is similar to or different from how humans do (individual)

Each of the deliverables will be evaluated on the 11-point scale. Teams/individuals must earn at least 7 on a deliverable in order to proceed, with revision increasing the grade. The final evaluation will take place together, with the five arenas and robots moving towards their goals simultaneously. This is their 'exhibition,' and I'm planning to invite as large a committee as I can to make it an authentic experience. 

Electronics: Goals and Ideas

This year, we've added a physics-based elective strand, consisting of Experimental Design, Electronics, and Electrical Engineering.  The electronics course is a prerequisite for the EE course, but you don't have to take both. The experimental design course is a bit of a singleton, which I'll get to in another post, but I'm a month or so into the electronics course, and wanted to share some of the paradigms of the course and see if anyone had any helpful ideas or experience teaching HS electronics to add.
Big Ideas

• The course is more of a phenomenological look at electronics than a physical ones. That is, we're dealing with it as electronics folks would, rather than as physicists would. We can't get into a lot of heavy Maxwell's equations action, and we're not getting into an extremely precise model of the physics of current flow (Matter and Interactions does a great job with this, but it's not within the goals of the course or the mathematical tools of the prerequisites), and no differential equations to deal with RC, RLC circuits, etc. I want students to have a practical understanding, supported by theory where necessary and possible.

• There's a big emphasis on assembly, schematics, soldering, etc. I want students to be able to read and use a breadboard, a schematic, clip leads, meters, and to be able to solder.

• I want to hit the most important devices and concepts - resistors, capacitors, various sensors, etc., and also classic combinations of components (which are applications of these), like voltage dividers, voltage regulators, rectifiers, etc. This is one spot where I'd love a lot of suggestions; my formal electronics training has principally been physical, rather than practical.

• The primary lens through which I'm going to have the students comparing different classes of devices is the i-V curve. Batteries, resistors, diodes and LEDs, and PV cells are the primary devices that I have on that list. Let me know if there's something that I'm missing. Capacitors will be in there, too, but they don't fit well into this paradigm.

• I'm using (supplemented by my own stuff) the Make:Electronics book. There's a great deal that I like about it and some things that I don't (particularly on the theoretical end), but it's a good place to start. Students also get the kit for the first set of experiments, too. That's pretty expensive, and I probably can buy the parts and distribute them to them next year for a much smaller cost to them.

The StandardsThese will likely wiggle a bit, but here's where I'm starting with the learning standards for the term. Seeing where we are now, I'm thinking that capacitors will wait until the next term (EE). Let me know if anything's missing, etc.! ...I'll likely split the power and energy stuff out as its own standard, either next year or before the end of this term.

Resistors

• Apply the loop and junction rules to battery/resistor circuits, both qualitatively and quantitatively
• Appropriately use Ohm’s law to describe one or more resistors
• Analyze series and parallel circuits
• Determine and apply equivalent resistance
• Recognize, apply, and analyze iV curves of resistors and batteries
• Determine the power expended by resistors and connect energy and time
• Use current as a measurement of rate of charge flow

Switching

• Identify and analyze open and short circuits
• Use and analyze SPST, SPDT, and DPDT switches
• Use and analyze relays
• Analyze circuits containing PNP and NPN transistors

Capacitors

• Understand relationship amongst voltage across a capacitor, charge stored in it, and its capacitance
• Qualitatively analyze steady-state capacitor circuits
• Apply the loop rule to circuits with capacitors
• Determine and apply equivalent capacitance
• Calculate energy stored in capacitors

PV Cells

• Recognize and analyze iV curves of photovoltaic cells
• Analyze PV cells in circuits

RC Circuits

• Qualitatively analyze (graphs of) voltage, current, and charge as time goes on
• Analyze the steady state of an RC circuit
• Use the loop and junction rules to determine current, voltage, charge at some moment in time
• Calculate and apply the time constant of simple RC circuits
• Advanced: use equivalent circuits to determine time constant

Diodes

• Differentiate between and apply ideal and realistic diode models
• Compare diodes with resistors and batteries
• Recognize and analyze a diode's iV curve
• Understanding and apply the concepts of threshold and breakdown breakdown voltage

Project

Schematics

• Recognize components on schematic:
• Batteries
• Switches
• Capacitors
• Resistors
• Potentiometers
• Diodes
• LEDs
• PV cells
• Junctions
• Draw schematic, given circuit (clip leads or breadboards)

Assembly

• Construct circuit with clip leads, given schematic
• Recognize components visually
• Breadboard circuit, given schematic
• Solder components, with or without perf board

Units

• Properly and consistently use units
• Fluently deal with metric prefixes
• Convert units fluently
• Check for proper unit cancelation

Algebra

• When appropriate, use symbolic algebra (no numbers until the end)
• Recognize unreasonable answers
• Reason proportionally
• Fluently solve equations

SBG and Exam Scores

There are a variety of ways to deal with big summative assessments (final exams, etc.) in SBG. Because the scores on standards are the result of several assessments on each standard, work, reassessment, etc., I generally don't want my final exams to upturn (for good or ill) a term's worth of work - one day does not a term make. I do like the summative nature in this context, though, and the huge opportunity for including lots of connections between standards. The question is then just how to include these assessments in the students' grades in a way that reflects all of these realities and tries to (as always) make the grade represent student understanding as closely as possible.

For a while now, I've been counting the total grade from the standards as 80% of the term grade and the exam as 20%. You could adjust the ratio in a variety of ways, trying to give the exam 'teeth' or to not over-weight a single snapshot on a single day, but that's not the interesting part.

Before I switched to standards-based grading, my students' exam scores were fairly consistently lower than their grades going into the exams (you could say the same thing about any bigger assessment during the term, too). This led me to have some 'insurance' in the grade - participation, HW, etc. One of the reasons that I switched to SBG was that I felt like these sorts of components in the grade, which do not reflect student understanding, were muddling the meaning of the grade and were inflating student scores in order to arrive at a typical grade distribution.

Since I've switched to SBG, my students' exam scores and their grades going into the exam have become more and more correlated.

This year, almost no students had more than a 6 point discrepancy between their averages and their exam scores, and the differences were evenly distributed between higher and lower. My grade distribution is the same as it was before, but those grades represent a higher level of understanding than they did before, and my grades more accurately represent my students' understanding.

As I handed exams back today, some students were clearly nervous, asking the usual questions: "how were they?", "were the exams good?", etc. I reflexively started with some sort of answer, but then I just said it: "they correlated very closely with your grades going into the exams. ...do you know why?" First student answer: "because that's our level of understanding!"

That's all that I've ever wanted for a grading scheme. Well, that and giving actionable feedback, communicating learning as a priority, and motivating a drive for improvement.

Standards for the Year

We had a great discussion on standards-based grading at the Global Physics Department tonight. Here are my standards for the year for each course, in response to a request from that conversation.

AP Physics:

• Term 1 (Momentum Principle)
• Term 2 (Energy Principle)
• Term 3 (Angular Momentum Principle)

Honors Physics:

• Term 1 (Motion, Forces)
• Term 2 (UCM, Gravitation, momentum)
• Term 3 (Energy, Oscillations, Static Electricity, DC Circuits)

Physics:

• Term 1 (Motion, Forces)
• Term 2 (Oscillations, Waves)
• Term 3 (Sound, Phases/Eclipses/Shadows, Geometric Optics)

LaTeX Code for Standards

If you're interested in displaying coarser standards with core skills and proficiency indicators (or whatever you want to call them) in nice LaTeX boxes, here's some code for you!

There are two main templates that I work with - one with a subtitle for the standard and one without. The centering on the vertical text doesn't (in my experience) work, so I just have to play with the size of the parbox to make that work, but everything else renders pretty easily.

Edit: Thanks to Aaron Titus for pointing out two necessary inclusions:
\usepackage{multirow}
\usepackage{graphicx}

No subtitle:

{\footnotesize \begin{tabular}{| p{.7 cm} | p{1.7 cm} | p{13 cm} | }
\hline
\multirow{8}{*}
 {\rotatebox[origin=c]{90}{\parbox{22 mm}{{\large{\bf Friction }}}}}  
&Core Skills & Identify situations in which friction forces are present and understand the microscopic model of friction forces\\ \cline{3-3}
& & Differentiate between static and kinetic friction \\ \cline{2-3}
& \multirow{2}{*}{\parbox{1.7cm}{Proficiency Indicators}} & Determine the direction of the friction force \\ \cline{3-3}
& & Use an appropriate expression for the magnitude of the friction force \\ \cline{3-3}
& & Understand the relationships among normal force, friction force and friction coefficients \\ \cline{3-3}
& & Solve problems using friction \\ \cline{2-3}
& \multirow{1}{*}{\parbox{1.7cm}{Adv. Ind.}} & Solve complex friction problems, including banked curves (not at design speed) \\ \cline{2-3}
\hline
\end{tabular} }
\vspace{2 mm}

Subtitle:

{\footnotesize \begin{tabular}{| p{.15 cm}  p{.15 cm} | p{1.7 cm} | p{13 cm} | }
\hline
\multirow{8}{*}
{\rotatebox[origin=c]{90}{\parbox{32 mm}{{\large{\bf UFPM }}}}}  
&\multirow{8}{*}
{\rotatebox[origin=c]{90}{{\parbox{50 mm}{\scriptsize \centering Unbalanced Force Particle Model}}}} &Core Skills & Recognize when the forces on an object or system are not balanced from observation, graphs, equations, or descriptions of the motion  \\ \cline{4-4}
& & & Identify the presence and directions of normal, tension, and weight forces  \\ \cline{4-4}
& & & Draw a force diagram (FBD) accurately showing directions and types of forces acting on an object or system  \\ \cline{4-4}
& & & Write net force equations describing an object or system; they should indicate that the forces are not balanced in the appropriate dimension(s)  \\ \cline{3-4}
& & \multirow{2}{*}{\parbox{1.7cm}{Proficiency Indicators}} & Draw FBD correctly indicating that forces are not balanced; recognize same \\ \cline{4-4}
& & & Choose and consistently apply workable direction(s) of positive \\ \cline{4-4}
& & & Correctly apply Newton's 3rd law \\ \cline{4-4}
& & & Choose appropriate axes for force analysis \\ \cline{4-4}
& & & Solve problems using net force equations and/or FBD \\ \cline{3-4} 
 \hline
\end{tabular} }
\vspace{2 mm}

SBG Resources

I'm posting some resources from the SBG panel from today. Thanks to everyone that came! Here are some of the resources that we discussed:

• My Prezi (logistics)
• Stephen Collins's Presentation
• SuperFly (Andy Rundquist)'s Presentation
• My mindset materials: it's really important to talk a lot (that is, a little at a time, but over a long time) about learning, metacognition, grading, etc. 
• Lots of SBG links

SBG: Philosophy and Logistics

Teaching is always the best way to learn. Yesterday, Andy (SuperFly) Rundquist and I gave a workshop on standards-based grading at the AAPT summer national meeting in Portland. While preparing the workshop, I did several things. Watching all of Portlandia was valuable, but preparing the agenda and having conversations in the workshop were terrific.

Many of these teachers were on the cusp of their first year of SBG implementation, and itching for advice. One of the things that folks are always interested in is the logistics - grading scaling, calculating overall grades, mechanisms for reassessment, etc. The more important part, though, is the philosophy, and everything else is just implementation. If you're not sure what your purposes for assessment are, how that relates to feedback and what the students do next, then the potential benefits will be lost. This is an interesting contrast to traditional grading - because everyone's familiar with traditional grading, you don't actually need to consider why you're doing it, what you want out of it, exactly what the expectations are for the students, etc. That doesn't mean that any particular teacher doesn't, but think about it - do you really need to have a consistent philosophy of assessment to conduct your class and assessments that way? You really don't!

There are as many implementations of SBG as there are teachers, but there are, as I see it, two non-negotiable tenets of SBG:

1. To the best of your understanding, student understanding and the grade should be interchangeable, equivalent, homeomorphic, or whatever you want to call it.
2. Understanding changes over time (therefore... so should grades, by application of #1)

A corollary of #1 is that the grades have to be related to the content, rather than the assignments. That's where the standards-based part comes in. How you accomplish these, by grainy or coarse standards, student-initiated or teacher-initiated reassessments, with binary or other rubrics, etc. is highly dependent on your students (age, preparation, numbers), your school (time, culture, schedule), and you (personality, experience, class rapport). As long as you keep #1 and #2 in mind, communicate them to the students often, and everyone's clear that the students and teacher are a team working towards understanding, the implementation details aren't the main thing.

Basically, that's how you survive your first year of SBG. With that under your belt, start worrying about reducing paperwork, streamlining reassessment sign-up and administration, making reporting better, and all of that.

One big discussion that we had involved the inclusion of time as a variable in the grading. This is the default in traditional grading - there's not much reward for learning material after the test, so two students that both learn all of the material and score the same on the final could, because of the speed at which they learned it, get vastly different overall grades. The philosophy of SBG definitely tries to remove time as a variable, and I think that the improvement of grades to reflect improved understanding and the lowering of grades to reflect eroded understanding puts a very clear message out that enduring understanding is all that I care about, not how fast you learn or whether you can cram.

There was a little bit of pushback on that, and a good discussion followed. One idea thrown out was about employers - don't they want to know which person can learn the skill in a day instead of three? Probably they do, but I don't think that the traditional system actually communicates that clearly. Before I get to that, I don't think that it's appropriate to make that sort of thing an issue for novices; we're talking about kids in their first or second class here, not grad students ready to go into the workforce as physicists. 

The more important thing for me is the collateral damage that an attempt to include speed of acquisition by way of not allowing grades to change over time. The argument seems like it's about differentiating between these two kids:

...but in reality, it ends up being these two kids:

Without the incentive structure, support, and learning from assessments (when they're not final, they're easier to really take as indicators for improvement, rather than scarlet "D"s to be ashamed of and thrown away), a good number of those students simply fall of the the back of the pack, having a shaky foundation that they can't build upon. What I'm saying is that, with SBG, the
blue line" kid from the second graph can become the "blue line" kid from the first graph!

I've seen some criticism from others than SBG can allow higher grades than traditional grading. When applied correctly, that's a feature, not a bug.

My grade distribution is about the same as it was before, but each grade represents a higher level of understanding than before. When there's a mechanism to improve, the bar can be higher!

Interestingly, we heard from some local teachers that the state of Oregon is implementing SBG across the board in the near future. That seemed to have driven some of the high attendance in our workshop. I did a little searching, but couldn't find the details on the plan, so corrections/additions/clarifications are welcome in the comments. I'm certainly all for SBG, but it's really dangerous to make big top-down changes to these things. There must be a lot of teacher education and buy-in to make it work, or it'll be another passed ed fad, which would be a tragedy. Philosophy first, logistics second.

OK, tonight a little sushi to talk over the panel discussion on SBG that Aaron Titus, Stephen Collins, SuperFly, and I are leading tomorrow (8-10 in Broadway I/II) and then a day checking out Eugenia Etkina's new text at noon (Pavilion West) and the Demo/Lab (Galleria II) and Modeling instruction (Ballroom II/III) sessions from 4-6.

AP Physics C: Mechanics Standards 2013-14

I've finished revising my standards for AP Physics C: Mechanics for next year. The standards that I used last year were a little too grainy, for the most part, for my liking. I prefer having each model as a standard, with the specific content and skills subordinate to that model as indicators. This means that reassessments don't suffer as much from the "cherry picking" of students choosing isolated and unrelated skills to reassess. Because each reassessment is on a whole model, even a student that only had an issue with elastic collisions would still have to reassess on all of the related skills - identifying when CopM applies, deal with other types of collisions, etc. and demonstrating sustained mastery. This also keeps the number of reassessments that I have to make lower, with only 8-12 standards per term.

The standards reflect a hybrid AP/Matter and Interactions approach (I'm using Knight's Physics for Scientists and Engineers for the first time this year, alongside M and I). I weave the two together, including the topics that the AP curriculum covers that M and I doesn't and the larger narrative and inclusion of programming and modern physics of M and I.

The overview:

• Fall Term (the momentum principle)
• Unit 1: motion (constant and non-constant a and forces), drag, oscillations (springs and others, but not pendula), intro to Python
• Unit 2: momentum principle, momentum (conservation and impulse), circular motion (uniform and non-uniform), non-inertial reference frames
• Unit 3: chaos, relativistic momentum, materials (ball and spring model of matter, speed of sound, Young's modulus)
• Winter Term (the energy principle)
• Unit 4: work, power, relating U and F, gravitational and electrical potential energy, universal gravitation and orbits, conservation of E
• Unit 5: quantized energy (spectra), relativistic energy, mass energy
• Unit 6: real and point-particle systems, moment of inertia, conservation of energy with rotation
• Spring Term (the angular momentum principle)
• Unit 7: angular momentum conservation, torque, static equilibrium
• Unit 8: unbalanced torques, angular motion
• Unit 9: statistical mechanics: micro/macrostates, entropy, temperature, specific heat, Boltzmann distributions

Here are PDFs for the standards:

• Fall
• Winter
• Spring

Automatic Email Responses for Google Form Submissions

Since I use a Google form for student reassessment requests (very helpful, BTW), I've often had students forget what standard they registered for or which day or had "but I submitted it!" issues.

This script should solve that. In the form edit window, go to Tools and Script Editor, and add a script to your form.

Here's my script (modify to suit your needs):

function onFormSubmit(e) { 
 // these are the columns in the form:   
  var timestamp = e.values[0];
  var yourName = e.values[1];
  var Section = e.values[2];
  var std = e.values[3];
  var ReDate = e.values[4];

  var toAddress = e.values[5];

  var subject = "Reassessment Confirmation - " + std + " " + ReDate;
  var emailBody = "You requested a reassessment on: " + timestamp +      " for " + std +      ". \n\nThe reassessment will take place on " + ReDate +      ".";

  MailApp.sendEmail(toAddress, "you@yourschool.edu", subject, emailBody);
}

The last thing that you need to give the script permission to send emails. Go To Resources/All Your Triggers -> Run OnFormSubmit Events From Spreadsheet -> OnFormSubmit.

There are optional arguments for the sendEmail method that let you send fancy HTML emails, but this will work OK for me.
Enjoy!

Advice to Future Physics Students

This year, I had my students (physics, honors physics, and AP physics) this year write some advice to future students, paying forward their experience: things to do, things not to do, encouragement, etc.

I was very pleased with the types of things that they advised, and I put together a sheet for next year's packets with some highlights. The file's linked here, but I thought that I'd also share the process for making these (with the rotating font sizes, types, and styles) yourself:

• You'll need Python (script below) and LaTeX
• Type the advice into a plain text document (UTF-8 encoding, so that the apostrophes don't get lost in the LaTeX), one nugget per line
• I had it print only lines with * at the end, so that I could save all of the advice, but only use some of it. You can certainly modify the code to fit your needs
• You'll need to make a few path and file mods (it's also calling Preview at the end to display, so if you're not on OSX you'll need to change that too)
• Run and enjoy - let me know if you found it useful!

The script (quick and dirty - surely can be improved. For example, most of the imports don't really need to be there, but I was modifying an old script, and they weren't hurting anyone):

How Much Information Is Too Much?

We're getting near the end of the term, and there's a characteristic increase in the rate of reassessments. Some of this is just natural: there are more standards in play, and the standards introduced later in the term all must be reassessed in a shorter window than the earlier terms. Also, those standards are assessed fewer times by me, so some students that might've worked it out on another in-class assessment need to do it individually. Of course, there are also students putting things off until later in the term. Some of that, though, is also benign - there are a lot of papers/tests/projects/reports/HW due (with a capital 'D') in other classes, so, if they can still demonstrate that proficiency, but later in the term, that's just a good time-management decision. There will always be some students that procrastinate, too.

Here's a question that I've fielded a good number of times over the past three years that I've been using SBG: "will this standard be on a future assessment this term?" I've never quite known what to think about that. Several possible scenarios come to mind, some troubling and others perfectly reasonable:

• The scariest interpretation: "Can I just ignore this now?"
• "Should I bother to reassess this individually, or will it happen anyway without me scheduling and taking an individual reassessment?"
• Another cynical one: "At what point should I actually try to learn this?" 
• "I'd like to plan my limited number of reassessment days (remember that we're within a couple of weeks of the end of the term, and they can only reassess one std/day, only on M, W, F) - do I need to use those for a different standard, and pick this one up on one of yours?"

Much like Star Trek movies, two and four are good and one and three aren't. I might be overly optimistic, but I think that, for most of the kids that have asked me (thinking of the individual kids that have asked me), it really isn't a diabolical or cynical question, but one about time management.

I'd like to hear your thoughts: how much information should students have about upcoming assessments? I sometimes list the standards that will be the primary focus (no promises about anything else that might come along with those) on the calendar. Is that beneficial for time-strapped students trying to best plan how to demonstrate as many proficiencies as possible or does it support mercenary rating-collectors (points-collectors for a new age)?

Homework Worth Doing

I posted a few weeks ago about motivating kids to do homework by making it worth doing. That's a pretty heavy gauntlet to throw down, and I did have at least one Twitter response calling me on that. I don't claim to always have the right answer to this, but there are a few things that can take us in the direction of kid-obvious worth, I think:

• The most obvious kind is practice. This is an easy type of HW to give, but the tricky part is making kids see that they need it. Assessments should be framed as an opportunity for the students to find out what they need to work on - as formative, rather than summative, and HW is then the second step in a lot of cases. This is a difficult thing to do, and it requires a lot of frank talking with students in class, particularly at the beginning. I get better at selling this every year, but you'll never have every kid on board. Those kids that you can't ever get probably weren't getting much out of "completing" mandatory HW anyway.
• Deeper applications of concepts that you already know can work, but they can be difficult to pull off. Because of their nature, lots of kids are going to miss a subtle concept in there, and you'll have a few successful solutions waiting around for everyone to catch up in class. Depending on the kids and the culture, you may have a large percentage shut down and come in with something blank. It takes good scaffolding for these, and I'd use them sparingly - this is exactly the sort of thing that class is good for.
• Simulations or calculations can take some of the time-consuming, but not super-difficult bits of lab work outside of class. If kids are following up on a collision lab by calculating the center of mass velocity or change in kinetic energy for each system, that's something pretty easy for them to do, and they won't mind doing it (because it's not mentally taxing), but it'll save you class time. If they're at the point where they're pretty comfortable modeling, you can give them a simulation and have them model the relationship. I do this with universal gravitation (since we can't do the experiment in class anyway) and sometimes with circular motion, depending on how I'm feeling about experimental setup. At this point in the year (early second trimester), they're mostly ready to do that - certainly the design, data-taking, and graphical modeling, and most can do the algebraic modeling as well. We can then wrap up the relationship together and have a good discussion when they're 'fresh,' rather than after they've spent an hour taking data and running fits, etc.
• Another useful kind is new explorations. If they're framed well and have a low barrier to entry, they can be really productive. The first one where some kids obviously didn't do it should bring some helpful peer pressure as well. If you have one where nearly everybody doesn't do it and there's a frustrating day, that's a good candid conversation to have with them (and to remind them of the next time).

In this last vein, I have an example, using this gravity simulator (I just got sidetracked for 10 minutes playing with it while finding the link):

This is basically a way to get the conversation started on elliptical orbits, while reviewing a bit about circular orbits and Newton's laws. The kids come in with all sorts of observations and ideas, and it is a great springboard into the topic. If you do this in class, you end up having to curtail their investigation in the hopes of getting the discussion started, which isn't super fun for anybody. 

Not every assignment worth doing looks like this, but it's a way to start to think about meaningful HW outside of class that isn't practice on old topics. 

Yellow to Green

My grading scheme this year for AP Physics (C: Mechanics) has, so far, worked out the best that I've had for that course. My physics/honors physics scheme involves (basically) one or two standards per model, so the standards are fairly coarse. The problems are easy (enough) to generate, and reassessment at more frequent intervals is good for reinforcement, practice, and experience for those first-time learners. Applying that to the AP course in the past has been problematic, given the headaches of senior scheduling and senior motivation. It's also another group of reassessments for me to prepare, schedule, and grade. I posted about this before, but I've made a few tweaks and it's started to actually get used.

Here's my scheme this year:

• The standards are more grainy (see the list here), compared to honors physics (here)
• There are (generally) two assessments per unit in class
• There's one reassessment available per unit, covering the whole unit
• I made a chart showing the acceptable evidence for each standard. Typically, it'll be two strong showings in assessments/reassessments for that standard or one strong showing and several out-of-class successes (problems) or a capstone or several out-of-class successes and a capstone
• Everyone's required to do at least one capstone per term, even if you rocked all of your assessments
• Students submit this slip when they have some evidence to show for a standard.  There may be some revision needed before it's accepted.

The extra outside effort needed to find and do problems and/or capstones motivates them to do good work on assessments, without me needing to wade through another sea of reassessments.  The capstones are my favorite part, and they're coming up with some great ones (more on those as they mature).  Overall, I'm liking the balance between giving them flexibility with their busy senior lives, keeping them accountable, and respecting the fact that, even though there aren't so many grades 'in the book' right now, they're still working.

Today's a big day, because the first student went from yellow (NY: "not yet") to green (P: "Proficient").  Many more to come of those, as well.

This Year's Marshmallow Challenge

I always start off the year by doing (never by talking about the syllabus!).  We start with the Marshmallow Challenge, where the students try to build the tallest structure made of 20 sticks of spaghetti, one meter of tape, and one meter of string, to support a marshmallow as high off the ground as possible.

The TED talk accompanying it is great, and it's a great intro to standards-based grading.  What happened to those creative kindergarteners that were unafraid to fail and benefitted from their own mistakes to turn them into disaffected failure-shy business school grads? Well, school, mostly. The combination of high stakes (grades that are indelible) and low skills (what learner doesn't have low skills at the beginning?) creates all kinds of damaging behavior in the long-term (poor retention, little conceptual understanding, focus on "the answer," cheating, cramming) in the service of short-term gains, because those short-term gains are incentivized and they don't yet have the tools to earn them legitimately.

Anyway, this year I had 6 of 16 teams end with intact structures. The two tallest, both at 60 cm are below.

Last year's post

PS: I do allow them to use guy wires, but only connected to the table. Is that cheating? I dunno, but that's what I do.

Assessment Strategy for AP C

I'm running my AP C: Mechanics course a bit differently this year. Most notably, I'm using Matter and Interactions as the curriculum, which takes some major head-wrapping. I've done as much of that as I can before actually seeing students in the course. Frank Noschese, Mark Hammond, and I came up with standards and aligned old AP problems to chapters in M and I this summer, but the grainier nature of those standards presented me an assessment scheme challenge. Usually, my standards are much bigger, translating to fewer per term, and I only allow one standard to be reassessed per day (and only on M, W, and F, after registering via Google doc). Those standards, for fall and winter, look like this.

The AP standards look like this, with chapters 1-5 in the fall term, 6-10 in the winter, 11 in the spring (with some mechanism for including previous term standards that I haven't devised yet).

I was toying with some more project/portfolio-based assessment for this course, especially after I saw success with limited screencast reassessment at the end of last year).

What I'm going with is a combination of in-class and out-of-class assessment, which I'll put under the umbrella of 'portfolios.' Basically, there are a lot of ways that you can prove to me that you have nailed a standard (and it's your responsibility to make that case to me for each standard):

• Show me how well you did on in-class assessments that covered that standard and/or reassessments (I'm only preparing one or maybe two per unit)
• Show me how you applied this understanding to an in-depth analysis ('capstones')
• Show me a lot of problem-solving from the text (M and I's problems are generally pretty robust and most are not the kind of sterilized problem that you see in Giancoli, Walker, etc.)
• Ideally: all three.

I need a mechanism to make sure that not everybody's just doing problems, with all of the potential issues (ethics and others) that that entails. Maybe I'll make a tally sheet for them, so that they have to color-code the methods that they used, so they (and I) can see at a glance how they met the standard. I'd like to make sure that they do at least three capstones per term, as well.

I'm thinking about a binary scale (Yes, Not Yet) and a 50 + 50*(% of standards met) algorithm.

Thoguht?

Standards for (most of) the year

Apart from being deep in accreditation report-writing, I'm, like everyone else, deep in class prep. In case anyone's interested, here are my standards for the first two terms for Physics and Honors Physics and the whole year for AP Physics/Mechanics.

The links are to PDFs of the standards; there's a brief synopsis of the course content for each course so that you know what you're getting.

Physics (my own text - motion, then oscillations (not much force analysis), waves, sound, shadows, astro, optics)
Honors Physics (Mechanics for these terms, pretty modelly, using Giancoli as the text (read: problem bank), but probably Knight next year)
AP Physics (First half of Matter and Interactions)

...and another thing...

I tweeted recently about Sal Khan's (of Khan Academy) response in the Chronicle of Higher Education to the MTT2K tweet-project-happening-movement-thing, where teachers present critiques/parodies of Khan's video, a la Mystery Science Theater 3000:

I don't have a subscription to that journal, so I admittedly only commented on the excerpt on dy/dan.

Something in there's still bothering me, though:

     With procedural, worked problems: That’s how I learned, that’s how everyone I knew learned.

In addition to Dan's (and others') already-written critiques on procedural learning and lecture's general ineffectiveness (a point which Khan still seems not to acknowledge or even fully appreciate, which is the scary part, especially for someone being given the keys to the educational kingdom by many), there's another issue here.

One of the reasons that physics reform efforts (which are some of the most highly advanced, in terms of purposeful development and research support) have veered sharply away from lecture is that it's been shown to be ineffective.  One of the reasons that it has been a difficult sell to many (teachers, administrators, parents, students) is that lecture and procedural approaches were how they learned.

For most students (and parents and administrators as past students, unless they went into scientific/mathematical fields - but maybe not even then, if they didn't go into physics), it doesn't even work for them! It's familiar, though, and there's almost an idea that you're not supposed to understand physics and math.  It's a hoop that you jump through that you forget right after. We teachers see that mentality all the time, and SBG's a good way to start to stem that tide, but that's not my point here.

For physics teachers, it's a difficult sell precisely because lecture probably did work for them. I took a course similar to AP Physics B in high school (we didn't have AP-designated courses at my school, but it was basically the same course content) as my intro course, and a calculus-based course that was about the same as the two AP C course for my second course (and I had the good fortune to be able to take electronics and modern physics courses too).  After that first course full of a crazy amount of content, I really did have a solid grasp of the concepts beneath pretty much all of that physics.

That's a story that's been around forever - this worked for me, so it'll work for you. If it doesn't, then you're not working hard enough or you're not smart enough or whatever.  One of the historical failures of lecture was the inability to really reach folks other than those folks that become teachers, engineers, etc.  Everyone else was left out.

So if that's an old story, what's left to say? I think that one of the reasons that it could work for me was that I had time to engage with the material, even just inside my own head. I had downtime and time alone.  Quite a bit, really. There were no cell phones, text messages, Facebook, Twitter, etc.  I had email and FTP and Gopher, etc., but those weren't 24-7 sources of instant gratification like students have today.  I built stupid stuff, did silly projects, took apart things that I couldn't put back together, etc.  I wasn't out doing a Westinghouse project, I was just engaging with the world and, with some space and time, I was able to connect the real world to all of those things that I learned about in physics class.  I was interested in all of that stuff before I took physics, so I had a leg up (especially on the many kids that I see that don't know how to use a wrench or don't understand what are and aren't good uses for duct tape, etc.), but the space to do that experimentation before, during, and after my physics education was important, even if it didn't look like it all the time.

Regardless of the reform method, the key is stimulating this engagement.  Whether it's SBG, modeling, peer instruction, etc., that's really always the lynch pin. In the past, there was opportunity for that thought and experimenting (building things, etc.) outside of class, even if the lecture itself wasn't convincing to everyone that that was something that they should do (and even if it didn't really train them to do that well or at all).

Today, kids don't have (mostly through choices that they make, though there's great societal pressure to make those choices) the long stretches of attention to devote to turning these ideas over in their minds.  There's always a text message to reply to or some other distraction.  They're just never alone and their time is increasingly sucked into reactive communication.  Never before have so many been able to talk so easily and had so little to say.

If they're sitting in class listening, almost all of them are not really engaging with that material.  Outside of class, almost all are trying to get through whatever assignment or test prep they're doing so that they can get on to the next thing or the next text message, interrupted all the while so that most can't even do that bit efficiently.

What reform education methods do is actually carve out time for that reflection to happen. 

The key is to walk into the class and see what the kids are doing.  If it's something, it's probably a lot more effective than doing nothing while sitting and listening. 

Yes, it'd be great to for kids to be able to do more of this outside class, but the deck's stacked against us.  Even when kids did have time, the success rate of lecture was abysmally low. If we teach them how to think and reflect and analyze, then we know that they're actually doing some of that (because we're there when it happens), and we may even stimulate them to do more of it while they're not with us. Win, win, win.

Framing the Semester, Finding the Model

I had to fudge a bit on my assessment scheme several times this year.  For each model, I identified "core skills," "proficiency indicators," and "advanced indicators."  For example:

 It seemed like a no-brainer to me that identifying when the model applied was a non-negotiable line in the sand - you are "not proficient" (the lowest of five/six levels) if you can't do that.

Reality intervened a bit - there's definitely a spot along the learning continuum where students could apply conservation of momentum fairly well, but the process of determining why momentum's conserved for this collision but not that one, etc. can actually be quite difficult, so I didn't always enforce that as an automatic NP frequently, though it certainly didn't tell me that you were proficient.

My first (and probably second) response was to move that skill up a level, so that you can be "developing" without being able to determine every case for which the model applies, but not "proficient."

While that's probably still what I'll do - it represents a different perspective on the mental development of the models than I had last year - I think there's a bigger opportunity here.

Part of the problem with developing those skills is the nature of developing one model, then the next, then the next, etc.: for the first half of the term, there's not much suspense as to which model will apply, so students don't necessarily get an authentic experience of discerning which model applies.  Even if you put in some time having them discern whether the one or two models that they know apply, there's not much suspense most of the time, because they generally know that they'll be able to solve almost all of the problems that you give them.

Here's where my idea comes in: I'm going to use a recitation problems system similar to Kelly O'Shea's, but we're not just going to look at them a few weeks before the end of the term.  We're going to start them on day one (ish).  We'll look at a big list of situations, most of which we have no idea how to attack.  We'll identify why the model(s) that we know so far don't describe these, or try to apply them and try to recognize their failure.  We'll really learn to identify when our model(s) will work. We'll motivate the construction of new models - "hey, we still can't doing anything with those colliding cars, because we don't know the force acting between them, and it's not going to be constant anyway.  We need something that can deal with that - let's crash some carts and see if we can model them!"  I think that this could be my game-changer for my students' big picture understanding of models and their ability to solve the really sticky ill-posed problems (you know, like life).  At the end of the term, we can look back and have a really tangible reminder of how far we've come.  Seems like I have three sets of recitation problems to write.

Reassessment Management

Lots of folks (including me) have posted about reassessment management for SBG: it's a real logistical issue, and it can really reduce the amount of time that you get to spend on thinking about how you run class or your time to help kids or (usually) personal time.

I have three and a half things to say about the process:

1. Start using ActiveGrade/BlueHarvest
I haven't actually used BH, but it has many of the features of ActiveGrade, for which we were a pilot school this year, plus some others.  The key here is that it makes the process of storing feedback and creating a record of the change in understanding for a standard workable.  Before this, all of the feedback was lost, stuck on that paper that maybe was thrown away.  I had a system before for keeping track of the progression of scores (crazy Excel macro action), but it didn't get the feedback.  I hear that there may be some document uploading added to ActiveGrade before next year, too!

Where I had this last year (yeah, inches of paperwork), in addition to the Excel sheets themselves and the process of PDFing and posting individual grade summaries...

... I had only ActiveGrade this year, with the added functionality of all of that feedback.  Big win there.  They also started doing an automatic alert to parents and advisors when scores were entered.  There's a report that you can cook up yourself, but it takes some time, and the incremental notification might be nice, particularly when there's an alternate system for grade reporting that every other teacher uses (like we have here) - it avoids the two login hassle a bit and means that there aren't surprises at the end of the term, though I fear that it might trigger the helicopter parent assaults early in the year.

2. Use GoogleDocs to Schedule Reassessments
I started using a Google Form this year to have students sign up for reassessments (which I also restricted to only M, W, F, in order to give me some prep time/breathing room).
It looked like this:

This really helped the process, gave me an easily sortable list in order to prepare the reassessments efficiently, and was well-received by the students.  I can't believe that I went through a whole year last year having kids wander in, show me some problems or whatever, and me making up reassessment problems on the fly for each one.  That was nuts.  Now they're ready to go, sitting in each student's personal folder in the reassessment box on reassessment day!


2.5. Make the Standards Coarser... if you want to
I had fairly 'grainy' standards last year: constant acceleration motion was like 5 standards, maybe.  This year, I made (basically) each model a standard, so I had something like (for honors - regular is a completely different set of models): CVPM (split into graphical and algebraic the first term), CAPM (split the first term, CVPM and CAPM combined into 'Motion' in subsequent terms), BFPM, UFPM, Friction (these combined as 'Forces' in subsequent terms), UCM, GM (gravity), CoEM, ETM (work), CopM, pTM (impulse), SEM (static elec.), CEM (current electricity), Algebra, Units, Modeling, Writing, Error Analysis (the last three are tricky, and maybe the topic of a later post).  Anyway, this reduces the number of reassessments by reducing the number of standards, makes their preparations more rigorous (because there's more material on them), and forces connections among different parts of each model without being (for my taste) too muddled.  One key is how you communicate the scores, though.  I used a scale of NP (not proficient), De-, De (developing), P-, P (proficient), A (advanced - again, a sticky issue to deal with), and gave feedback with a series of tables on the last page of each assessment (or reassessment).  That looks something like this:

This keeps the feedback obviously specific for the students, without making me keep track of 50 standards per term.  I also type most of what's written into the ActiveGrade report when I enter a score.

I also started letting students make a screencast if they had a P- because of only a single issue/with my permission ('nice job conserving momentum, but you need to work on using the speed of approach/retreat to  analyze those elastic collisions'), which seemed to give good results in terms of what they produced and how much they reported that it helped them solidify their understanding.  I felt that they needed to be at a relatively high general level of understanding with the standard already to keep these 'honest,' and to make sure (for my sake and theirs) that the ability was there to transfer a description of what's happening ('energy's being transferred from Ug to K) into effective problem-solving.

I get the arguments for grainy standards, and I've done that myself, too, but I think that I'm sticking with this for all of these reasons.


3. I'm going a step further
Even with the Google form, there's still some hassle, and I devote a couple of hours per week to just printing, copying, filing, etc. reassessments, not to mention creating them.  I started developing a couple of Python applications to help me with this.  I'm posting code on github (I'm new to that, so I think that was the proper link!), if you're interested. [Share, attribute, and give me a shout if you use it] Of course, I'm no star programmer, and these are my first two Python programs, so suggestions are welcome.


The two programs do this (so far):

• reassess.py: it opens the saved sheet (CSV) from the Google reasssessment form and creates headers with the reassesser's name, the date, the standard, and the section.  There's a spot for the questions to be imported, but I'm still working on the DB (next program).  Most exciting, it creates a LaTeX document (using a common header) and PDF for each student with all of that, including a graph paper watermark (Thanks, Mark Hammond!).  Once the questions and standard tables (see 2.5 above) are in there, it'll make its own reassessments and send them to the printer (hopefully with the double-siding, stapling, and punching!).  One button, one day's worth of reassessments.  This took me about three days. Here's a sample output PDF (so far):  

 

• problemdb.py: it creates the problem database from a set of LaTeX documents (sans headers), each with a unique numerical filename, a second line which is a comment containing a list of standards covered in the problem, and a third line which is a comment containing a brief description.  It searches the problem database for any combination of standards that you enter and returns a list with the problem numbers, descriptions, and standard sets (and images, eventually) for matching problems.  This will let me populate a column in the Google spreadsheet assigning problems for each kid's reassessment, which reassess.py will add to their LaTeX documents.  I'll also make it print out a PDF of search results (with solutions), so that I'll be able to make keys easily.  This one took me about two hours (so far).  That's a nice learning curve!  Here's a sample of a single standard search and a two standard search, with only three problems in the DB so far:

 

Why We Run Towards the Gunfire

We had some scheduling issues last week in physics with visitors, so I made an in-class assessment a take-home assessment.  One great thing about SBG is that there's really no point to cheating on such an assessment, so I think that I'm still getting a good picture of where they are.

On this question, they were (in general) in the weeds:

" Two radio towers 30 km apart transmit synchronized 240 kHz signals.  If a car equipped with a radio receiver tuned to the transmission frequency drives directly from one tower to the other, what will the receiver hear?  Explain; a diagram would help!  Radio signals are light waves that travel 300,000,000 meters per second.

What would the signal be like at a point along the drive that is 8750 meters from the first tower

How would the driving experience change if the radios’ frequencies were changed to 300 kHz?"

We've done some work with 2-source interference, from looking at the "overlapping ripples" diagrams to doing some predictions of frequency from two interfering sound waves given the locations of some points of constructive and destructive interference in the room.

This is the same concept, but a different-looking context, and that's where kids that haven't quite figured out the whole axiomatic reasoning thing have difficulty - yes it looks different, but we can still use the same principles to make predictions about what happens.

In particular, the big message for 2-source interference is that, even though both waves start in phase, they may not be in phase when they reach you, if you're different distances from the two sources.  The difference in travel distance determines the phases of the waves and whether they'll interfere constructively or destructively.  [This type of relationship is familiar: rates (relatives of differences) are famously difficult for students to intuitively grasp - see calculus!]

Back to the story, though:

I collected the assessments at the beginning of class and then posted this problem via projector.  I set the online stopwatch to five minutes and told them to come up with something coherent in their whiteboarding groups. There was a good discussion after that, and we made a lot of good connections.

...before that, though, there was an audible groan when I posted the problem.

Why?  It's a hard problem!  They've already wrestled with it for some period of time, felt anxiety that they were adrift about (da-dum!) an assessment problem, and here I was bringing it up again.

Here's the thing, though: you don't learn anything by running away from those difficult problems - you have to figure them out so that you can use that understanding in the future.  Denial is death in problem-solving.

Soldiers and police officers are incredible because they run towards gunfire, while the rest of us run away.  There's an anxiety-filled and dangerous situation, but they do the harder thing and confront it directly.

In physics (or learning in general), we have to run towards the gunfire too - you have to seek out and fix those misconceptions and misunderstandings.  It's anxiety-filled, too, but one student yesterday noticed a crucial difference between the two situations, when SBG is used: for us, the wounds aren't permanent.  

Not Proficient? No problem - wrestle with the problem, come back, and then you'll be whole again.  Using traditional grading that students are accustomed to, I totally understand why they get gunshy, even at the level of course selection.  Reminding them that this is a safer space for making mistakes has to be a constant occurrence because of that ingrained anxiety, but it's well worth the effort.