modeling

Energy Theater

At the summer Modeling Instruction workshops in Columbus, we are often lucky to have prominent physics education researchers visit us and speak to our workshop participants. On Wednesday, Dr. Stamatis Vokos of Seattle Pacific University joined us and he completely owned the crowd. I might be a bit biased, as I was really jazzed about his presentation of the Energy Theater.

Using work done by the Energy Project, a research group focused on discovering best practices regarding the teaching of energy in science, Dr. Vokos shared with us a new way to think about energy transfers and transformations. Dubbed the Energy Theater, this representation allows the students to act out the energy transformations and transfers in a system with each student representing a single unit of energy. There is an article in the May 2014 issue of The Physics Teacher that gives a good overview and provides an in-depth look at how to use the Energy Theater in the classroom. I’m only going to share our experiences, so be sure to check out the article.

As it was shared with us, there are four rules to the Energy Theater.

  1. Each student represents a single unit of energy.
  2. Objects correspond to areas that have been marked off on the floor (likely by tape).
  3. Each student represents their form of energy with hand signs.
  4. As energy transfers and transforms among objects, students move to different areas of the floor and change their hand signs.

We were given the example of a cup resting on a hand. The cup is being raised at a constant speed. We chose the person, surrounding air and the cup to be the system. In a modeling classroom, we have tools like energy pie graphs or bar charts that would let us model the problem like this:

piecharts

The great thing about energy pie graphs and bar charts is that they let students show how the types of energy present in a system are transforming from moment to moment. However, they don’t really let students consider how the energy is transferring between parts of the system. For instance, where is that thermal energy? Is it in the cup? The person?

Using the Energy Theater, our group identified the objects in our system and marked off areas on the ground to represent them. We did our work outside, so we used the blocks of concrete and split them up as shown below.

Screen Shot 2014-06-12 at 7.16.41 PM

Next, we decided as a group on hand signs to represent each energy type. While you can use simple hand signals, I wanted signs that involved more of our body to make them obvious. We came up with the following:

  • Kinetic – a simple sideways-V formed by spreading the index and middle fingers
  • Gravitational Potential – both hands on our head
  • Thermal – fanning our faces
  • Chemical – both hands on our belly

This is where the physics comes in. We had to work out as a group how many units of energy were in each object AND in each form. Our location reveals where the energy is while our hand signal reveals what form the unit of energy has taken. We had to reason out how the units of energy should move within the system and how they should change as they did so. The result is a glorious ballet of physics teachers having way too much fun.

As you can see, we (as students) really needed to think through how the energy transformations of the very simple act of a cup being raised at constant velocity. How much thermal energy is in the body? How much transfers to the air? Do we ever run out of chemical energy?

As we concluded our work on that problem, Dr. Vokos asked us to try the case where the cup is being lowered. At first, this seems like a simple reversal of the previous Energy Theater. We quickly realized though that things were different.

See how much fun you can have at a Modeling Workshop?

Reasons I Like This

  • Energy transfers are explicit. Students sometimes have trouble connecting the states of a system. While the O of the LOL charts (a.k.a. energy bar charts) can show energy moving into or out of the system, it doesn’t allow students to show how energy moves within the system.
  • It’s another representation to add to the energy model. Modeling is about finding multiple, consistent ways to represent the same phenomenon and this leads to better learning.
  • This feels like the “Walking Out a Motion Graph” activity in which students model a position or velocity vs. time graph using their own bodies and a motion detector. I like those active representations.
  • It is scalable. If you don’t have room, students can draw the areas for objects on a whiteboard and move multi-sided blocks from area to area. Think of a six-sided die with the faces each representing a type of energy. Check out the Physics Teacher article for a good picture of this.
  • It fits well with pie graphs and bar charts. At any moment, the number of blocks of energy and their types can be determined, so the rest of the class could construct pie graphs and bar charts as students perform the Energy Theater. You could even create a stop-motion Energy Theater.
  • Thermal energy transformations become very apparent here. We quickly realized how much of the energy being used must be transforming into thermal energy.

Concerns

  • Energy as a substance. According to Dr. Vokos, this representation requires students to think of energy as “an immaterial substance”. This makes me uneasy. Will this confuse students? Energy isn’t a substance, but then again, forces aren’t arrows. And we already represent energy as blocks in energy bar graphs. Is it okay to use this model to help them understand energy transfers?
  • Tracking of info. With so many people moving and switching hand signs, it will be hard for students to track all changes at once while the Energy Theater is occurring. I think this can be alleviated by filming it for review or moving through it multiple times and stopping the performers at key moments to assess the current state of the system.
  • Disengaged students. Notice the guy in the green shirt in the videos (me). I picked a role that required me to do very little. In the first video, I chose to be a unit of kinetic energy in the cup which never changes. In the second case, I was a unit of chemical energy in the body that never transformed. In both cases, I was assigned my role and then could have chosen to ignore everyone else. Yes, this is more of a classroom management issue, but with so many students at once, I’ll need to keep an eye on it.
  • The gravitational field. Since using the modeling materials, I’ve taken to explaining that gravitational potential energy does not reside in the cup, but in the cup-Earth system. My students quickly take to this and it sets them up well for AP physics when we discuss conservative forces and fields. How to represent this cup-Earth system in the Energy Theater? Perhaps breaking one area into two smaller ones? Dr. Vokos was kind enough to speak with me at length about this. His suggestion was to place the energy in the cup initially. Use that as your first model. Next, change the mass of the cup. Make it more and more massive and look at how the Energy Theater changes. What would happen if the cup were as big as the Earth? In other words, use the Energy Theater to build towards a revision to your model of gravitational potential energy that requires this new cup-Earth thing to be included. Ultimately, you could even move towards including the field.

There are numerous extensions to this activity. A teacher could easily assign new and different situations for students to investigate or slightly alter the existing state of the system. You might make stop motion videos of the Energy Theater alongside energy bar graphs. This new representation for energy transformations and transfers had me really excited, but I want to think this through before I bring it into my classroom. If you have thoughts of your own about this, I’d love to hear them.

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Model Building on Spring Break

My school started its two-week Spring Break this past Monday. My honors physics classes have finished up the mechanical modeling materials (with the exception of the central force model). When we return from break, they will begin an investigation of light and optics. I didn’t want them to spend the next two weeks ignoring physics nor did I want them reading chapters from a book. To keep them engaged and thinking about the world around them, I gave them the following assignment. This is a great group of students this year, so I think our first day back will be very interesting.

We have spent months together not only learning about the natural world, but also learning how to learn about it. In our time together, we have developed models explaining the behavior of pendulums, objects moving with constant or changing velocity, projectiles, balanced and unbalanced forces and the conservation of two quantities (momentum & energy). The tools we have used include diagrams, graphs, mathematical equations and verbal descriptions. At this point, I want to give you a chance to strike out on your own.

When we return from Spring Break, we will be spending our time investigating the nature of light. What is it? How does it move? How does sight work? This study will include things like shadows, mirrors and lenses. We’ll look at the difference between colored light and the white light we receive from the Sun. In preparation for this study, I want you to spend some time during Spring Break doing one thing:

Develop a model for light or a light-related phenomenon.

What is a “light-related phenomenon”? Consider the following questions:

  • If shadows are blocking the Sun, why isn’t a shadow black? Why is it a diffuse gray?
  • Why is my reflection in a spoon upside-down on one side and right side up on the other?
  • Why is the sky red at sunrise and sunset, but blue during the day?
  • If you look at a green shirt under a red light, is it still green? What does this say about the nature of color?
  • Why does the portion of a drinking straw submerged in water seem larger or even broken from the portion still in air?
  • Can you ever add light from two sources together to produce darkness? Or do they always produce a brighter light?

During Spring Break, take time to look around you. Light is ubiquitous, yet to this point we may only understand its nature in a rudimentary sense. Make observations. Draw diagrams. Take pictures or video. If you choose to make measurements, record them. Write down your thoughts. Don’t daydream about light. Purposefully direct your attention to an observation about it. What do you notice? Alter the situation and see how things change. This will be challenging, but you are capable of doing challenging things.

When you return from break, we’ll spend some time together sharing what we found.  

Modelpalooza 2014

Here in Ohio, we have a very robust and active community of modeling teachers. Each year, under the careful direction of Drs. Kathy Harper and Ted Clark, we offer three different workshops (physics, chemistry and advanced) in Columbus as well as three follow-up weekend events throughout the rest of the year. The final follow-up of the school year is Modelpalooza, a day that brings together recent workshop graduates with experienced modelers from around the state. Often, experts in the field, such as David Hestenes, will come and present a talk, and in the afternoon, the advanced workshop graduates present the modeling units that they worked together to develop.

This year’s Modelpalooza was yesterday, March 1st. It remains one of those amazing professional development opportunities where I continue to learn and be exposed to new ideas despite having used modeling instruction for the past six years. We begin the day by sharing modeling success stories. This is important for the recent workshop graduates, as it not only gives them a chance to hear from experienced modelers, but also to share and acknowledge the transformations that they’ve seen in their classrooms over the past six months.

Rather than a national speaker for this year’s Modelpalooza, we decided to take advantage of the wealth of experience right here in Ohio. Experienced modelers presented break-out sessions in the morning to share their own work. We had sessions on CASTLE Electricity by Holly McTernan, Adjusting Modeling for Different Student Abilities by Joe Griffith and ??? (Apologies mystery presenter) and Standards Based Grading and Modeling by myself. I had really wanted to see Holly’s CASTLE session, as I have no direct experience with the CASTLE materials, but my own session went pretty well. The crowd had heard of SBG, but were all relatively new to it. Primarily, the presentation was a walk-through of my own adoption of SBG and what the transition was like in my modeling-based physics classes. A few folks asked for my presentation, so I’m putting a link to it below.

Standards Based Grading & Modeling Presentation – Modelpalooza 2014

The highlight of the day for me though was Dr. Harper’s presentation during the second breakout session. While Dr. Clark was presenting on PhET Simulations in the Chemistry Classroom, Dr. Harper shared a review of the literature on Expert-Novice Comparison in Problem Solving and Alternate Problem Types. I had tweeted some of the research based conclusions that most surprised me. For those folks that were asking follow up questions, I’ve included the literature review handout below. The conclusions that stood out to me were the following:

  1. Transferring math skills into physics is more difficult than transferring them into any other area. This is the Bassok & Holyoak paper below. Does this seem counter intuitive to anyone else? I would have assumed that physics (arguably the most mathematical of the sciences) would allow for a natural flow of knowledge/skill from one domain to the other. I haven’t had time to get a hold of the paper yet, but I plan to.
  2. Students plug numbers into physics problems to free up memory slots. Cognitive research shows that most people have about seven working memory slots in which to hold a piece of information for short term retrieval. Now take a look at one of the introductory kinematics equations – \vec{x}= \vec{x}_{0}+\vec{v}_{0}\Delta t+\frac{1}{2}\vec{a}\Delta t^2. If we consider only every variable a different piece of information, there are five symbols to interpret and keep track of. Your less mathematically adept students will have even more as they work to recall delta means “change in”, etc. By substituting numerical values into the equation early, students are able to lighten their cognitive load so that they can use it for other tasks. Dr. Harper suggests that we don’t push students to solve algebraically too early in their physics courses. Show them the power of it, keep revisiting it, and work them towards this skill once they have a stronger conceptual understanding. If I recall, this is the Sweller paper.
  3. If a problem takes a high school student more than 12 minutes to solve, they think it is impossible. I believe this is the Larkin paper. We’ve all had this experience with our students, but having a hard and fast number that I can tell my students to watch out for will make it easier for me to help them develop good problem solving habits.

The afternoon sessions consisted of the advanced workshop participants presenting on their work from the previous summer. This year we had groups working on circuits for physical science, a really cool equilibrium model for chemistry, and a rates of change model using wine glasses. I am always impressed by the level of thought and work that the presenters have put into their units. We always recommend modelers take that second year workshop, as it helps you move beyond the initial modeling curriculum provided in the first year.

With Modelpalooza 2014 behind us, we move into prepping for the next round of summer workshops. You can find out more about the workshops over at the AMTA website.

The Tao of Modeling

Today was our first full day of the workshop and things are off to a great start. First, we have a great group of teachers (24 in all) enrolled in the first year physics workshop. Even with the torrential downpour that we started the day with, each of them showed up eager and ready to begin. I’ve mentioned this in earlier posts about the workshops, but spending three weeks with a group of people who want to learn how to get better at their job is invigorating. It energizes you. And this time is even better, because I get to help them learn how to do that. Teaching teachers turns out to be really cool.

After paper work, introductions and FCIs, we got down to business and walked the participants through the ball bounce lab as a way to introduce model building. They did a good job as students – sometimes too good of a job – and kept the discussion moving along. They were a bit overwhelmed and had questions about all the things that everyone new to modeling has questions about: time, classroom management, textbooks, etc. My co-leader and I ended the day with some extra time in teacher mode to address their questions. As we fielded each one, I began to realize that I was responding with the same question I use on my students…”I don’t know. What do you think?”.

See, modeling is not a set curriculum, like say a textbook might be. It’s a framework or skeleton that can be used to build any scientific curriculum. How each teacher constructs that curricula differs according to their personality and classroom needs. There are a number of ways to guide students in the development and deployment of new models. For instance, I don’t use the ball bounce lab in my class while my co-leader does. He grades deployment labs while I’ve moved away from that. Whiteboarding might involve every group’s board going up for discussion or we might put all the boards up at once to look at patterns. There are as many ways to implement modeling instruction as there are teachers that practice it.

That’s one of the big lessons that I hope the participants take away from the workshop. Success as a modeler means finding your individual way…your path…your Tao. It means knowing your students and what the technique and tone for asking them questions is, because I know you have to question them, but I can’t know your kids. It means finding what is important to your class as the time crunch starts to force you to drop topics, because every modeler has had to (since meaningful reflection takes time), but we don’t know what standardized testing you face or what your principal will challenge you on. And it means deciding how to give your kids feedback, because I know you have to, but I don’t know how tightly you, your kids or their parents cling to grades. All I can do is share my way and hope it provides some insight to the teachers that will be trying this for the first time.*

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* – Contrast this with the highly scripted, one-size-fits all explicit direct instruction (EDI) methodology that seems to be the newest form of pseudoteaching.

…But Modeling Instruction Works Better

In my last post, I suggested that one of the ways to approach the subject of curricular and pedagogical change with colleagues, especially as it pertains to modeling instruction, is to share one’s own personal story of transformation. So here’s mine.

I used to be an awesome teacher. Seriously, that’s what everyone used to tell me and I had started to believe them. For the first six years of my career, I did my very best to make my classes dynamic and engaging by incorporating various types of activities. During lecture, I was enthusiastic and worked hard to distill an idea down to its essence when explaining it. My reviews from students were always glowing and the administration loved what I was doing. And the awards! In those six years, I taught at a rural public school, was a TA at a state university and spent the final year of the first six at my current school. In that time, I won three teaching awards and was nominated for two others. By every measure I had available, I was a great teacher. And then, the FCI came along.

The FCI (or Force Concept Inventory) is 30-question, conceptual multiple choice test meant to determine how well the students in your class understand the Newtonian concept of forces and the results of their application. No calculations are involved. The FCI came to me through Dr. Kathy Harper at OSU. She had presented a short, one-day workshop on modeling instruction locally and had followed up with flyers inviting the participants to the summer workshop. I signed up and as part of the process, I was asked to give my students the FCI before coming to the workshop. Looking over the test, I thought my students would make short work of it. After all, we were ending the year on magnetic induction, so surely they understood Newton’s laws of motion. We’d been using them all year. With the first year at my new school ending, I administered the FCI to my students. When I reached the summer workshop, I eagerly sought out the results.

College Prep Physics – Mean = 6/30 (20%)

Honors Physics – Mean = 9/30 (30%)

AP Physics C:Mechanics – Mean = 13/30 (43%)

WTF?! How were those scores possible? I spent a year teaching those students physics. The FCI covers some of the most fundamental ideas I told them about. They got As and Bs! The AP scores were all 4s and 5s! While I didn’t expect perfect scores, I did expect results significantly better than guessing. Those FCI scores were like a swift, spiritual kick to the head that altered my reality forever. I had to figure out what was going on. I began by doing what every normal person would do in this case – I blamed the test.

When I started the workshop, my skepticism for modeling instruction was high – very high. Of course, kids taught with modeling do better on the FCI – it’s written by the people that developed modeling! How does it relate to other measures of physics learning? (It correlates very strongly.) How many students do we have data on? (At this point, n> 10,000.) Students still learn by lecture. Why bother changing? (Because more of your students will learn more material using modeling.) All of my questions had answers. The research on modeling instruction and the tools used to evaluate it is extensive. (Here’s a start.) As a science teacher, if I’m going to talk the talk, I need to walk the walk. Having been confronted with what I found to be convincing evidence, I was obligated to investigate this pedagogy and see if it had an effect on how well my students understood physics. After the workshop, I returned home, prepared for the coming year and did my best to implement modeling in the following months.

It was difficult. I felt like a first year teacher again. Rushing home to review and prepare for the coming day, I was forced to truly change the way students engaged with the material and forego much of what I had developed over the past six years. Too many times, I’d start to revert to simply explaining some idea rather than forcing the students to provide the explanation. As the year progressed, it became even more difficult as we started covering content that the workshop never got to. I’d never been good at writing assessments and my old ones weren’t addressing the things I was now asking about. It was a mess. But there was a noticeable shift in how my students were acting in class. They began to enjoy the content rather than the show I used to put on. Their confidence in their knowledge was much greater than it had been in the past. But, to my critical eye, those things, while very important, were not measures of how much physics they’d learned. Was this admittedly chaotic year more productive than the way things had been in the past? For that comparison, I needed the FCI.

At the end of that first year of modeling, I only gave it to my honors physics class. I hadn’t taught college prep that year and hadn’t used modeling in AP. Nervously, I scored the tests and tabulated the results:

Honors Physics – Mean = 18/30 (60%)

I stared at that result for a long time. Even in the face of the frankly terrible job I felt I had done that year, my students had shown incredible learning gains. The next two years showed even greater improvements on the FCI as I refined and adapted modeling instruction to my own style of teaching. The pre- and post- scores remained consistent with the national averages. Additionally, enrollment in the 2nd year AP Physics class has grown from 4 to 13. AP scores remained high. And the unmeasureable qualities I mentioned earlier continued to grow in both intensity and frequency. From those results, I had to conclude that modeling instruction was more effective than lectures at producing lasting learning and getting students to adopt a Newtonian view of the universe. That seems like the only logical conclusion to draw. It would be irresponsible of me to continue to teach the way I had been when confronted with this information. So, I started using modeling and have not gone back. That’s my story.

I’ll leave you with this analogy. Newton’s law of universal gravitation works. We used it to discover Neptune and Pluto, both invisible to the naked eye. It predicts the paths of comets and dates of eclipses. We could continue to use it, but then we’d miss out on solving the mystery of Mercury’s perihelion, the bending of starlight, GPS, black holes, the origin of the universe and more. If you know about general relativity, but refuse to use it, then all of those problems remain unsolved. I refuse to leave any tool unused that will demonstrably improve the knowledge and experience of my students.

Lecture Works…

Recently, the Twitterverse has been awash with debate on the merits of traditional lecture-based instruction in science classrooms. I’ve watched with growing concern as many of my progressive colleagues have made claims that “Lecture doesn’t work.” or that “Kids don’t learn from lecture”. These blanket statements are both demonstrably false and harmful to the dialogue and discourse about research-based practices that many of us support.

Let me be clear about this: lecture can be used to teach students. That’s not my opinion. That’s a research-based conclusion that can be drawn from this graph:

from How Effective is Modeling Instruction?

If you have trouble reading the graph, the vertical axis is the mean FCI scores for students in physics classes and the horizontal axis is the type of  instruction students received. See that first bar? Students in a traditional (i.e. lecture-based) class, showed a gain of 16 points from pre- to post-test. That looks like learning to me.

Now, you might be saying, “But what about the modeling bars? Even novice modelers achieve greater learning gains with their students than lecture-based classrooms.” And you’re right. However, when comparing those bars to the traditional one, all I can conclude is that modeling instruction is more effective than traditional instruction. Those results don’t invalidate the gains showed by the students in the traditional classrooms, nor do they invalidate the methods used in those classrooms. Teachers who use lecture have students that learn. (I won’t even go into the anecdotal evidence. Suffice to say, that I only received traditional instruction and I think I know a thing or two about physics.)

I love modeling instruction and I wish that every physics and chemistry teacher out there would undergo the training, adopt it and use it in their classrooms. Like many of my colleagues, part of the reason I join the conversations on Twitter and write here is to spread the word about this amazing research-based pedagogy. When I see teachers curious about it or challenging it, I like to talk to them and find out what they’re thinking. But, if I lead with a statement like “No one has ever learned by lecture.”, they’re going to think I’m foolish and give much less consideration to the rest of what I have to say. It shuts down the discussion before it can even begin.

Getting teachers to take a look at modeling and seriously consider it requires them to challenge their preconceptions about the way education works. Mine came with my first post-test FCI scores. Malcolm Wells, one of the fathers of modeling had a similar story. I think most of us come to appreciate and understand modeling instruction through redesigning the model of education that we have built in our heads and that we have implemented in our classrooms – not by being told that what we were doing was wrong. Ironically, lecturing people about it just isn’t that effective. Instead, if you find yourself with the opportunity to share your passion for this method of teaching offer the evidence that supports modeling or even better tell your own story about how you decided to change your viewpoint. Give your colleagues the chance to discover what you’ve known for a while now. I promise that if you let them do that, you’ll be more effective.

I Love Lab Practicums and So Should You

I love lab practicums. If you don’t use modeling instruction, the name may have a different meaning for you. In modeling, a lab practicum is a deployment activity in which students are asked to use the model they have developed to accomplish a specific task. Ideally, the arbiter of success in the task is Mother Nature. They might be graded, might not be, but they always provide students feedback on their understanding of the model being studied.

The classic example in modeling is the constant velocity buggy crash (aka the two-train problem) Having already determined the velocity of their own buggy while developing the constant velocity model, each group is paired with a second. They are challenged to use the constant velocity model to determine where the two buggies will collide if they are started at opposite ends of a horizontal ramp. They cannot run both carts together until they have made their prediction and are ready to test it. The excitement and enthusiasm students show for these activities is infectious and the assessment of their knowledge is raw and honest. They can’t hide from it. Either the cars collide where they predicted or they don’t.

As part of the #physicsmtg that I took part in, we brainstormed and shared alternate practicums that we could use for many of the modeling units. Here is a list of some of the ideas tossed around: Lab Practicum Ideas. This is only a quick list and some of the names may seem strange. If you’re curious about any of them that I don’t cover below, just leave a comment. We also looked at Practicums for Physics Teachers by Henry Ryan and John E. Barber.

Friday afternoon, we decided to setup and test two different practicums and a demo that many of us hadn’t seen. Here are some quick descriptions that should allow you to utilize these in your own classroom.

1. Two Ramp Race (for Constant Force Model)

Kelly O’Shea shared a practicum with us that she had originally learned about from Matt Greenwolfe.

Start with one ramp already set up at a 10° angle and the other at 5º. Tell the students that you will start the cart on the 10º ramp one meter from the bottom. They have to determine where to start the cart on the 5º ramp, so that the two cars reach the bottom at the same time. You might let them run each cart separately or require them to just use their models to make predictions, but the test of their knowledge comes at the moment they place both carts on the ramps and let them go.

I like this one for two reasons. First, it’s a natural continuation from the constant velocity (crashing buggies) and the constant acceleration (race down the ramp) practicums. Second, it’s clear cut and requires students to demonstrate understanding of the core principles of the constant force and constant acceleration models.

2. Simultaneous Collision (for Conservation of Momentum Model)

Mark Hammond set this one up, but I neglected to snap pics. In this practicum, two low-friction plunger carts are placed on a dynamics track centered between two bumpers. To minimize the mathematical difficulty and emphasize the physics concepts, choose a total distance between bumpers such that the total distance covered by the carts is a round number (e.g. 50 cm). That is the total distance between bumpers would be 50 cm plus the total length of both carts end to end. Deploy the plungers and the carts will strike the bumpers at the same time creating clearly audible simultaneous sounds.

At this point, provide masses that are equal to the mass of the cart, so that the students can double, triple, etc. the mass of either cart. Give them time to experiment with the setup and discover the pattern rather than directing this part of the process. Once they feel that they have determined a predictive pattern, test them one final time by making one of the carts have a mass of 1.5m. If they can’t accomplish this, send them back to the drawing board rather than moving them on to the final stage.

The challenge arises when you next provide the students with a rock and ask them to use the setup to determine its mass. They may use a balance to measure the mass of the carts, but not the mass of the rock. By drawing on the predictive model they have built, along with their knowledge of conservation of momentum, they should be able to determine the unknown mass.

I find momentum-related practicums to be difficult to make exciting without expensive ballistic pendula or car crashes. This one is easily affordable and challenges students to reverse the application of a model in the same way as the Matching the Beat pendulum practicum does. The scaffolding in it is well done and customizable to the class that you are teaching. If students need the practice, do each of the instances above. If your class is full of super-stars, drop all or nearly all of it. I think that I’d like more practicums that I do to have this scaffolding feature.

3. The Tin Foil Capacitor (for Electrostatics model)

Frank Noschese led us through his awesome tin foil capacitor demo and we discussed how to develop this into a practicum. Check out Frank’s post (linked above) for a video demo of the setup. This is a great demo that can be used to look at the distribution of charges on the surface of a conductor. Electrostatics is very light on practicums and I think that there is one lurking in here somewhere, particularly if you roll it up with an insulator sandwiched between the layers of the roll (thanks for the idea, Frank!). This could get at capacitance and how it depends on area. I need to think on this one more over the summer and try it myself.

When it comes to assessing with practicums, the teachers in the room had a wide variety of practices. For instance, Kelly and Mark use the Two Ramp Race as a test in their class. The setup is in one room and when the students are ready to try, they can enter and test their predictions. On the other side of the fence, I tend not to grade practicums and only provide verbal feedback about their process both during and after the activity. Of course, since adopting standards based grading, I’m thinking that these practicums would make ideal moments to score students on the relevant standards. It would provide one more data point for them to measure their progress.

So, modelers, what are your favorite lab practicums?

Edit: Due to my non-existent Latin skills.