Month: March 2014

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.