Archive | September 2011

Day 17: Buggy Challenge

Today we did the buggy challenge. Each group was given a buggy and 8
minutes to determine the speed of their buggy. As groups finished, I
took away their buggy and paired them with another group and asked
them to predict where their buggies would have a head-on collision if
initially separated by 3 meters.

I’ve seen/done multiple variations of this challenge over the years.
Instead of a head-on collision, you can simulate a tortoise-hare
scenario and have kids predict where the fast buggy will pass the slow
buggy. You can make the tortoise-hare more challenging by telling
students something like “5 seconds after the tortoise passes the hare,
the hare wakes up and starts running” rather than giving kids a
separation distance. Metronomes (web-based or otherwise) work well

You could even start the buggies at a right angle to each other to
simulate collision at an intersection. Kids would have to determine
when and/or where to start the buggies.

My biggest problem is making sure everyone is engaged for most of the
time. What do you do?


Day 16: VPython on a USB Stick

The video shows a VPython program which simulates a fan cart that has an initial velocity to the right, but the fan is blowing in the opposite direction, causing it to slow down and speed back up to the left.

We’ve been having issues getting VPython installed and running properly on our school network. With the help of Perica Zivkovic at, I’ve made a version that will run off a USB stick (or a your network drive, where ever). Just unzip the Portable VPython 5.7 folder and put it the unzipped folder on the USB stick (or where ever).

To run IDLE:

  • Inside the Portable Python folder, go into the App folder.
  • Drag the file icon “” on top of the file icon “Pythonw.exe”

I’m sure there must be a script I could write to automate that process, but I don’t know how.

This is great because now students can use VPython on most any computer. (Though I don’t think this will work with Macs.)

Day 15: Color-Coded Graphs and Diagrams


Taking a page from Knight's textbook and Matter & Interactions, I have begun to require my students to color code their diagrams. Blue is for position and displacement (area under velocity graph). Green is for velocity. Black is for objects (dots) and graph axes. Red will be for forces and for acceleration (using double-headed arrows). While I don't have any official research to support this, I think the use of color will decrease students' cognitive load when interpreting and looking at diagrams on each others boards and on worksheets.

I stuck with using red for acceleration (Knight uses orange) because of the standard four color whiteboard makers and the 4-in-1 colored pens my students should have with them each day. I use the double arrow head for acceleration to distinguish it from force and to aid red-green color blind students when reading motion maps with green velocity arrows.

Stay tuned for more examples!

Day 14: Position, Distance, and Displacement

As a check for understanding, I asked students to draw 2 position-time graphs: one in which the object's position, distance, and displacement were the same value at the end of the motion, and another in which those values were all different. Then I asked students to look for similarities among the "same values" graphs and among the "different values" graph.


Day 13: Unity Day


It’s Homecoming Week and today is Unity Day. Each grade wears a different color. The self-segregation of students in the cafeteria is striking.

Day 12: Letter to Students (Sub Plans)

I'm home with my sick daughter today, so I don't have a picture. But I do want to share my sub plan.

First, I write sub plans as letters to my students. I feel it is more personal that way.

Second, we still have work and responsibilities as a class which need not be put aside in my absence. Whiteboard presentations will go on, and I can review the video and boards when I return to see if I need to give additional feedback.

Third is diagnostic testing. We do three: FCI, Lawson (hand scored version), and Epstein's math skills. This is the first year I've done all three, and I've spaced them out over the last couple weeks. It pains me to give up class time, but I am interested in correlations between the tests and growth over the year.

Day 11: Mini-Whiteboards


In addition to large whiteboards for group work, I also have a set of mini-whiteboards that were cut from tile board. I use them as low-tech clickers in typical Peer Instruction fashion.

Today we used them to make predictions about position-time graphs created by buggies in front of a motion detector. I love how students can answer more than just multiple choice questions using mini-whiteboards!