Category Archives: Uncategorized

Pinhole Camera for Modeling Instruction Unit 0


I recently got a lot of responses about my use of a pinhole camera as a lab to introduce functions and curve fitting during Unit 0, Scientific Reasoning in modeling instruction.

Here’s my original post:

As another introductory lab for the scientific reasoning unit, I made some pinhole cameras from two boxes that could telescope inside each other so students could adjust the distance from screen to the hole.  Students think the camera is cool, so it’s a memorable lab, you can get linear, inverse, squared and inverse square curves from the data, depending on how far you want to go with it, and the meaning of the trends relates to directly observable sizes of the object or the image.  To get the squared fits, you find the area of the image by box counting, which reviewed the concept of area.  All of this proved very useful later in the year, as they actually remembered the lab, and could think about whether sizes were increasing or decreasing to help recall the association between graph shape, equation and meaning.

I used the circle lab as a follow-up, and  I still like it, but the students just don’t tend to remember it as well.  Other labs such as the pendulum or a bouncing ball are memorable, but the relationships are more abstract and the students don’t seem to hold on to the visual picture of them as long, so they weren’t as good of a recall aid.

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Announcing the Summer 2015 Kinematics Robot Workshop

I am pleased to announce that the science house at NC State University (Raleigh, NC) will be hosting a summer workshop featuring the kinematic robots and curriculum I have developed over the past few years. Mike Turner and I will lead participants through the kinematics robot curriculum developed last summer in modeling workshop format – with participants alternating in roles as teacher and student. Here’s a link to the registration page. Cost is $400, which includes a license for the software, and $600 with workshop, software and two robots. Low cost housing is available nearby on campus.

New Article in The Physics Teacher, New Software, New Curriculum, New Summer Workshop, and More!

Much has happened in the two years since I last posted to this blog.

  • After input from users, the software to run the robots was re-written and updated with new features.
  • The Science House at North Carolina State sponsored a summer workshop through their summer modeling institute program.  It was attended by almost a dozen experience North Carolina modeling teachers, who went through every activity alternating in student and teacher modes modeling workshop fashion and gave it a thorough critique.  Every single activity was revised based on their input, new exercises were added and the sequence was altered to be more effective.
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A Living Position vs. Time Graph

I originally set up this exercise to demonstrate squared vs. linear scaling rules long after my kinematics units were done.  I was going to just program a constant velocity and constant acceleration robot, and run them side-by-side for 1 second, 2 seconds, etc. with discussion in between.  Then I though it would be easier to program several robots with the set times and just swap out robots.  When that was done, I realized i could run them all at the same time, and low and behold they created a living position vs. time graph!  This will definitely be my introduction to position vs. time graphs for accelerated motion next year.

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Featured on the Global Physics Department

On December 12th, I spoke to Andy Rundquist and other physics teachers at The Global Physics Department virtual meeting.  I demonstrated using the graphical user interfaces, and responded to some excellent questions about the project.  It covers some different ground about the capabilities of the robots and the programs and why the project was designed the way it was.  Very informative.

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Chasing Dingo Dog by Silly Eagle Books, on flickr

Turning Classic Physics Problems into Lab Practicums: Featuring the Patrolman and the Speeder

… encouraged by the testing of their solutions with the robots. They wanted to see it really work, and went back with enthusiasm to search for a more accurate method or to track down errors in mathematics.

Over beers at late night physics teacher gatherings, conferences like the American Association of Physics Teachers (AAPT) or Physics Teacher Camp, it seems someone almost always pipes up to say, “I just love lab practicums. They’re great! I wish I could do all lab practicums rather than textbook type problems.” Well, I and a collaborating teacher just turned some classic physics problems into lab practicums using my reprogrammed Scribbler 2 Robots. First is the patrolman and speeder problem, a great student exercise because it lends itself to so many different problem-solving approaches.

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Robot Copycats (or Matching Graphs)

I knew from their graph what would happen, but didn’t say anything. I didn’t have to. When the students saw the robot go fast, then slow in segments 2 and 3, they commented “It’s opposite.” … And sure enough, they were then able to correct the issue themselves with no intervention from me.

This summer, I reprogrammed the Scribbler 2 Robot from Parallax Corporation to be a physics apparatus.  (I intend the robot project itself to be the subject of a future blog post.). In this post, I describe three similar lab-practical exercises with the robots. In all three tasks, students programmed a robot with a graphical user interface so that it’s motion matched another robot. In the first, students programmed their robot with a position vs. time graph so that it matched one programmed by me. In the last two exercises, they programmed a robot with one graph (position vs. time or velocity vs. time) and the second robot with the other.

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Position vs. Time Graphical User Interface

Giving Robots (and Students) a Head Start

“So we should just play with this, then!”

This summer, I reprogrammed the Scribbler 2 Robot from Parallax Corporation to be a physics apparatus.  (I intend the robot project itself to be the subject of a future blog post.) This lab practicum is the student’s first opportunity to program a robot themselves. Each group is given two robots, one programmed in advance by me that students studied in their first robot lab, and a second one which they must program themselves through a position vs. time graphical user interface. Students must understand how a position vs. time graph describes motion in order to get the robot to complete the assigned task.

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Robot Races

The Robot Lab (formerly known as the Buggy Lab)

Just the simple ability to program the robots with a range of clearly distinct speeds was a productive supplement to the traditional buggy lab.

In physics modeling instruction, the constant velocity particle model begins with a paradigm investigation of the motion of constant-speed buggies. This summer, I reprogrammed the Scribbler 2 Robot from Parallax Corporation to be a physics apparatus , and this was my first chance to use them. (I intend the robot project itself to be the subject of a future blog post.) For the robot lab, I programmed the robots to have speeds from 10cm/s to 18.5cm/s, but all to go 150cm before stopping.

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Microcosm (definition): 

a community or other unity that is an epitome of a larger unity (Meriam Webster Dictionary)

I use the word microcosm to refer to a classroom of students acting as scientific investigators to construct and deploy the laws and concepts of physics.  The classroom is a microcosm of the larger scientific community. 

I also use the word microcosm to refer to the use of technology to create a limited physical world, within which students can explore independently and figure things out for themselves.