Saturday, April 25, 2015

Kinematics Graph Checker

Here's an applet for kinematics (mostly CAPM) practice that I put together this fall. Students have the option to choose what information they are given, from these choices:
  • Initial x, v, and a values
  • Position graph, initial x values
  • Velocity graph, initial x and v values
  • Acceleration graph, initial, x, v, and a values
The length of the time interval considered can also be varied. After getting the given information, students can draw their predictions (either sketching the shapes or drawing quantitative graphs), and then press the "Show Solutions" button to reveal the hidden two or three graphs. I finished this one after students were through 1D kinematics this year, so I don't have any info on how effective students find these. Let me know if you like (or don't like) them for your classroom purposes!

Friday, April 10, 2015

What Can You Do With This? feat. Phineas and Ferb

I love the "What Can You Do With This?" variety of problem prompts: give the students a situation, photo, video, sound, or piece of equipment and then ask them: "what can you do with this?" That is, "what questions can you ask of this?"

Students have great ownership of these questions, and must really engage with the modeling process - identifying what principles apply, making and justifying assumptions and approximations, determining what information is available, etc., as well as practicing the process of asking interesting but focused and answerable questions. None of these purposes are served well by "textbook problems," not to mention that the process is more enjoyable and engaging for students when they're such a big part of it.

Here's my most recent - a video prompt that I saw while watching Phineas and Ferb with my son:

The students came up with some great questions, made measurements (including scaling) from the video, and did their analyses. It took about 35 minutes, and here are the three whiteboards from this section:
"What's the stiffness constant of the 'trampoline'"?
"What would his maximum acceleration be as he's caught?"

 "What's the maximum force exerted on him by the trampoline?"
Also explored by this group, but not pictured: "From how high could he fall and not die?"

 "How high does Phineas bounce?"
"How much energy was lost during the bounce?"