104 These are a few of our videos for analysis in the conceptual classes. The last clip in the video is in “instant replay” mode. Students will be producing several graphs and answering questions designed to help them connect projectile motion to the balanced force model and the unbalanced force model.





20121206-154655.jpg60 Today was an assessment. I liked the winter sun streaming in on an answer key and a beaker full of purple pens, ready for students to comment on their work. I am one of the many teachers who started doing this after reading Frank Noschese’s 180 blog last year, in which he described doing this with his students. Thank you, Frank!



20121129-154724.jpg55 Well, not everyone gets it yet. But, this class overall did better than the next class, which had less time to think about their mistakes and generally doesn’t discuss things at all. Purple writing is student commentary, red writing is my commentary.


Two for the price of one

I could not decide which class I wanted to talk about, so you get two photos today. The top one is from one of my conceptual classes, a great example of a mistake in which students assume that there must be some sort of straight upward force to balance the gravity force. This is the way all the FBD’s we made at first were laid out. In this problem, there should not be any surface force at all, which the system schema clearly shows. So we discussed that in class. I also spent time talking about how important this mistake was for everyone’s learning and in a later class I asked a group to add this particular mistake to their FBD, which they found distasteful but they did it anyway.

The second photo represents the successful use of Tracker to analyze a rotational motion video. I have a collection of 8 videos which I made several years ago and students have always done the analysis in Logger Pro, clicking through hundreds of frames. Ugh! Happily, last summer I learned how to use Tracker and all the groups were able to have Tracker autotrack a spot on the cardboard “record,” a process which wound up being painful in much different ways. I could go on and on about the technical issues we had but happily most of my students are resourceful and some are handy with tech support, so every group now has data to analyze. We’ll be doing that tomorrow.



I made a completely new version of Kelly’s “Practice 2” from the Balanced Force Particle Model. And by “completely new” I mean that I reprinted another copy for everyone, giving more space to each of the situations on the sheet. My students were unable to include the system schema, FBD, and force vector addition diagram in the space on the first version, and I felt that the system schema was pretty important. The conceptual-level  kids have a hard time doing the FBD without the system schema. So I made it a two-sheet, four-sided document and we are working through it focusing on balanced vs. unbalanced, directions of forces, and force vector addition. So far, so good. Assessment on Thursday!



50 Today students are using our ancient laptops to upload and edit video. Since for some reason Windows Movie Maker isn’t allowed to download the codec for .AVI files (huh?) we are uploading to YouTube and editing there using the “remix” function. It is a learning process. A few students are filming extra scenes, and a few more are trying their luck with the library’s computers to see if they are any faster. I like this project and it seems to have cemented some understandings about Newton’s first and second laws of motion for a number of kids, but video editing can be a long slow process.



39 First period has decided on some rules for how things behave. Pretty cool!





36 The conceptual classes are slowly working through a version of Kelly O’Shea’s packet for Balanced Forces. They were doing a decent job of the system schema diagrams and FBDs. Students were working on this in class in small groups, and each group made a whiteboard of the same material, and we compared them and looked for differences. We then discussed whether those differences were acceptable or if they made the solution incorrect.





Spring Force

35 Today a couple of classes were determining how much force it takes to stretch a spring different lengths. Before this year, I always did this lab in the energy unit, but I’m following Kelly O’Shea’s lead and doing it in the Balanced Forces unit. It’s a force, we are investigating it. We already investigated the gravity force.