Projectile Motion Map

20130226-144356.jpg108 This is another colored-pencil activity I do with my conceptual students. We start with just the vertical motion and then put it together with horizontal motion. Everyone in the class winds up with their own copy made with their own color choices.

I used to do this with transparencies on an overhead projector, having photocopied graph paper (red line graph paper, not blue line graph paper) onto the transparencies. I think maybe I ink-jet-printed a couple of transparencies, too. Those water-soluble markers would then get all over my hands, where they were suddenly no longer water-soluble. (WHY???) Anyway, then after a year or so of using the Promethean ActivBoard, I discovered how to put a grid on a page in a flipchart. Bye-bye transparencies! Now I only get out the overhead projector when I need a bright light source for something.




Free Fall

102 When we investigate free fall, we drop picket fences, and we also fling them upward using rubber bands. This does not work every time, but it is quick enough to get five good trials with usable slopes. We compare the slopes of these graphs to the slopes of graphs made with the dropped picket fences.


Fan Cart

94 The conceptual classes are going to determine how much force a fan exerts on a fan cart by comparing acceleration to mass. I have never tried this before so it will be interesting to see how it works out. Each group has a video with a different amount of total mass. They will get acceleration from video analysis and then we will make a whole-class graph. Maybe all three conceptual classes will contribute data to one graph with lots of data! Ooh!



20130104-130620.jpg74 My 5th period class had some great results from their practicum with the coffee filters. One group got a time only 0.04 seconds off their “given” time, and another group (shown above) got only 0.01 second off their “given” time! Wow!


Coffee Filters

20130102-131014.jpg72 Starting off the new year with a lab. This is a coffee filter drop lab, in which students model the motion of a coffee filter from data they take in class, then they predict how high they would have to drop it from in order for the filter to take a given amount of time to hit the floor. The tricky bit is the room is less than 3 meters tall, and invariably they calculate a height greater than 3 meters (I’m sneaky about how I pick the “given” times). We have to go out to one of the stairwells to test the prediction. A good model results in a drop time within 0.1 s of the given time.



IMG_20121219_14145969 Some lovely kinematics graphs in preparation for tomorrow’s assessment.


Preliminary Graphs


58 So, the data from the videos is not bad! Not everyone has actually managed to collect the data yet, however, as some students have technical difficulties. I’m always amazed when students can’t figure out how to find a file or save a file. I expect by the end of the year my students will have it figured out! I have found that it is important to have all the kids doing individual work for things like this, or only one kid from each group will learn how. One year I had students join my class mid-year who had somehow managed to always get others in their groups to do their work. My kids straightened them right out in terms of using the computers!



25 One thing I have noticed is that the Modeling Instruction materials for physics do not have a lot of practice materials in them. Practice is what helps you get better at things (it builds myelin layers around the circuits in your brain), so over the years I have made various practice materials for my students.  Today we were getting ready for tomorrow’s assessment of x vs. t and v vs. t graphs with my conceptual classes. So last night I made some practice problems. I drew them by hand on graph paper with a sharpie pen and a ruler, which was much more relaxing for me than trying to create them all on the computer. Doing it on the computer is easy enough with OmniGraphSketcher and Excel, but drawing these out by hand is very soothing for my brain. Soldering is like that too. I am perfectly happy to sit and solder for hours at a time.

Anyway, we did not get to go over the answers in class, so I made a colorful answer sheet, scanned it, and put it on Moodle. I hope the different colors help the students get which parts are which. The photo above shows two of the six “problems” I gave the kids.

Also, it was “Disney/Pixar” day at school for spirit week:

(Army guy, Buzz Lightyear, shiny Superman (?), Dalmation, Elastigirl, kid from Up, ?, Cheshire cat, “Kitty” and in front is Hercules)


##CVPM  ##graphing




22 My first period class made my day on Friday. While a few students worked silently by themselves, the rest divided into two groups to look at a set of graphs and answer questions. The graphs were originally given as x vs. t graphs and earlier this week the kids drew the corresponding v vs. t graphs. We were looking at the graphs again and these were the questions:

  • What is the total distance?
  • What is the total displacement?
  • What is the average speed?
  • What is the average velocity?

The two groups were awesome. They had good discussions. They asked each other questions. They explained things to each other. The video clip above isn’t the best discussion I heard, it’s just the one I got to with the video camera and which then had the best sound quality. Another group had even better discussion, with better participation among the group. Unfortunately, I could not make out what they were saying once I looked at the video.

I’m sorry this post is two days late. I think that may wind up being par for the course if I wind up with more videos. Deal with it! 😉


##CVPM  ##graphing  ##studentdialogue

Sample Assessment

21 This is today’s assessment. You may recognize the graphs on page 1 from some of the mechanics Modeling Instruction materials available on the AMTA website. But I changed the question to fit my intent.

This student did a great job. Some students are still completely clueless. So we have some more work to do. I want to have an archive of practice problems for those kids who really need a lot of practice to get some things right. A lot of practice to build up enough myelin so that they can read a description of motion and make a position vs. time graph. If you look at the second page, I had a lot of kids who could draw the correct shape of the graph, and most of them even started the graph at the point (0s, 5m), but very few were able to put correct slopes in. So, more practice!


##CVPM  ##assessment