Answers

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)

 

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Discussion

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! 😉

 

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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!

 

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How do you…

20 I actually took this photo so I would remember the questions from class to class, but it is just as well to use it here. Today the conceptual classes were working on how to go from one kind of representation to another. Notice that motion maps are missing. I decided not to use them this year and just focus on the graphs. I think it is helping my kids to have fewer things to focus on (in comparison to previous years).

In addition, we played the mistake game I mentioned yesterday. I asked the kids to look carefully at each velocity vs. time graph on a whiteboard and raise a hand when the spotted a mistake. It worked great in my 1st period class, with two distinct types of mistakes being made and good discussion on how to avoid them. But 5th period did not go so well, with a couple of kids who had missed class time and students who wanted to make the mistake a missing title or axis label. However, by then I realized I could use my iPad seating chart to record who had their hand up when, and now I have a record of the formative assessment. I keep each class’s seating chart in a separate Notability document, and I copy it and paste it when it gets all marked up and I need another. I will try to remember to write a longer post on my reflections blog to describe more fully how I use it.

 

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Connections

 

19 Today we started making the big connections (actually we did this yesterday with one class) between position vs. time graphs and velocity vs. time graphs. We got predictions for velocity vs. time graphs first, sharing them on the board at the front of the room, and then we used the motion detector to see  which (if any) of the predictions were right. Then with this one, which was the last one, I used the tools in Logger Pro to get points on my position vs. time graph and students calculated the slopes. Then I used Logger Pro to get the average velocities from the velocity graph, and the values were pretty similar to the slopes. Being able to do this and annotate it without having to walk back and forth between the board and the computer is one actual good use of the Promethean ActivBoard in my classroom. Finally, we applied the slope = velocity to draw a variety of velocity vs time graphs for a variety of position vs. time graphs. Sometimes practice is a very good thing! Tomorrow it will be “Mistake Game” time with the velocity graphs and then we can move on to using graphs to answer questions!

 

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Notes

18 OK so this is a little lame. I had an awesome day today, using ultrasonic motion sensors with the conceptual classes to match position vs. time graphs and discover what the velocity vs. time graphs look like. But I did not get any photos or videos of it happening, because I was hopping all around the classroom working with each group and making sure the graphs were set up correctly and fixing it when the velocity vs. time graph suddenly had a scale of -50 to 50 m/s when -2 to 2 m/s was much more appropriate. I had a good time, and I think students are starting to get it. This is in addition to the Super Ultimate Graphing Challenge that I had the kids do over the weekend, which helped some kids a lot with the position vs. time graphs.

Anyway, the photo above is one student’s notes from the motion sensor activity, which accidentally got left behind in class. Sigh. Maybe tomorrow there will be something more exciting.

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Car/Bowling Ball

12 My conceptual students are working on the constant velocity model paradigm lab. Some of them use a toy car (with either one or two batteries powering it) and some of them use a bowling ball they let go off a small ramp.

 

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