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Wednesday, September 15, 2010

First Foray into Modeling whiteboards.

Today began the first time we discussed results of the mini-labs on the whiteboards. It was a dissappointing start to say the least. My first hour was very distracted and it was like pulling teeth to get them to answer questions and think. My second hour I think I was better prepared and I introduced the activity a little differently and I had better success. My 5th hour was even better yet. As Steve pointed out in his blog the other day, I still have difficulty sometimes with being stupid. I still want to answer sometimes or encourage the "correct" answers.

I noticed on one board my students had used a different number of sig. figs. for each number in a data table. I thought that was a great opening to discuss that topic. Unfortunately the consensus at the end was sig. figs. don't matter... I guess I will have to re-visit that topic. I don't really care if they know all the rules for sig. figs, I just want them to realize that the sig figs demonstrate the precision of the measurement.

My students got really restless during the activity after a while. I decided to stop and pick it up again tomorrow. Maximum of 2 per day right now until they start to get used to the dialog.

Coolest moments? One group of ladies in my 2nd hour did the diameter vs circumference of a circle and got a slope of 3.1423! How close is that? I barely had to prompt them to figure out what the number was. Two groups in my first hour did the wire lab, data was different for each one because they used different cuts of the same wire (I had two stations running). Their line equations were nearly identical. I was amazed.

Biggest problem? I made 25 whiteboards. 10 needed per class. If I don't get to all the labs and I save them, I need to have more. Back to the depot I go...


  1. I decided to do the wire lab as our first real white boarding exercise. It went pretty well, but I limited to one group for presentation because of time constraints. I figured that after putting one group "through the ringer" everyone would have a better idea of what was expected on the boards. I also didn't want to spend any additional time addressing what would end up being similar questions for each group. I'm in the middle of the Pasta Bridge Lab and hope to make it around the room. I will start the mini-labs early next week (already behind it seems...the pressure is building). However, I'm hoping that the extra time now will result in more efficient sessions later as they become more familiar and comfortable with the process.

    Overall, the response has been pretty good. The students are definitely working outside their comfort zone. I sense they're wondering where this is all going...but they have been surprised to pick apart a simple slope equation and discover some things they had never really thought about before.

    I struggle with the instructions for the lab though. I feel like I don't want to be too specific, but without some direction I feel like we're burning daylight. Specifically with the Pasta Bridge Lab, I laid out the materials that were available and tried to generate some discussion about how they could be used to create an experiment. That had them spinning. The next hour I gave some more concrete objectives and things proceeded a little better. They still had to come up with the experiment, of course.

    I am fortunate to have students who received a good grounding in sig figs in Chemistry. At this point, it is a point of brief discussion to check their understanding but I don't want to spend too much time on it. It will come up again and I think that's a much more organic way of handling it.

  2. How have you approached the slope issue. We whiteboarded the mini-labs and on each one we discussed the slope of the line. Some of my students are starting to warm to the idea. Most are really confused. I keep assuring them they will get it, but I can see them struggling. The good new is that in today's session, the students actually started asking questions and making comments. The excruciatingly long wait times I am doing are finally starting to pay off!

  3. I guess that I'm fortunate to have honor physics students, so they have a pretty good (but not complete) idea of slope. We are just finishing up the WB portion of the pasta bridge lab. I did get some fractions, which gave me the opportunity to discuss fractions vs decimal values and which is appropriate for science discussions. However there were some interesting looks and answers when I started asking questions about their regression equations - What are the units? What are the units of the coefficient? What are the units of the y-intercept? Does the negative y-intercept make sense given your experimental setup? They have never been asked to really think about these things in terms of an actual physical system so it's definitely messing with their minds (in a good way, of course). But I think they are getting the idea.

    I had a couple of students test the relationship between the size of the gap between the tables and the number of marbles it could hold. One group found an inverse relationship, as expected, so the data fell along a nice curve. The equation made sense in terms of the experiment. They could put the equation into a sentence that made sense. Another group did the same thing and used an exponential function for their curve. They were stumped when I asked them to turn that one into words. On Monday we will do a comparison between the two before we wrap up the discussion.

    As I move into the mini-labs I will start to try to draw in student questions. Thanks for the heads-up about using wait time for that!! Are you able to do this in a circle discussion? Do you have all the boards up so everyone can check them out while one of the groups are presenting? (I have to figure out a way to do the circle!!)

    Overall, I think they're getting the hang of what we're doing. I think my kids are getting a little nervous wondering when the real physics is going to start! ;-) I'm really looking forward to starting linear motion.

  4. Jim, I did a modified circle. My room is really long but narrow and I have found it difficult for the groups to look at everyone's boards at once. So I have the groups who are presenting go to one of the narrow sides so we can all see. Since everyone's lab was different I only did one at a time. I have contemplated trying to find some really wide velcro and seeing if I could hand the boards from the wall around the room. Once I win a grant I will try that. Too expensive for my pocketbook right now.

    Frank, the wire lab is one of our "mini-labs" that we did in our workshop. They are super quick easy labs that just start showing the relationships between factors and is a first chance for the kids to start graphing. I did: the wire lab - length of wire vs. mass, Carpet lab - surface area of carpet vs. mass, Sphere lab - diameter vs. volume, Circle Lab #1 - diameter vs. circumference, Circle Lab #2 - radius vs surface area, Balance Lab - Mass added to a lever vs distance from fulcrum to balance out a counterweight, and a pendulum lab - mass vs. period.