Wednesday, March 22, 2017

A Model Lesson

The best professional development I have attended this year was a day-long session on Modeling Education. For years I have seen information about the summer workshops offered by the American Modeling Teachers Association. I have wanted to enroll in one, but they often last several summer weeks and I haven't found one close enough to home that means I wouldn't be away from my family. That's part of why I was excited when local experts Holly McTernan and Jeremy Secaur shared their modeling expertise with many Northeast Ohio Science Specialists on March 1st.

If you are not familiar with modeling, I created the infographic at the left to sum up its big ideas. The basics include showing students a demonstration or problem or phenomenon and use it to set up an experiment, conduct the experiment, and then present results to the class. The teacher facilitates group activities and provides instruction as needed, often in small groups and through questions.

We worked through this cycle at a rapid pace so we could experience several sample activities. Here is a brief rundown of what we did:

1. Water height vs Volume: Each group of 4 were provided with a glass of a different shape (think tumbler, margarita, martini, wine glass, and so on). The instructions were to collect data about how much water we put into the cup and how high the top of the water was off the table. We had to collect 10 corresponding values, including our glass' minimum and maximum amount of water. Then we graphed it on a whiteboard. Then the whole group formed a circle, with whiteboards in hand but without the glasses. We were peppered with questions about our graphs. Does anyone see a place where the graph looks like the height increases by the same amount each time a certain volume is added? Why don't the best fit lines go through the origin on some graphs? What does your graph tell you about the relationship between water height and volume?

After this presentation of our results, we put our whiteboard graphs against the wall and were challenged to get a glass that we didn't use and try to match it with one of the graphs. Now I recognize that we were all science teachers (read: dorky by nature), but it was very difficult to get the group to stop talking about the graphs and glasses as our presenter tried to switch gears to the next activity. The engagement was incredibly high. Seriously, it was like a great date that you don't want to end!

2. Mass vs Cup + Objects: Each group is given an electronic balance, a cup, a set of similar objects (marbles, washers, wrapped candies, etc). There are two rules: You can't mass the empty cup and you can't put objects in the cup one at a time. Acquire 8 corresponding masses and number of objects in the cup. In my group, we put the cup with two objects in it on the balance and recorded the value. Then we added objects two or three at a time and recorded masses.

Then we had to graph our data and draw a best fit line and find the equation of the line. Then we had to circle up for questions again. What do we notice about our graphs? Why do our graphs look more similar this time? What do we think the y-intercept represents? What does the slope tell us? I was giddy as I realized that the slop was the mass of one of our objects!

3. Who wins the race? Our instructor posed a problem about two students who run a race at different speeds and one of them starts 1 second before the other. Who wins the race and when will they pass each other? We solved the problem, we graphed the solution on whiteboards, we presented our findings. My group solved the problem using a chart and a graph so we showed both. More questions.

4. When will they collide? Our instructor showed us a constant speed buggy. She also showed us a trick. Take one battery out and replace it with a wooden dowel covered with aluminum foil. Then replace it. This slows the buggy down and will make all the buggies go a slightly different constant speed. Genius! She let us make some measurements on her buggy for about 5 minutes. Then we made measurements on our own slower buggy for 5 minutes. Then she took the buggies.

She asked us to figure out if both buggies were released from opposite ends of a 2 meter track, where would they collide? We had to mark our prediction on the track and eventually we all tested it. Here is the video of one group's test run:

This was really fun. Our instructor suggested we graph it, but it made sense to me to use formulas, so I solved that way while other people used graphs. It was interesting to see several ways to attack the same problem. It was also exciting to watch the buggy test. Students would love this challenge!

My takeaways: I came home from this day exhausted and inspired. I realize that I do not use my whiteboards effectively and I want to change that. In fact, I bought a class set of these whiteboards so that I can start using graphs more. I don't have students graph or solve problems and share solutions enough. That's on my to-do list now too. I gave it a shot with a solubility inquiry lab, but it was only mildly successful. I need to keep working on it! More posts will definitely follow up on this!

1 comment:

  1. The first two experiments you did here are ones that most of us would skip because 'everyone knows' what the outcome should be. BUT DON'T SKIP THEM! Unless my high school kids are just woefully underprepared, kids to not enter high school (and in many cases they don't leave high school) able to make and read a graph. They can enter data and let Excel or Google Sheets make a graph, but they don't 'get' graphs yet. They need to spend time -- and for younger/less prepared kids a lot of time -- figuring out that slope and intercept of a best fit line (and area under it) matter. They need to process that way deeper than they want to, and without a bunch of time and effort spent on actions like this they simply won't. They need a bunch of this sort of experiment -- most of it with 'well-behaved' data, before they can really get good at interpreting a graph. I don't spend enough time on this part of my year, and it comes back to bite me later on, pretty much every year. Maybe I need to practice what I preach...