Due to parent-teacher conferences, an illness, and a unit test, it’s been several weeks since I’ve seen the Landon students. Today we got back into the swing of things and I gave my problem based lesson. They were on Friday schedule (instead of block), so I did the lesson with all of the classes. My theme was macroinvertebrates as bioindicators and I started by having the students discuss the terms macroinvertebrate and bioindicator. They did a good job of breaking down the words to make the definitions and we moved on to classifying the macroinvertebrates by pollution sensitivity. I put up three posters with pictures of macroinvertebrates to illustrate three different levels of pollution tolerance. These posters consisted of enlarged black and white pictures of macroinvertebrates. I didn’t want to overwhelm the students with all of the options, so I cut down each category to about five organisms.
After discussing what it meant if an organism was in a particular category, I told them that they were going to figure out how to use some macroinvertebrates they “collected” to determine something about water quality in that stream. Each table got a big piece of paper to record their thought process and they were handed a stack of macroinvertebrates to use as their sample. Their sample macroinvertebrates consisted of black and white line drawings that were enlarged to roughly the size of a playing card. Each group was given the same set . It was quite interesting to watch the groups work. Some groups just sat and stared and their piles for a few minutes, while other groups immediately began sorting them into categories (some started with species and others with pollution tolerance). The next step hem all they had done a great job with their reasoning and went on to explain the process of weighting samples. We then calculated the water quality and decided as a class it was good. I told them that citizen science teams did this very same thing across the nation. Teams collect macroinvertebrates, sort them, count them, and calculate the water quality index. I then asked them if they thought they could do the same thing. Every single class said no! I pointed out that they had just done all of those steps, and most of them changed their minds and said, “Oh! Yes, we could do that!” I did have one class that left unconvinced, though.
Overall, the activity went well. The students were engaged the whole time and it was fantastic to see the different ways they approached the activity. The wide variety of approaches was fascinating and a few students surprised me with their approach. A few groups did get a little grumpy because they didn’t have specific instructions, but Mr. Macha and I worked on asking them a few leading questions to get them moving along. We also reminded them that there was not a right or wrong answer, or even any set way to get to an answer. Instead, we simply wanted them to think about the problem and to come up with some sort of reasonable group answer. As I said before, most of the groups did quite well and worked steadily throughout the class period, so I consider this a successful lesson.