Yesterday, I tried to kill inquiry class. Thankfully, I tried to kill it just before our 20 minute break, and it gave me some time to think through what just happened and where we should go next.
The first thing I did to try to kill inquiry class was to have too many groups share their whiteboards out to the class when we didn’t need to. See, they had spent time last week predicting and observing what happens when a long bulb shines through a filament bulb; then for homework they had spent time explaining and reconciling their predictions; then we started class by having small groups share their homeworks with each other and try to construct a consensus explanation. … By the end of all that, me having each group then share out to class was just too much time spent on the same thing. We were bored, and too many of drawing were similar. I easily could have had one or two groups share out, and be done.
So what pressed me to have each group go? To me, I still saw minor differences in their thinking about what happens when that I thought needed resolution:
- Was long bulb through the triangle hole showing a stretched out triangle, or a stack of triangles, or a triangular prism? Was the light from each part of the bulb going out in one direction or many directions?
So to top it off, after they were done sharing, I spent another five minutes talking about it. When I saw talking about it, I should say I was talking to them about it. See, I was planning and hoping to shift our investigation from how light shines through holes to how does light bounce of surfaces.
That was my agenda: I wanted to get us to a place where we would start to see objects (like a tree) much in the same way we see the long filament bulb. To do that, I thought we needed to pin down how the long filament bulb worked and then investigate how light bounces off materials. One group had already proposed the need for two different kinds of bounces, and I thought we could follow up on that. I foreshadowed this direction just before break, and class felt like it had been run over like a truck.
So during break, I thought about what might be a better direction to go, one based on students’ interests and ideas over the past few weeks, rather than my own agenda about what to do. I thought about how students had brought up the inverted spoon image, and I thought about how any other group had proposed that the box works like an eye, and another group had decided that the box might even work similar to a camera. Just that morning, I had had a conversation with a pair of students about the eye. One student had printed out some information about the eye over the weekend, and we were discussing the parts of the eye. As we talked, we got interested in the fact that our box theater doesn’t have a lens, and that it would be interesting to find out why the eye needed a lens, especially since our boxes work without a lens.
So when break was over, I told students how I was changing the plan. I told them how I thought we had a pretty awesome explanation for pinhole theatre, and how that investigation had led us to some rules about light that we should test out with other things we are interested in. I told them that I thought each group should decide what they would like to investigate next. I reminded them of our interest in spoons, and how eyes work, and how cameras works. I also gave them the option of exploring how light bounces off different materials. 2 groups decided to investigate some lenses I had pulled. 3 groups decided to look up anatomical information about the eye on the internet. And one group decided to investigate with curved mirrors.
The group with the mirrors played around with the mirrors for a while, and based on their ideas, I decided to give them a laser pointer, for them to see how light bounces off the mirrors. They found that the some mirrors cause rays to cross, and others cause the rays to go out. For one mirror (which was a thin strip of curved mirror), they mapped out exactly where the lines cross by tracing over where the laser pointer glanced across a piece of paper. They did it both for a concave and convex, and showed how the light bends in for one and out for the other. They also had a really exciting discovery: See our thin curved strips of mirror are reflective on both sides… and I don’t know what led them to think to try this, but they found that if you shine one laser into the concave side and one laser into the convex side at the same point, the laser bounces off in just the right way so that the two lasers lines form a single line. Pretty cool.
The group playing with the lenses discovered that lenses do different things at different distances. They can make things bigger, they make things blurry, or they can make things upside down. This led us to wonder about the eye: is the lens in the eye making things bigger, blurry, or upside down. Some of the groups, are excited that the lens might flip the image again after the hole has flipped it, so that the image formed on the retina isn’t upside down. Other seem certain that the image is really upside down on the retina. The group who looked up stuff on the internet helped us to map out the analogy between the eye and the box. We now thinking that the hole is the pupil; the paper in the box is the retina; the aluminum foil is like the iris. We’ve decided the box doesn’t have a cornea or a lens, and so we should figure out what that stuff does.
This seemed to, for the most part, get us back on track. And, got us thinking about how light does different with different materials anyway, which was kind of the whole thing I wanted to do anyway. Sure, right now, no one is investigating the issue of two different kinds of bounces, but that’s OK. That’s not what we needed. What we needed was a sense of purpose.
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