Monday, December 5, 2011

Concave Mirrors in Action

As a Physics teacher it can sometimes be difficult to picture ways to modify labs and make the content of the Grade 10 Applied Optics unit accessible to my students. I think that I have mentioned in a previous post that I really like the group of kids I am working with this year. A bunch of them are very curious and they ask good questions (even if they are off topic sometimes, you've just got to go with it!) and most of them are just trying to be successful enough to not only finish their Science credits, but to achieve a level 3.

One afternoon I was talking to a colleague about how teaching mirror and ray diagram rules are too complicated for these students and that I wish I could find a way to make them accessible through a lab and to find a way to create a meaningful summative evaluation. She inspired me to work on creating templates for the beginning steps of doing curved mirror ray diagrams to give them the chance to follow instructions for the actual rays while still giving them an understanding of the principle axis. I felt that a concave mirror would be the easiest way to do this.

The image shows the core diagram that was given to them for each rule (we did three of the rules). The instructions were put on the overhead (it is a good way to keep enough light in the room to not end up tripping over one another) for each one. The first set of instructions was detailed with specific areas to be labelled and fill-in-the-blank sentences at the bottom and was completed as a formative exercise (along with the second rule and set of instructions with slightly less detail). The following day we did the third rule, with even less detail and less support from the instructors, as a summative evaluation, and each student had to submit their own drawing (for the benefit of time each pair only had to create one diagram for the first two rules, unless they were speedy).

The students were engaged in the process and wanted to do well. Many of them asked to have the rubric so they could check over their work and double check that everything was included. The students averaged in a level 3 and were all very happy with their results when the rubrics were returned to them. I will definitely be seeking to involve more ideas like this when I teach this course again, and hope to be able to evolve it more and continue to use fewer "content-based" lessons throughout the unit. They seemed to have a decent grasp of the idea of a focal point, although they may have overextended this idea and lost sight of the fact that the third rule relates to the centre of curvature. A goal for increased understanding the next time I teach the course!

Hooray for collaborative teaching!

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