Today, I was grading papers from the day before, when I came across an interesting problem. I used a common technique to teach my students some new information: accessing prior knowledge. Unfortunately, this completely backfired. I was trying to help them to learn about Copernicus, and somehow accidentally taught them he proved the earth was round. Not only that, but one student seemed to think that he "proved the earth is flat!" I don't even know.
I learned that I need to be careful when accessing prior knowledge. Apparently it can accidentally confuse your students. I guess everyone focused on the earth being round instead of the earth orbiting the sun. After today, though, I have to say I really felt like I failed some students...especially if they are under the misconception that the earth is flat. Ironically, in teaching about the middle ages, I may have accidentally set some students back to that era of mentality.