I didn't write a blog for Friday; it was a test day.
Today, I passed back the test. I wanted to point out a particular problem that almost every student missed. The problem didn't look like a problem we haven't really done, and I just drew a simple diagram of the problem. Over half the class immediately understood the answer. The problem I have is too little meaning making with drawing and too much WTF. (WTF stands for What's the Formula.) I really like this problem, and I don't want to say much more, because I want to use the problem for a few more years, and I know at least one student (Hello from Walmart!) is reading this.
After going over the test, I wanted to show more of the power of drawing:
We are building slowly to a way of drawing constructive and destructive interference in two dimensions.