### Leave Them Wanting More

Today I was substitute teaching calculus. A friend of mine is teaching one section of Real Calculus and two section of Calculus Lite. He had to go out of town to attend to an important matter, and he needed folks to cover his classes. Everyone wanted to cover Real Calculus, and he had to twist some arms to find subs for Calculus Lite. Since things are not all that busy at work these days, I told him that I would take one of the Calculus Lite classes.

The nice thing about teaching someone else's class -- especially on the second day of the semester -- is that it's OK to be a bitch to the students who are texting and web surfing during class. There are no real consequences; they can't hold it against me. I cited the official "success rate" for the course (not so hot) and warned them that they needed to keep up with the material if they expected to pass. I'm sure that a lot of the students who were not paying attention have already taken calculus in high school and don't really need to pay attention, especially for the basic stuff like limits that happens at the beginning of the semester. However, I'm of the opinion that if going to class is a waste of your time, you should just stay home instead of potentially distracting the people sitting around you. (My friend does not have an attendance policy.)

So today I spent 50 minutes talking about limits. How to find a limit from a graph and how to calculate limits.

Another nice thing about doing the second day of class is that it's really easy to work in some context of "why are we doing this." I spent a few minutes on "what is calculus" and what some of the important concepts are in the course and why limits are essential to calculus. This is much harder to do when you are deep in the heart of "here's yet another type of function that we can now take the derivative of." With my own class I can lay the history on pretty thick, but I wouldn't do that with someone eles's class.

And, of course the best part of substitute teaching is the "grass is always greener" effect. At the end of class three students came up to me and asked if I'm teaching Calculus Lite this semester and if they could switch into my class (nope, not teaching anything), and another one told me about how he took calculus in high school and how because of the way I explained limits this was the first time calculus made sense to him.

The nice thing about teaching someone else's class -- especially on the second day of the semester -- is that it's OK to be a bitch to the students who are texting and web surfing during class. There are no real consequences; they can't hold it against me. I cited the official "success rate" for the course (not so hot) and warned them that they needed to keep up with the material if they expected to pass. I'm sure that a lot of the students who were not paying attention have already taken calculus in high school and don't really need to pay attention, especially for the basic stuff like limits that happens at the beginning of the semester. However, I'm of the opinion that if going to class is a waste of your time, you should just stay home instead of potentially distracting the people sitting around you. (My friend does not have an attendance policy.)

So today I spent 50 minutes talking about limits. How to find a limit from a graph and how to calculate limits.

Another nice thing about doing the second day of class is that it's really easy to work in some context of "why are we doing this." I spent a few minutes on "what is calculus" and what some of the important concepts are in the course and why limits are essential to calculus. This is much harder to do when you are deep in the heart of "here's yet another type of function that we can now take the derivative of." With my own class I can lay the history on pretty thick, but I wouldn't do that with someone eles's class.

And, of course the best part of substitute teaching is the "grass is always greener" effect. At the end of class three students came up to me and asked if I'm teaching Calculus Lite this semester and if they could switch into my class (nope, not teaching anything), and another one told me about how he took calculus in high school and how because of the way I explained limits this was the first time calculus made sense to him.