Today, I introduced the logistic function in my non AP class. We have been studying growth models, and the students were unsatisfied with the exponential model, so this was well timed. I had them get into groups and to explain why certain situations fit the logistic model. For example, one situation was the spread of a rumor that the other AP Calculus teacher and I are dating. I enjoy this part of the course because it reminds me of teaching Physics. You have to mix the concepts with the calculations with the implementations. It made me wish I was teaching Physics again!