I deliberately teach topics in a different order in my AP class and in my non AP class because it gives me a chance to reflect and give it a try later in the year. We did related rates in November or something for AP, and we are doing it now in non AP. Sam posted his materials for Related Rates, and this really help me reorganize my unit. We started off today just by drawing what a circle with a constantly increasing radius would like, and what a circle with a constantly increasing area would like. I think this was a nice intro because I noticed that whenever my students draw diagrams for Related Rates problems, they make them somehow reflect that the object is changing, which is something I've never really seen them do before.