# f(time) at dy/dan

Dan at dy/dan has a neat intro lesson on graphing. In short, he gets the kiddies to graph elevation vs time for a series of events that he has videotaped. He has rewind, and slow motion, and it sounds like they get it….

He has offered to send the neat materials to the first 20 bloggers who link the post. Let’s see if I make it under the wire.

Me? I graph street vs time (using 2nd Avenue, and pretending its not one way, since we need a 1st Street.) We graph a cab’s story (lights, stops, traffic), and then graph some linear motion.

(more below the fold —>)Nice piece about it – it becomes a reference problem for the whole unit: y-intercept is starting point, slope is speed (negative speed is downtown, 0 slope is when you are standing still). Vertical lines represent two places at the same time – impossible, which matches nicely with an undefined slope. Parallel lines have the same slope, and people moving at the same speed don’t catch each other. And a point of intersection is when two objects reach the same point at the same time (Abner leaves 9th street, strolling uptown at a rate of 2 blocks every 3 minutes. At the same time Betty leaves 1st street, running uptown 2 blocks every minute. When and where will she catch Abner?)

Anyway, I like this one. But Dan’s seems cool.