The parabola thing

My innovative lesson idea has been a monumental failure.

To spice up working with parabolas and quadratic equations, I built a set of vertical posts, and had students work in groups to measure length and height of various points on the parabola created by a string hanging between the posts. The students loved it, said it was a lot more fun than usual, etc. The following day, I used a Keynote presentation (which is like PowerPoint, but made my Apple) to demonstrate how to translate the data table, so that the vertex was centered at (0,0). That was a bit of a conceptual struggle, but kind of came together okay.

Today, the real suckage began. Trying to model the actual data, and find a coefficient that would fit the general y=ax^2 form. 2nd period did relatively okay with it, getting at least to where at least one person in each group was able to find their a-parameter. But I couldn't help but feeling like I was making the whole thing sort of mystic (nobody asked "why are we just lopping off bx+c?", but in my heart, it hurt a lot to say "let's just work on this bit, y=ax^2"...) And there's no homework tied into the project, and the work that I grabbed out of the book to have homework for homework's sake was way out of reach, and ended up confusing people horribly (and probably wiped out what gains were made earlier).

So, the upshot is: the plan of the nifty fun activity itself, I do okay (though, I have to admit, I wouldn't have wanted to use the measurement lesson as my NBPTS video for group work-- not enough questions and answers involved in the project). Now I need to also plan around the activity: homework, extension, assessment.

But, if it weren't hard, I wouldn't love doing it.