## Tuesday, October 5, 2010

### Breaking the Silence Seal on Precalculus

I haven't been writing much about Precalc, because we're sort of just reviewing skills they should already have from previous years, that they still lack. Nothing really exciting.

I am breaking the silence seal, however, because I decided to have my kids each build a catapult a la Sweeney Math, leading up to the catapult math project.

The only tricky thing about that is that we need to build the catapult piecewise, to allow each part to dry overnight before adding on the next part. So, meanwhile (during this multi-day assembly of the parts), kids are doing some very necessary quadratic algebraic practice on the side. Today was Day 1 of building the catapults, and it went really well! :) They got the front half of the catapult done (minus the guard rails), and we put old Geometry and Calculus textbooks diagonally on top to hold the pieces in place as they dried. I checked back a couple of periods later, and only had to make small glue adjustments on a couple of the catapults. Score! (I also had every kid make his/her own, that way we can choose the best catapults to use for the math part, and every kid can take home a catapult in the end.) :)

I am excited about this. I have yet to test the math out, but I think that for the math part, I am going to simplify the quadratic math involved to use only standard-form equations instead of the vertex form. See my comments on this post if you're curious. Should end up being the same idea, and hopefully with the same accuracy.

I didn't take a picture of this, but I made Geoff build a catapult alongside me last week, and OF COURSE he's not going to just build the given simple design. In the end, his looked way more complicated (had clothes pins upside down and sideways) but shot significantly farther than the simple design I'm giving my kids. He's so hard-wired to be an engineer. :)

#### 1 comment:

1. I read your comment about finding v when you have 0 for the height (after several trials). Could you tell me more about how you did this? Do you also plug something in for Y? And what does Y represent in the equation y=1/2gt^2 + vt + 0?