# “if you get this, you can go home”

Posted on September 19, 2013

Attending a thoroughly engaging class has the same effect on me as reading a thoroughly engaging book.   I carry its voice with me for a while.

In CSC 140, Java,   yesterday we heard and saw a meticulous explanation of how object reference variables work and how important it is to understand that the variable name holds an address, not data (as primitive variables would). I think I’m going to make a pencast from my notes to entertain myself on my commutes, and perhaps sharing it, which would mean  figuring out how to make a PDF from Livescribe and finding my jou8rnals… but it’s *not* an easy find.

… and it’s having an impact.   It’s easier for me to explain, one (or seven) more time(s), that “raising i to powers works like raising -1 to powers,” and showing it,  instead of getting the “dang it! Don’t you know this yet?!?!? I *told* you it was important!”   edge in my voice.  If the student is down here, they’re trying to learn it.  Dragging fresh paint over the rotted wood is only a temporary fix.

More than that, though, it means that I’m working in concept-building interactions more often.  When the student wants to know how to set up “what are two consecutive odd integers whose product is ____?”   I remember that one of the more insidious conceptual potholes is lack of  understanding that “x stands for a number — and could be any number until we put constraints on it,” and I’ll walk through examples of “next even number” so they figure out that it’s 12 + 2, 30 + 2… and I’ll mention that since it would work for any number in the universe, we can just say “x + 2.”   (Now to figure out how to do that so it’s not just me talking…)

I am deeply appreciating approaching  learning from “this is what you need to understand to prevent bad mistakes later,” instead of “DO NOT MAKE THIS MISTAKE! DO NOT MAKE THIS MISTAKE!”  as Salman Khan’s “lesson” on exponents does, in which he tells us many, many times that it is NOT 6 x 8, it is NOT 48, though it is 6 and 6 and 6 and 6 … (exactly the same language he uses when explaining multiplication), and  he never actually calculates what 6^8 is…   I want to understand how and why to figure out how to make a Class, so I’ll be  performing the process that gets to a good answer, instead of plowing through the important concept so quickly that I simplify it, and then finding out what mistakes that taking short cuts  cause (but not why), and  trying not to make them, but having to figure that out at every level, having no fun, and becoming convinced that I shall always be making mistakes.

We heard two or three examples, and were implored to get colored pencils to make the visual descriptions (oh, yes, did I mention use visuals and not just words?) ourselves…  I shall henceforth call this “Conceptual Frontloading” and because it has a jargon name, it is therefore meet and right.

And, henceforth, I shall endeavor to figure out how to do it for operations on negative numbers, because students are  out there bein’ knocked upside the head with them right now, and … yes, we tear through “adding negatives is more negative — so two negatives don’t make a positive’ (except in a way they do, in that if you’re writing down what you’re doing you’re going to + the two absolute values)…. and we do kinda give it the “DO NOT MAKE THIS MISTAKE!” and “here’s a trick so you don’t make the mistake” approach instead of “let’s totally get this, so you can understand how *that* would be a mistake.”