“If I had an hour to save the world I would spend 59 minutes defining the problem and one minute finding solutions”
- Al Einstein

Tuesday, December 7, 2010

Yo-Yo's and Calculus

     I like problems that make my students write their own equations, and we've been working with position, velocity, and acceleration recently. Yesterday, I had them write an equation to model the height of a yo-yo from the ground and then differentiate to find the maximum velocity. The situation lends itself nicely to writing a sinusoidal function, which was what I wanted them to do, really. We got to practice relating position, velocity and acceleration, differentiating trig functions, and using the chain rule all at once.
    The problem is, I don't think a yo-yo behaves sinusoidally. Neither did my students, so we tried to write an equation that worked better. Short on time, we wound up with the absolute value of a natural log (it moves quickly out of the hand, changes direction abruptly, and slows down on its way back up). For an impromptu activity, its going to segue nicely into finding the derivative of y = ln x... but I still want to find a good model for a yo-yo. I may head down to the Physics lab and see if there's an easy way to take some data, but I'm wondering if this has been done before (my googling reveals much more thorough models than we're ready for).

Monday, December 6, 2010

My Grading System

     I asked my students what they thought of my grading system (thank you, Google Forms). As I mentioned in my last post, I'm using SBG for the first time this year, and its exciting and nerve-wracking. Most of the feedback I've gotten so far has been positive, but naturally, I want to focus on the negative.

     Most student think that my system penalizes low scores on skills to heavily. They might be right. Here is the whole system, but the dirty of it is that if their score on any skill is a 2, they highest grade they can get is a B, even if every other score is a 4. If they have a 1, the highest possible grade is a C-.

     My reasoning is that if there is a skill that you have absolutely no understanding of (score of 1), then it should be your first priority to strengthen that skill. To raise a skill from a 1 to a 2 doesn't take much... I just need to see that you've got some clue what's going on and what you're trying to do. You don't even need to be able to successfully solve a single problem.

     If you're sitting on a whole bunch of 2's, then I'm pretty confident you're a C student. You can take part in the conversation and not make a fool of yourself, but you're not blazing the trail (usually). The real issue comes when a student has a whole bunch of 4's, and a 2 on one skill. They argue that the one 2 shouldn't bring their grade down to a B. I argue that they should turn that 2 into a 3. Is that too simplistic?

     I know there are so many other systems out there for converting a list of skills into a letter grade... Anyone have a favorite?

Wednesday, December 1, 2010

Tell 'em What They Know...

   So a colleague (who I will pretend is not the only one reading this) asked me about how I share my students progress with them. Apparently, he'd heard good things from students, which is nice, because I only hear about the bugs in the system. He also made fun of the fact that I took the crappy worksheets I wrote for when I was out of town and shared them with the world, saying that it wasn't very "21st Century" of me, so I need to dig myself out of that hole...

   I use Google Spreadsheet to keep my gradebook, which makes it "easy" to share my gradebook with my students. As you probably realize, high school students love comparing themselves to one another, so giving them access to everyone else's grades isn't a great idea (probably not great for job security, either). I'll try to explain in this post how I show each student only their own grades, and keep it updated automatically when I update... buckle up.

Step One:
   I published the gradebook as a webpage. This sounds terrifying, but no one gets the address. This is really the only way I could find to export the data to another spreadsheet (not just another sheet in the same file), which is what I needed to do next...

Step Two:
   When you publish a Google Spreadsheet, you have the option of copying a link to specific portions of it. I chose the column that represents each student's scores, and imported that into a separate spreadsheet for each student (be sure to "republish whenever changes are made". Now, every student has their own spreadsheet that has a list of the skills we've covered so far and their current score on each (I use Standards Based Grading, which many others have covered much better than I ever will). This is the tedious step, since I had to create a spreadsheet for each student... probably only took a couple of hours total, but its a lot of annoying cutting and pasting. Not fun.

(Here is where I learned to export (publish) and import into another spreadsheet. Much clearer than my explanation)

Step Three:
   This I learned the hard way: I hid the row that contained the original link to the published data. It turned out my students could click the link and see my whole gradebook. Not good, but luckily they told me about it early on, and I could fix it. Luckily, I had imported only the first row, then auto-filled the rest. Only the first row contained the link to the published data, so I could hide it and not worry.

Step Four:
   I gave each student read-only access to their spreadsheet. Vwah-la (French for "Holla!").

***Of course I would never be able to do this sort of thing without the incredible tech department at my school. They're a great resource that I know most teachers don't have! Thanks, guys!