I planned to teach vectors on Friday, and I must have been super sleepy as I prepared earlier, because when all was said and done, it took less than an hour to cover what I needed to, and then I had 30 minutes left to fill with no plans.
Box and Whisker Plots to the rescue. We'd just discussed (as a department) how these will be on our state exit exam for the students and how they hadn't seen it since 8th grade. I cobbled together a lesson to show them what's what and how do do things on the graphing calculator. In my first class, we gathered number of hours slept last night, and worked with that data. I didn't like it so much since the numbers only ranged from 4 to 10. I polled my next class about what they wanted to count that had a wide range, and after some mis-starts, they came up with number of hours of T.V. watched in a week. Sheesh, that was illuminating. The numbers spanned from 3 to 30. I had to keep reminding them and myself to make no judgmental noises or facial expressions when someone called out their number.
As I still had time left, I asked them to figure out how to change the data without adding more data so that the box was wider. That got their minds working.