Monday, August 16, 2010

Common Knowledge?

I guess the moral of the story is Don't assume common knowledge:

Me: (addressing my honors 9th-graders...) Does anyone want to tell us how you estimated the distance from home to school in kilometers?
Class: [silence]
Me: Okay, that's a hard one. Let's see... (trying to figure out how to guide kids' thinking...) Well, what do you think is your average driving speed on your way to school? Like, if you drove for an hour, how far would you go?
Class: (rustling a bit, but still silent)
Me: Well, have you guys ever seen a posted speed limit around here? What does it say? 'Cause those are measured in kilometers per hour, aren't they?
Kid A: 30!
Kid B: I think 80?
Me: --Wow. Okay. So you guys have never seen a posted speed limit sign before.


  1. I have this same experience anytime I try to use a deck of cards to illustrate simple probability concepts.
    Once, I made the mistake of alluding to Hansel and Gretel in an English class.

  2. If they don't know H&G, how are they supposed to know that they can't just leave a trail of breadcrumbs when they go to the forest??

    ...That's like Forest Survival 101, in my book.