## Tuesday, 15 April 2014

### MFM2P - Day 42

Day 42

We started with elevator and bubble wrap estimations from Estimation 180, having skipped over the Christmas ones (despite the ridiculous snow today, it is not Christmas). I notice that my students' guesses are getting closer together - less crazy high and crazy low ones. They sometimes all underestimate or overestimate, which is interesting.

Next up: staircases from Fawn. I used this as an introduction to slope. You should read her post, really, go read it now, it's better than what I did! This activity was a great way of getting students talking about steepness and it was really interesting to see how they tried to measure it for #5. This image is from Fawn's blog:

As a class we looked at whether only the vertical height determined steepness or only the horizontal portion determined steepness (I provided diagrams as counter-examples). We agreed that both were important. I asked how we could get one number to represent steepness and, because I had an example with height and base width as well as step height and step width, one student related it to scale factor (which was awesome).  I used to tie both to ratios. We settled on finding the ratio of height to base length which they did for the remaining examples and then we wrote our new order of least steep to most steep. I moved on to mentioning the word slope, but we did not get further than them gluing some slope pages in their comp books. We will continue this tomorrow.