## Thursday, September 10, 2015

### Day 8: newtons revenge day 2 & quadratic functions gallery walk

Today was estimating a small tissue package a lot of students overestimated. One student said they thought that three tissues equals a pencil and it looks 3 pencils high so 3*3=9. It end up being 10 and we talked about 100% error 0% and 20% error.

Cpm guides students through human error in the scatter plot sticky dots  (inaccurate graphing or not adding the 100 cm to the meter stick below.

Students observed from their graph if your reach depends on your height. We discussed students with the same height but different reaches. Intro'd independent and dependent data on the axis. Students are many times unsure of describing the trend of the data. I made the analogy of a science experiment with plants with various hours of daylight and their heights as the dependent variable.

The next part was analyzing the inefficient scaling of the graph. Students understood it wasn't a 4 quadrant graph because there are no negative heights or reaches. Then if you should start at 0. Some told me about the discontinuous graph with the squiggle. Also why did I skip count by 25 instead of listing all the heights. Students volunteered it needs to be even and a pattern or numbers. I tried to stress why you can't have 160 161 then 163.

I asked students if it was safe for all of them to ride newtons revenge. They said yes because all of us are under 200. I asked where. And they said on the y axis. This wasn't visible on the premade graph but students were able to tell me on desmos during closure to make "the death line" as one student put it.

Then they are asked to see if the ride is safe for 228 cm tall Yao Ming. Some students graphed their groups measurement on their own graphs. I shared one under doc camera one of the periods. Though in 5th a student Nicole and Frankie presented their ideas to the class that they subtracted the reaches from the heights to find the differences and then average them. They got 40. They subtracted that from his 228 cm height and concluded that it was safe.

I showed my students how to copy and paste the data into desmos. This was the second representation that proves the safety of the ride.

Note to self. I forgot I could have done regression with y1~mx1 + b (all subscript numbers). Also to use projector mode to make interval text and line bigger.

It was blazing hot in 6th period. Students were tasked with using their textbook and the vocabulary from the desmos polygraph session yesterday to create a poster about a quadratic function.

Students labeled x and y intercepts and some understood the line of symmetry being x equals the x value of the vertex. I want to stress making that connection with better questions about noticing.

Class concluded with a gallery walk with each student getting a post it note to leave 2 stars and a wish. Some kids did not leave positive comments in the stars. It was a huge learning experience I thought too.

Video of the gallery walk:

Here are their posters: