## Thursday, May 26, 2016

### Day 163: Slope FAL & Pool Draining Task

This was my last day before my paternity leave. I am out Friday through the rest of the school year. The last estimation with myself and not the substitute was the value of a bowl of quarters. Students thought about 8 rolls were in there with each one valued at \$10 so it's worth about 80 dollars.

Students will be matching points, equations, and lines on a poster while I am gone. It's a MARS MAP lesson called Points, Slopes and Equations. I passed out the pre-assessment and it was clearly tough for students to engage with finding a missing coordinate of 2 points knowing the slope.

Basically students find missing side lengths using scale factor or proportions between corresponding sides (gotta emphasize that) of similar triangles. Then they figure out if 3 coordinate pairs are all on a straight line. They realized they needed to make slope triangles again and calculate the side lengths. Then they compared the slopes and realized they that one line segment did not have a slope of 3.

Then they find a missing y coordinate when given an x coordinate and another coordinate pair. Students had difficulty connecting writing an equation using the slope formula to undo it and solve for the missing variable.

I'm hoping students recall the vertical change / horizontal change when working with pairs of coordinates. They will need to reason about this when making matches on their posters. The substitute will have the answer key and dialogue highlighted.

Finally, students that didn't finish surveying classmates for their 2 questions for their 2 way frequency table did that. I think that next year I will go into more detail about relative frequency and the percentages within the table. Then when figuring out your hypothesis, you must use conditional frequency, where you make the sample space using one of the marginal frequencies outside the box.
 Here are the three different calculations students used to figure out how many hours it would take for the pool to drain.
In accelerated I used Kyle Pearce's Pool Draining task. As you can see above and below this paragraph, one student plotted the data on a scatterplot, drew a line of best fit, and not pictured, calculated the slope and wrote an equation. He got 57.4 hours. One student plotted after I showed him he could use the Table feature on the Desmos iPhone app. They then typed the linear regressions equation " y1 ~ mx1+b" to make a prediction.

I liked that students used linear and exponential models. I didn't get a picture of the exponential model, but students wrote an equation in y = a*b^x form with the average multiplier which I believe was around 0.975.

Here are the substitute lesson plan binders. I will be detailing what is in these for students and parents to see very soon.