Friday, May 19, 2017

Lesson 15-8: The Isoperimetric Inequality (Day 158)

This is what Theoni Pappas writes on page 139 of her Magic of Mathematics:

"Much study was generated in the 1800's on the mathematics of ocean waves. Observations at sea and in controlled laboratory experiments helped scientists arrive at interesting conclusions."

This post fulfills my monthly posting requirement for Tina Cardone's "Day in the Life" project. My monthly posting date is the 18th, but I'm doing a "Day in the Life" for the 19th instead. As it turns out, the events of the 19th are much more significant than the happenings of the 18th.

9:00 -- Substitute teaching is nice, but I have a math credential. So I need to be looking for positions as a regular math teacher. Keep this in mind as you read about my day. At 9:00, I head on out to the first of two interviews scheduled for the day.

11:00 -- I arrive at my first interview. It's actually for a substitute position, believe it or not. You see, in case I don't get the full-time position, I want something to fall back on. I'd already returned to my old district to sub, but I'd rather have two subbing positions to ensure that I have regular work.

I was referred to this position by the dean at my old school, who informed me about a woman who operates an independent contracting service for subs to work at charter schools. I'm supposed to meet her at one of her charter schools at 11:00. But unfortunately, like my old school, this charter has a sister school, and the lady I'm to meet is stuck in traffic coming in from the sister school.

12:00 -- My interviewer arrives. She tells me that it's possible for me to receive calls for subbing this year even though the year is almost up. Still, I inform her that I'm mainly interested in subbing for next year, since I want to continue my search for full-time work.

12:45 -- My second interview isn't until 4:30. I have the luxury of time, so I purchase a fast-food lunch for myself. I don't want to drive all the way home. But on the way from my first interview to my second just happens to be my old school. It's lunchtime there, so I decide to eat my lunch in my car right outside the school. I definitely miss my old students, but just as on Pi Day, I don't want to be a distraction. So I eat in the car and hope to watch the students on the playground.

12:50 -- Well, that doesn't take long. One of my former seventh grade boys spots my car all the way from the playground. Then a group of seventh grade girls run towards the fence separating the playground from the street. I acknowledge the group with a wave and then drive off. As I leave, I spot my successor teacher walking towards her car with the English teacher. Neither of them see me as I pull away.

By the way, today is the final day of testing at my old school. If you want, you can consider this to double as the "Day in the Life" post for the special day "State testing day."

2:00 -- I stop off to buy some materials for my interview. As it turns out, this interview for a regular teaching position also has a demo lesson component. I am to create a demo lesson on solving systems of equations by elimination.

Earlier this week, I was reading one of my favorite math teacher blogs, Sarah Carter. She's just started a new series of posts called Monday Must Reads. Here's a link to last Monday's post:

http://mathequalslove.blogspot.com/2017/05/monday-must-reads-volume-3.html

Carter writes:

Christie Bradshaw recently blogged about the resources she created for teaching systems of equations.  I included her tweet about creating a dry erase template for the elimination method in Volume 2 of Monday Must Reads, so I wanted to give everyone a heads-up that she is sharing the file for free (plus several other files) on her blog!

And I said to myself, hey, look at this! Here's a link to a lesson on solving systems of equations, which is the exact topic that I'm about to teach in the demo lesson! That's something I can take to the bank right away!

By this point I've already purchased the dry-erase packets and created a template based on Christie Bradshaw's lesson, so all I need are markers. I buy six markers with built-in erasers.

2:30 -- I head on up to the interview, stopping to purchase gas on the way.

4:00 -- I arrive at the school, but it takes me a while to figure out where to park.

4:30 -- The demo lesson begins. There are seven students who actually choose to stay after school on a Friday to accommodate the lesson. Oops -- I only have six markers, but fortunately there are a few markers in the classroom. I do have more than enough templates, fortunately.

I actually come up with the systems to solve from the Illinois State text. As it turns out, most of these are set up to eliminate y first, so my template is set up to eliminate y. Notice that Bradshaw's original template is set up to eliminate x first.

4:50 -- After the demo lesson the interview begins. The students are part of the panel, and they ask me questions such as "Is this your favorite method?" and "What is your homework like?"

5:10 -- The interview ends. I drive home after a long day.

According to one of the review questions, "if we finish the next lesson, our class will have done every lesson in the book." Note that Lesson 15-8 is the penultimate lesson of the U of Chicago text.



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