Tuesday, March 10, 2020

Lesson 12-8: The SSS Similarity Theorem (Day 128)

Today I subbed in a high school English class. Once again, it's in my old district, so it really is Day 128 at this school.

This is also my third visit to this school, and my second visit on an odd block day. My previous such visit is detailed in my February 11th post.

I won't do "A Day in the Life" today, but I will describe the two classes that meet today -- first period freshmen and fifth period seniors. As this regular teacher usually does on sub days, she assigns an article and asks students to highlight it and write Cornell notes/other responses.

My song for today is one that I haven't sung much since my days at the old charter school -- GCF. I like this song because its title is "GCF," the first line is "GCF," and the first three notes are -- you guessed it -- G, C, F. And so I've decided to restore it to my music rotation.

In case you're wondering whether there are excessive tardies the second day after the time change, one guy arrives nearly an hour late to first period. Unlike yesterday's school, today's school does have a Late Start on Mondays, and thus today is the first regular start day here after the start of DST.

Today is Tenday:

Resolution #10: We are not truly done until we have achieved excellence.

Today -- unlike my first two visits to this classroom -- the regular teacher decides to specify a strict cell phone policy in her lesson plan. This goes back to the fifth rule and the need to follow the habits of our 1955 heroes. As I wrote yesterday, just because it's Tenday, it doesn't mean that I should argue over the other rules.

And in fact, instead of arguing I decide to enforce this rule by writing some of the usual complaints about the no phone rule and posting them under the document camera -- I don't care if:

  • This makes me the meanest teacher/sub in the world. I'm enforcing it anyway.
  • You learn better when you listen to music on phones while you work. The generation of 1955 worked in silence, and they learned much more than us younger generations.
  • Everyone else is using a phone anyway. I'm listing the names of every single student with a phone out for your teacher, even if that's all of you.
But I do acknowledge the tenth rule as well, and add "We are not truly done until we have achieved excellence" to the bottom of the page.

From the time I display this to the class, I catch fifteen students with phones out -- this is just shy of half the class. I decide in advance to ask the names of the students who don't have their phones out -- since these are good students, they'll tell me their correct names. Any student (other than absent kids) whose name I don't get is transferred to the bad list. I inform the teacher that these 15 have their phones out in violation of her rules.

Also, after my February 11th visit, I decide to list names of students who don't do the work -- and don't stay for the Embedded Time tutorial to finish. This is also 15 students -- no, they aren't the same as the ones with phones out, but there's considerable overlap. (I actually end up writing 16 names because I get the names from the submitted papers, and one student didn't write a name on the paper.)

During the senior class, a counselor enters the room. She takes many students away in order to discuss their upcoming schedules at the local community college.

Of the twenty students in the class, all but four of them go with the counselor. And this is a problem that I've seen other teacher bloggers mention -- when a majority of students are gone, the other students assume that they're entitled to a free day on cell phones. It's almost impossible for me to enforce either a cell phone ban or a requirement to do any work.

Personally, I don't believe that students should get a free day because others are gone. This idea comes from the assumption that learning and doing work are bad, and so we should find any little excuse not to work. But I come from the assumption that learning is good -- if most of the students are gone, then this is an opportunity for me to learn more and get ahead.

In a math class, a teacher would often wish to avoid giving a new lesson on such days, since she'll only have to repeat it when the students return. In many cases, it often depends on the cell phone rules that are specific to each school or district. If a no phone rule is strictly enforced (including administrators visiting the classrooms to enforce said rule), then I'd have to give some sort of activity, free time on Chromebooks, or even sing songs the whole time -- whatever it takes to make sure that most remaining students put phones away.

Starting when there are 45 minutes left in the block (before Embedded Time), a few students trickle in after completing their college scheduling. If the class ever reached a majority of students in the room (11 out of 20), then I'd be justified in enforcing an assignment (even if it's just highlighting the article), but instead, the most in the class is exactly half (10 out of 20). The tenth student arrives with about 15 minutes left in the block.

Even so, I tell the returning students of the importance of highlighting and taking notes if they wish to be successful in the classes they signed up for. Many of these students have chosen classes for summer as well as fall, so they're just three months away from their first college class. I hope that for their next block on Thursday, they'll take what I say to heart.

I tell the regular teacher about the counselor visit and why I can't enforce her no phone rule. (I do tell her about the one girl who does read a book instead of her phone -- since she does follow the rule that I start to post before the counselor arrives, the teacher should know about her.) In the end, I don't mind not having to give her a list of seniors who have phones out or don't work, since she already has to deal with the fifteen freshmen when she gets back.

Oh, I haven't said what the topic of the current event article that the students (the freshmen, at least) must read an annotate. It's on something that's been all over the news lately, yet I haven't addressed on the blog until today -- the coronavirus.

Yes, I know that there have been other health scares in the recent past -- even since the year I first created this blog. But the coronavirus, unlike the others, has resulted in events being canceled left and right around the world. In the sports world, there's been talk about canceling the Summer Olympics -- unlike with annual events, I'd hate it if the Tokyo Games were no more, since we had to wait four years for them and we'll have to wait four more years for the next Games.

And the canceling has extended into the world of education. My alma mater, UCLA, has announced that starting tomorrow, there will be no in-person classes for a full month. This is tricky because UCLA is on the quarter system. This is the tenth week of the quarter, which means that next week should be finals. Those finals will be given online, as will the first two weeks of spring quarter. And all sporting events will be played in empty stadiums.

So far, only a few K-12 schools in California and the rest of this nation have closed. But as more and more events are canceled or postponed and venues are closed, I can't help but wonder whether either of my two districts will close as well.

This will be tricky for us subs. We don't get paid unless we work, so if schools close for an extended period of time, then I'll get no paycheck. If classes are taught online (just as they will be at UCLA), then there's no need for subs. (Recall that many of the classes I sub for have Google Classroom, so the infrastructure for online classes is already there.)

On the other hand, it's possible that instead of online classes, the missed time will be made up at the end of the year. This means that there will be work for subs. So I ask myself, would I really want to sub in July? At least I'd have a summer paycheck. (Ironically, a longer spring break and a shorter summer break reminds me of the school year under my Eleven Calendar Proposal. I'd love to see even a part of my calendar implemented, but not when it's caused by a pandemic!)

And of course, if the school year is extended through June and into July, what happens to the seniors who've signed up for summer college classes today? On the other hand, the coronavirus might not be fully contained by summer, resulting in the cancellation of summer classes anyway.

If classes are canceled at the district whose calendar is observed on this blog, then I might need to take some days off from posting too, in order to match the district. This is especially needed if the days are made up at the end of the year (so Day 180 needs to match our actual last day of school).

Lesson 12-8 of the U of Chicago text is called "The SSS Similarity Theorem." In the modern Third Edition of the U of Chicago text, the SSS Similarity Theorem appears in Lesson 12-6.


This is what I wrote last year about today's lesson:

Let's get to our Geometry lesson. We are now working on the AA~ and SSS~ theorems, which complete our study of similarity. There are several ways we can prove these at this point. We can use the original dilation proofs given in the U of Chicago text (Lessons 12-8 and 12-9), or we can use the one similarity theorem we already have (SAS~) plus the corresponding congruence theorems (ASA and SSS, respectively). In the past, I reversed Lessons 12-8 and 12-9 but this year I'm preserving the original order, so no, we can't use SAS~ to prove SSS~.

I don't need to make any changes to last year's lesson. Last year, I created and posted a new instruction worksheet based on the U of Chicago method.

No comments:

Post a Comment