# Working on the Holiday

So, one of the oddities about teaching at an independent school is that days off that are taken fro granted most places are seen as prime days for campus visits here. So, we were in session today. No need to feel sad about this though as we have plenty of vacation time as well. Just another Monday.

But…it wasn’t. It was a terrific teaching day and I want to make sure that I make note of it even if only for my own pleasure.

Bells Three and Six – AP Statistics. My senior heavy Stats class did not come back from winter break with much of a sense of urgency. I did not want to just launch right into a new chapter on the heels of the disappointing chapter test we had on Friday. My Computer Science colleague had recently shared with me information about Sicherman Dice which are two six-sided dice that are not standard dice but their sum has the same probability distribution as the sum of two standard dice. I presented my students with a  challenge. Describe two six-sided dice that replicate the probability distribution of two standard die. No other directions really. I have a rudimentary handout I gave them and you can grab it here. I fielded questions as they chatted about this problem with their neighbors. Can the die have negative numbers? Can the die have fractions? Can the die have zero? I kept replying in the reluctantly affirmative and checked on their progress. Most of them had a pretty logical attack where they would transform one standard die in a certain direction, say subtract two from every face and then transform the other one in the opposite direction. Not very sophisticated, but it was nice algebraic logic. One student was working on fractions trying to balance combinations of 1/3 and 2/3 so that she would always get integer answers. Overall, it was the most focused energy from this group that I have seen in two weeks. I hope that this is an omen for our next unit. They were pretty surprised by the reveal and I am curious, in retrospect, that they never asked if any die could have repeated values as this is necessary for the Sicherman Dice to work their magic.

Bell Seven – AP Calculus BC

We’re just getting ready to start exploring the magic of Taylor Series. We took baby steps today reminding ourselves of the language of arithmetic and geometric sequences and series. I always think that this material is such fun to untangle. Tomorrow we’ll play with GeoGebra and I will try to tease out of them the key ideas about how to make a polygon behave like the sine function. Nothing much else to report here.

Tomorrow three of my four classes will be taking unit tests. I have always devoted the class day before a test to review. Over the past 5 – 7 years I have become more and more insistent that a review day should be a day where I am here to answer some questions that students come to class with and to help facilitate some meaningful conversation between my students. What many students seem to believe is that review day before a test is simply a time for me to tell them exactly what will be on the test. I always come to class on these days with some prepared questions in my back pocket and I always dream that those questions will stay there. That is not often the case, and it certainly was not the case today.

My Geometry class, the one I’ve been SO proud of recently, was in pretty good shape. We looked at our last HW together, they had some good questions about that but they could not really generate too many meaningful questions of their own. I displayed the review questions I had prepared and they perked up and were terrific in joining in the conversation. I just came away wishing that the class had been more about them and what was on their mind. In retrospect, perhaps it was exactly about what was on their mind. They are concerned about what I am interested in right now so that they can glean some important clues about preparing for tomorrow’s test. Sigh…

My two AP Statistics classes are in a different place emotionally than my Geometry class is. They are almost all seniors and the energy level that they brought back from winter break is distinctly different than the energy level I see in my Geometry students. I gave them class time yesterday to work on their own or with their neighbor on the review exercises at the end of their most recent chapter and my observation is that there were relatively small pockets of productive conversations. However, there were also quite a few incidents of aimless chatter, obsessive checking of their phones, silly debates, and general non-statistical conversations.

So, I feel that I am asking myself the same question I asked myself on these pages just a couple of days ago. How can I be less helpful in the standard sort of hand-holding way that my students want me to be while actually being helpful to them in modeling smart behavior about how to work, how to be metacognitive, how to be reflective, and how to be more self-aware. Trying to recall who I was when I was in high school is probably not the best exercise in answering these questions. I was a different person then than I am now. I am remembering through a distinctly tinted memory lens and I am not teaching four classes of teenage Mr. Dardys.

Gotta keep thinking and keep pushing.

# The Perils of Being ‘Less Helpful’

i am guessing that most people who will read this are familiar with Dan Meyer’s TED Talk. When I first saw this it crystallized some ideas that had been festering for awhile. It also articulated some thoughts about my evolving practice as a classroom teacher. I have shared this video with my department colleagues and have also shared it in class with students. As I have mentioned before, most of the teaching I have been doing at my current school (I arrived here in 2010) has been with AP Students. They are pretty well equipped to deal with the sense that I am being ‘less helpful’ with them. Of course, I want my students to feel supported, but I also want them to be pretty self-sufficient. We have a feature in our schedule where school ends after eight periods ( we call them Bells ) and every teacher is expected to be in their room for Bell 9 which is a time for students to come for extra help. We call it conferencing here. This background sets up my post for the night.

Any wisdom out there for me?

# Success!

I have had a very active blogging week thinking about (and writing about) my Geometry class. I have three preparations this year, AP Statistics, AP Calculus BC, and Geometry. I’m not proud of it, but I know that my attention to each class varies at different times of the year. Iy’s not a simple matter of 33 1/3 % of my planning energy being spent on one class at any time. Do many of you go through this as well? By the way, how many preps do most folks have?

So, this morning I felt confident as my cherubs asked their last few questions before the quiz and the results are in. I have 12 students in this class and 4 of them earned perfect scores with another 4 earning an A on the quiz. Their class average was 93%!!! I’m thrilled by this. I think that this is due to a number of factors.

• In general, my students have had more energy this week in January than they did in the few weeks leading up to our winter break.
• I believe that the HW strategy has made a positive difference.
• I believe that the extensive use of GeoGebra in class is finally spreading to the home. I have overheard a number of students this week make reference to looking at GeoGebra while doing their HW this week. I am a firm believer in the power of these graphing programs and, for my Geometry students at least, I think that this is the best of the bunch.
• I worked hard during break planning out this unit for me and for my Geometry team of two terrific colleagues. This thoughtfulness has paid off.

Oh yeah, one final thought. As a long-time Calculus teacher I have a strong preference for lines in the point-slope format. Every one of my students presented at least one of their line answers in this format.  Woo-hoo!!!

# On a Roll

Man, my Geometry students are on a roll right now. Today we went through our same new HW procedure again. I was quiet for the first 5 – 8 minutes of our 40 minute class while my students shared their HW with each other. They were asking each other good questions and catching each other’s mistakes. They are still a little shaky at times on their line equation writing skills and their line intersection skills, but the mistakes they are making are much more of the arithmetic and detail type rather than broad conceptual mistakes about what to do.

I should have dwelled a little more on my second stats class yesterday. I was really pleased with the three different formulas that those four groups generated. I was especially intrigued by the group that decided that the minimum number in their sample plus the maximum number in their sample should be a good estimator for the true max in the population. I discussed this idea with my morning stats class and we had a pretty vigorous debate over how appropriate this was. Playing with our TI and drawing random samples of 5 from a group of 342 (kind of like the German Tank problem!) convinced them that this technique actually turns out to be pretty accurate.

It’s easy to actively blog when it’s fun to relate what’s happening in class. I hope I can keep up a reasonable pace, if not daily, for the year.

# Beginning New Habits AND a Fun Activity

This morning in Geometry I started by not talking for the first five minutes while my students shared their HW with each other. They talked about their answers, they puzzled over why/where they differed and they talked about using GeoGebra on their own to explore the intersection of perpendicular bisectors of triangles. I was SO delighted I almost wanted to call the rest of the day off.  I did not, though and I’m glad I stuck it out.

We looked together at GeoGebra, reviewed (again) how to find the intersection of lines, we let GeoGebra confirm that we were right. We remembered from yesterday that these lines coincide on the hypotenuse for a right triangle, in the interior for an acute triangle, and outside of an obtuse triangle. After playing with another GeoGebra sketch we all agreed that this behavior made this point of coincidence a pretty poor candidate for the center of a triangle. I pointed out that one of our students had suggested – on his way out of class yesterday – that we should concentrate on vertices rather than midpoints of sides. Again, we let GeoGebra take over and looked at a compromise by constructing a line through a vertex AND through the midpoint of a side. I named this for them as the median. I also displayed that these medians seem to ALWAYS intersect in the interior of a triangle and I named this point for them as the centroid. We all agreed that this name was ‘center-y’ enough. As time ran out, at the suggestion of another student, we asked GeoGebra to construct angle bisectors. It does so, but draws an exterior line as well. They did not complain when I erased them, but I want to examine what is really happening there. It felt a little too much like I was waving away a distraction. We saw that these angle bisectors intersect in the interior as well – setting up a great debate for tomorrow about which center is the center-est. Just thrilled with how they hung together during the intro time and during the quick GeoGebra exploring. Need to commit to both HW review time tomorrow and to revisiting the blur of activity on GeoGebra. I am planning on a lab day for Thursday so that they can manipulate these ideas themselves.

In my AP Stats I tried out the German Tank problem using resources found here at the Stats Monkey site. My two classes dealt with this in pretty different ways. My smaller class (12 students today) worked in 3 groups of four. I made a mistake in responding to one of the first ideas I heard. One group decided to invoke the empirical rule and guessed that the # of tanks was their sample mean plus three standard deviations. I responded positively to them but this simply steered the other two groups into following this lead. In my other class I was smarter and quieter. Here I had four groups of four. One group invoked the empirical rule but they also pooled their three samples together. One group used the inverse normal function on their calculator seeking a point where the area was 0.999. One group added their sample minimum to their sample maximum guessing that they should be (roughly) equidistant from the extremes. The final group doubled their median guessing it should be halfway to the max. I was thrilled with the level of discussion and the variety of responses. A great step forward from yesterday’s disappointment where they largely ignored my Radiolab assignment.

I’ll count this day in the victory column for sure.