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Two posts today, both kind of brief. They are about two aspects of my life. The first is my dad post, my Geometry teacher post is coming later today.

 

I have a 14 year old boy and an 8 year old girl. They are very different people. My son does not stress out about school in any visible way. While I hear parents in our community talking about their 8th graders spending hours on homework, I never see that. He is up an down in his school performance but he does not seem to judge himself by these exterior reports on his progress. Sometimes I wish he was just a little more concerned, but he’s doing just fine.

My girl cares deeply about these exterior reports on her performance. She wants her teacher to think highly of her, she wants to please us. I am charmed a bit by this but I also wish she was less stressed about these types of things. This morning she was unusually quiet and reserved before school. I thought it might be her allergies – she has pretty wicked seasonal allergies and spring has just exploded on us here – but that was only a small part of it. She was worried because in PE this morning she was due to take part of the annual fitness test. This made her super sad. She loves to run and play with her friends but she has already begun to identify some friends as ‘sporty’ friends and she does not see herself this way. She had tears in her eyes because of anxiety about a fitness test this morning. This brought tears to my eyes as I thought about other students crying in the morning because of an upcoming Geometry test (or an upcoming Biology test or whatever), I was shook up thinking about the impact on self-image, on feelings of self-worth, on just the general task of living through the day that I saw a glimpse of. I am so sad to think that I am seen as the cause of such stress in my students’ lives. I wish I had some insight into how to battle this for my daughter and for my students. I know with my daughter I can talk to her about how her time in running around a field has nothing to do with how much I love her or how I value her. I try, in an appropriate way, to let my students know that their grade on a paper is not an evaluation of them as people, just a snapshot of them as learners. I need to be more explicit with them more often as I was reminded this morning. I also need to be more explicit more often with my two lil Dardys at home.

Man, what a bummer of a way to start my day today. My next post will be about a much rosier ending to the day (at least the school portion of it.)

A brief post this morning. We are winding down in our AP Calculus BC class and the last topic of the year is a short unit on vectors and parametric equations. Many of my students buy a (slightly) different version of our text book so some do not have the vector chapter. I use a curriculum module from the AP site as the spine for our work through these ideas. I have to admit that I do not have a great amount of enthusiasm for this topic, at least at the level that we work with it. But on Wednesday we had a fun breakthrough in class. We were working on a fairly typical example of a parametrically defined function on the Cartesian plane and found its derivative. The kiddos asked for a picture so we graphed both the position and velocity vectors on Desmos. One of my students expressed disappointment that we did not see the order of the graphs so it was hard to move our eyes from one graph to the other to see how they related. I am more comfortable making GeoGebra jump through hoops so I moved on to GeoGebra and graphed both with sliders and leaving a trace on. The kids seemed to perk up a bit liking this visual better. Then one student asked me to change the velocity vector. Instead of having it rooted at the origin, he asked me to redefine it so that it was attached to the point, so that it would be a tangent vector. I made this adjustment (you can find my GeoGebra of it here) and the kids seemed so much more engaged immediately. The power of seeing the trace points move apart from each other combined with the direction and length of the velocity vector changing along really caught their attention. I want to tweak it a bit still, there was a request for adding the acceleration vector as well. At a time of year when energy is running low, it was a fun blast of energy and engagement here.

 

That’s all for now, just wanted to share something fun.

My school is looking to hire a new upper school math teacher beginning in the 2018 – 2019 academic year. I am in my eighth year here as chair of the upper school math department at Wyoming Seminary. We are located in northeastern PA right across the river from Wilkes-Barre. We are a preK through post-grad school on two separate campuses. The young ones – including my two children – are on our lower school campus located about three miles away from our upper school. My son, by the way, will be at our upper school next year. I am equally anxious and excited about this development. Our upper school is a 9 – post grad school that is a mix of day and boarding students. We have three dorms on campus and a number of faculty also live in campus housing. I lived in a boys’ dorm with my family for six years before moving into a campus home. We have a wonderfully diverse student body both in terms of where they come from – we have over twenty countries represented in our high school student body – and what their interests/talents are. We have nationally recognized athletes, we have top notch artists, we have stunning scholars. We have kids who LOVE math and are in Calculus as freshmen. We have kids who dread it and are in Algebra II as seniors. I firmly believe that all of these kids have meaningfully experiences and they grow as students while they are here. We are losing one of our valued members of the upper school faculty and I am sad to see him go. However, this is the time for me to look ahead and dream about what a new colleague can bring to our school. If you are reading this and are contemplating a change of scenery for next year, please reach out to me in the comments here or through twitter where I am @mrdardy or simply write to my work email. If you are reading this and you know someone who might be a great fit, pass this info along.

Our school’s website is https://www.wyomingseminary.org/

 

A non-mathy post for this morning. I feel like I need to clear my head out a bit here.

 

• Thanks to Meg Craig and the #Fitbos gang for helping to keep me motivated this past year. I set two goals for myself with my trusty fitbit flex. I wanted to accumulate an average of 30 minutes per day at an ‘active’ level. I compiled a total of 207.45 active hours. Last time I checked my multiplication, this exceeds my goal! I also set a goal of walking 2017 miles in 2017. I ended up at 2050.16. I am pretty pleased, but time is still working against me, despite this level of activity I am more achy and a bit paunchier than I was this time last year. Have to ramp it up to fight against Father Time.
• Thanks to connections that my wife has at her college I was able to score a gig as a DJ at the local college radio station. Almost every Thursday since June, I have had the great pleasure of spending two hours (from 4 – 6 PM ET on wrkc.kings.edu) playing pretty much whatever music amuses me on terrestrial radio. I have been compiling playlists over at Spotify where you can search me up as mrdardy. It has been one of the real joys of my life this past year.
• Mostly a consequence of my DJ gig, I have listened to more new music released in 2017 than any year since the birth of my son in 2003. It feels great to be reminded of the pleasure of discovering new music again. I still feel a bit overwhelmed when I read Best of lists at the end of the year, but there is a better chance of me knowing a number of items on these lists than I have had in years.
• At work we have had a couple of important changes. We moved to a new, rotating schedule. We have 7 periods, 5 of which meet each day. In a seven day cycle each class meets five times. Four of the meetings are 50 minute classes (every once in a while an assembly moves that back to 45 minutes) and meets once for a 90 minute block. This has been a great change in our daily lives.
• In our department we adopted a test correction policy where all students are allowed to earn back points by reflecting on their work. We ask them to submit corrections in the form of pointing out where/what went wrong in the problem’s work and then correcting said problem. I am super excited about this project and I see students being really thoughtful and attentive in submitting these corrections.
• My life at school has been a bit more hectic than I’d like, despite the change in schedule. I have five classes this year (more often than not, this has been my standard work load here) which is especially manageable in this new rotation. What has been tiring is that I have four different class preps. Keeping all these trains running in my mind, especially since my two Geometry classes are rarely ever aligned anymore, has been a tiring challenge. I think being 53 and having a 14 year old boy and an 8 year old girl in the house has an impact as well!
• I was able to attend TwitterMathCamp for the fourth summer in a row. As an added bonus, this past year did not conflict with my daughter’s birthday. Another bonus was that Atlanta is the home of an old high school buddy who was also my first college roommate. I had not seen him in years and had a lovely night with him and his family on a warm southern night, hours spent on his porch catching up was a delight.
• My time at TMC was followed by a trip to FLA that included a couple of nights catching up with friends in my old hometown of Gainesville. Had not been there in a few years.
• My school is a PK – PG school on two campuses. We live on the upper school campus, the lower school is about three miles away. My son is in 8th grade and he and his pals will be in my hallways in 8 months. Exciting and scary at the same time!
• My wife is nearing the end of her Master’s Degree program. It’s been fun listening to her talk about her school experiences. It has been ten years now since my course work last ended. I’m a bit jealous, I think.
• Off to face the new day, the new year, I guess, now…

 

Another quick post. We are in exam week here at my school. I have ALL sorts of thoughts about term exams and why we do them, but those are for another place rather than this public forum. I have written about our department’s decision to move toward a test correction policy. I am so so so optimistic about our exams this week. I really believe that we will see largely improved results because the students have been more actively involved with examining their tests and reflecting on what went right and wrong on their tests. They have been talking to each other and comparing ideas. They have been talking to their teachers about how to fix their problems solving approaches. Our department exams are mostly on the next to last day of exam week. This will work against our students as energy levels start running low. Despite this, I am hopeful that we will see a different level of engagement on these cumulative exams. I will report back either way in a week or two, but I feel good based on what I have seen in the past week of reviews in class and from watching and listening to kids in the hallway as they work together.

My Geometry classes have just finished a few days considering different translations on the Cartesian plane. We are working toward being comfortable with rotations (almost always around the origin), reflections (horizontal and vertical lines and the lines y = x and y = – x), and vector translations. Last week I had a particularly unsuccessful lesson where I tried to help my students discover a pattern for 90 degree rotations around the origin. I want to try and outline my thinking here and I would love love love any insight into why it did not go well and how I can improve this in the future, or even how to go back to cycle and revisit this with my current team of scholars.

So, my idea was this – try to pull together what we know about perpendicular slopes, our developing ideas of vectors as a physical object similar in nature to a line segment, and developing an intuition about the fact that a 90 degree rotation should result in a move of one quadrant in a certain direction. I asked for three coordinates from my students and drew a triangle. I asked them to predict where this triangle would end up after we moved it 90 degrees clockwise. Two of the coordinates given were in quadrant I and one was in quadrant IV. It seemed that my students were happy/comfortable with the idea that the two quadrant I points would live now in quadrant IV and that the quadrant IV point would move to quadrant III. This may have been a tepid agreement in retrospect.  Next, I focused our attention on one of the quadrant I coordinates and I drew a segment from the origin to that point. We talked about the slope of the segment, we compared this segment to a vector, we talked about the length of the segment. I then asked the students to imagine a wheel and I told them that when I think about rotations I think about a bicycle wheel. In my mind I saw this segment as a spoke and I thought about distance from the point to the center of the wheel. Here is one place where I know I failed my students. I did not explicitly stop at this point and discuss distance the way I could have/should have. I also have a handful of students who are still struggling terribly with the idea of calculating distance. We have been talking about it since day two, I have coached them to think about Pythagoras, we have practiced it repeatedly. The combination of squaring, of square roots, of subtraction in one piece of ‘the distance formula’ and addition in another piece of it, comfort with mental arithmetic, all of these factors are working against my students being unanimously comfortable with calculating distances. So, the next step in my plan was to ask them what they recalled about perpendicular slopes. They all should know this and most recalled it pretty quickly. We had a segment in front of us with a slope of 4/3 and my students quickly agreed, maybe passively maybe enthusiastically, that a segment perpendicular to this would have a slope of -3/4. So, the question at hand was now whether the fraction was in the form or -3 over +4 or in the form of +3 over -4. I was convinced in advance of this lesson that this string of conversations would be a positive path to take. I felt that the combination of recalling past slope ideas, looking at the physical Cartesian plane, tying in ideas of line equations, etc. would gel together to make a lasting learning experience. I was wrong. When I prodded them toward the conclusion that -3 over +4 was the conclusion we wanted I saw some uncomfortable faces. When I mentioned the idea of a spoke as a visual to hold on to, I saw blank faces at this point. I got a bit frustrated and asked for my students to describe to me what they were thinking of when I mentioned the word spoke. Nothing. I pulled up a google image of a bicycle wheel and asked them to tell me what the spoke was in the image. By this point their reluctance to engage in this conversation was building, my frustration was increasing, and any positive momentum in building this process was falling apart. My fault for showing my frustration. My fault for stacking up too many ideas at once, I think. When I spoke to my Geometry colleague she felt that adding on the layer of talking about perpendicular slopes was the tipping point of discomfort for my students. I trust her instincts on a number of levels in part due to her experience in teaching our Algebra I course. She knows these Algebra kiddos and knows not only what they know but how comfortable they are knowing it. So, at this point it was clear to me that this was slipping away. We limped to the end of the conversation. Most students were willing to agree that the point  (4,3) would end up in quadrant IV. They were split on whether it would land on (4,-3) or on (3,-4) and it honestly felt like many were mentally tossing coins to make this call. I showed them the conclusion on GeoGebra and we sort of ran out of time by this point.  We have since gone back and tried to reinforce the conclusion we reached and I think that most of my students can reliably answer this question, but I am completely uncomfortable with how we got there. I would love any insight/advice about how to best structure this info. You can certainly drop a comment her or over on twitter where I am @mrdardy

 

I mentioned in an earlier post that our school’s math department has adopted a new policy this year. After our spring workshop with Henri Picciotto (@hpicciotto) one of the decisions we arrived at was to allow (almost require) test corrections from students. The goal was to encourage and reward reflection and communication on the part of our students. When I wrote about it originally Brian Miller (@The MillerMath) told me he would hold me to my vow to report back on this. Here is round one’s report.

First, I should remind everyone reading this what our new policy statement is. Here is what my students read on their syllabus this year.

Beginning in the 2017 – 2018 academic year, the math department is adopting a policy of expecting test corrections on all in-class tests. The policy is described below.

• When grading tests initially each question will get one of three point assignments
  • Full credit for reasonable support work and correct answer.
  • Half-credit for minor mistakes as long as some reasoning is shown.
  • Zero credit (in very rare cases) when there is no reasonable support shown or if the question is simply left blank.
• When grading tests, I will not put comments, I will simply mark one of these three ways.
• You will be allowed to turn in corrections. Corrections will be on separate paper and will have written explanations of errors made in addition to the correct work and answer. This work is to be in the student’s words but can be the result of consultation/help. These corrections will always be due at the beginning of the second class meeting day after the assessment is returned. You will return your original test along with your correction notes. I will remind you of this every time I return a graded test to you.
• It is not required that you turn in test corrections.
• The student can earn up to half of the points they missed on each individual problem.
• This policy does not apply to quizzes, only to in-class tests.

The first class to have a test this year was my AP Calculus BC class. This class has sixteen students of the highest math caliber at our school. They had a test in class on Tuesday and on Tuesday night I marked those tests. On a number of occasions I had to restrain myself from circling something or writing a note to a student. I went through and only marked each question as a 0, a 5 or a 10. There were six questions, so I graded 96 questions overall. Only one 0 out of all these 96 questions. Thirty four questions earned half credit and the other sixty one questions earned full credit. Of those thirty four, most mistakes were minor and in the past they would certainly not have suffered a five point penalty, but in the past they would not have had the ability to earn back points and they would not have had the motivation to think clearly about what happened. Due to quirks in our rotating schedule, the second class day after yesterday is not until Monday. However, I have six of my students in my room after school yesterday working on corrections. All of them spoke to me about problems and three of them were working with each other. Four of the six students there completed their corrections and turned them in already. This feels like success. I know that it is early in the year and students have a little more energy right now. I know that this is my most motivated (by knowledge, by interest level, and by grades) group of my four different class preps I have this year so I will not expect quite this level of engagement right away. Oh yeah, two of the students there yesterday only missed points on one of the six questions. The could have happily taken their 92% and gone home to worry about other work instead. I expect that I will see another one or two folks today and then get a slew of corrections in on Monday. The initial grading was a little bit faster and I could get them their tests back right away. Looking at the corrections will take a little time, but this is time I want to take and it is encouraging the kids to think about what mistakes they have made and (hopefully) not make those same mistakes again. I’ll keep updating on this experiment.

 

Today I had three of my five classes meet and they all met before lunch. So, now, I am writing a blog post after lunch!

 

Here is the problem –

Doris enters a 100-mile long bike race. The first 50 miles are along slow dirt roads, while the second half of the race is on smooth roads. Assume that Doris is able to travel at a constant rate of speed on each surface.

1. If Doris’ speed on the first 50 miles of the race is 10 miles per hour, what must be her speed during the second half of the trip so that her average speed over the whole trip is 13 1/3 miles per hour?
2. If Doris’ speed on the first 50 miles is12.5 miles per hour, what must be her speed on the second half of the trip so that her average speed over the whole 100 miles is 25 miles per hour?

 

A fairly standard question and I admit I stole it directly from a text I use ( a pretty cool Differential Calculus book for my non-AP class) and I originally intended to just use it with my Calculus Honors class this morning. After the discussion with them, I decided it was worthy of the attention of my Geometry section and my Discrete Math class as well. It is kind of fascinating to me to think about the different receptions that the problem had in each class. In all three classes I asked them to think about the first question and wait until we discussed it before moving on. I KNEW what mistake was going to be made. There was no doubt in my mind that the answer to question 1 would be 16 2/3 and the students did not disappoint me. They focused on the information given and processed it in a logical way given their use of the word average when considering two measurements. What they did not focus on was time and it is logical that they did not because it is not explicitly mentioned in the problem at all. My hope going in with my Calc Honors kiddos was that this would be an object lesson in weighted averages. What it turned into in my other two classes was a bit of a primer in how to think through a word problem instead of just automatically applying some mathematical operation on a set of numbers in front of you. In each class after the initial incorrect solution was offered I presented the following question. “I have a 90 on my first test and I score 100 on my second. What is my average? Now, I have a 90 average after four tests and I score 100 on my fifth. Is my average the same in each situation?” I had hoped, overoptimistically, that this would prompt thought about time but in all three classes I ended up explicitly urging them to think about time. In Calculus Honors and in Discrete this led most (maybe all) students to a correct conclusion. Not so with my younger Geometry students who were still a bit wary of the problem. In fact, one student asked me if all of my questions were going to be like this. I need to be a little more careful about these last minute decisions to follow my muse and approach a problem. I need to be more thoughtful about how appropriate the question is for the audience at hand. I still believe that this is a meaningful question for my Geometry kiddos to wrestle with, but perhaps I would have served them better by not making this the opening question on the second day of school…

Both groups of older kids arrived at the correct conclusion to the second question and they were amused by the result. Only two days in but of the eight classes I have had, I’d say 7 were successful with one uncomfortable miss.

This post will make more sense if you have already read Joe Schwartz’s  (@JSchwarz10a) thoughtful blog post about two experiences he and I shared at TMC 17. I’ll wait here while you go read it.

 

 

Back? Good.

Alright, let me share a couple of reflections first. Joe is one of the many delightful folks whose acquaintance I would not have made if I had not taken the plunge into this online world of collaboration. He and I met in person in Minneapolis and had a really in depth conversation about parenting, especially with regard to tech use for children. His words have echoed in my ear this year and my wife and I took on the challenge of a smart phone for our 14 year old. My son does not know it but Joe is one of the reasons why I was able to sort out my protests and come to the decision to give him one. So, in addition to my life being improved by Joe’s friendship, my son’s life is improved by Joe’s wisdom.  Anyways… This summer I got to spend time with Joe again at meals (especially a LOVELY dinner at the oddly named Cowfish) and at a session run by David Butler (@DavidKButlerUofA) called 100 Factorial. As Joe wrote, he and I were in a group of four with Jasmine Walker (@jaz_math) and Mauren (Mo) Ferger (@Ferger314) We worked on a problem called skyscrapers (you can find a cool online link here ) and we were all full engaged. Now, I knew jasmine and Joe already and knew Joe was a primary teacher. This fact did not cross my mind during the time we were working on the problem, but it sounds like maybe it did for Joe based on his blog post. That evening about a dozen folks all descended on Cowfish for dinner and I was sitting near Joe and Jasmine. I won’t repeat the story of our conversation, Joe covered it well. What I do want to do is think out loud about my perception of the conversation and try to get into Joe’s head a little bit as well as getting into my own head. Early in the conversation I mentioned to Jasmine that I had the impression that she might be ‘mathier’ than I am. I tend to be a little self deprecating in this area, I have three degrees and they are all from College of Education. I have no formal math degree but I took a load of math classes in college and have taught a load of them in my 30 years of teaching. I know a few things and I am pretty quick at making connections, if I do say so myself. However, I also know that I am TOO quick to make certain conclusions and this caused some trouble in the Skyscraper game and I am also a bit too quick to throw in the towel if I don’t see at least some sort of pathway pretty quickly. I don’t need to know an answer right away but I do need to have some sense of where to find the answer to help me be persistent. As Jasmine and I were trying to ‘un’ one-up each other (Edmund Harriss (@Gelada) was sitting next to me and he joked that this was the opposite of a pissing contest) I was also wrestling with the question Joe had out on the table comparing the Exeter problem sets with the puzzle we played with that afternoon. Looking back, I fear that the banter with Jasmine about who was less ‘mathy’ may have been somewhat hurtful now that I see the feelings Joe laid out in his blog. If that is true, I am deeply sorry. What I DO remember distinctly about the conversation was that I described different initial reactions to the lovely problem sets and the creative puzzles that Prof Butler laid out. In the problem sets there is a reassuring (or distressing, I guess) sense that these are MATH problems. That there is some MATH technique or formula that will be needed to nudge me down the road to success. With the Skyscraper problem, it was clear to me that this was an exercise in LOGIC. MATH thinking strategies certainly are handy and helpful, but this problem did not yield to an algorithm (or if it does, I am not nearly clever enough to know it) but it did yield to persistence and communication. Joe talks about wanting to overcome some old residual fear or discomfort to go ‘play with the big kids’ on the Exeter problem sets. What I hope he recognizes is that he WAS playing on that stage, it was just in the cafeteria with Skyscrapers instead. I have had conversations around Exeter problem sets with students and with other teachers. They have been great conversations but they were certainly not more memorable than the feeling of diving in and and conquering the Skyscraper problem. Joe was an integral part of that problem-solving team and he caught a couple of my mistakes when I jumped to quick conclusions. We are all on a continuum of comfort and confidence in different problem solving scenarios and Joe’s thoughtful and honest blog post serves as an important reminder to me to try and be more aware of these feelings in others as a new school year begins.

Joe told us this summer that he has retired from his daily gig and is now doing a variety of consulting jobs. He talked about how some folks collect baseball stadiums over the years, visiting ballparks around the country. He talked about the idea of doing that with classroom visits now that he has a more open calendar. I would LOVE it if he carries through with this plan, it would be great to hear his perspective. I would welcome him to my school with open arms but I would also be slightly anxious and a bit nervous about it. Would I still seem like ‘one of the big kids’ if he saw me in action? This kind of anxiety, I think, is probably a good thing for me. It keeps me on my toes. I want to make sure that my students have a meaningful experience in my classroom and one of the ways I can do that better is to imagine that I was also crafting an experience for someone like Joe.

This school year I will be teaching four different courses – Geometry (2 sections), Discrete Math, Calculus Honors, AP Calculus BC. My Twitter feed is being bombed with first day plan posts, so I will jump in here as well. Sitting by a pool, so this I’ll not be lengthy.

Note that our first day has 25 minute classes and a long community gathering.

In Geometry I have started the past three years with a dramatic introduction to the handshake problem. It generates some fun guessing and conversations right off the bat. We are also able to revisit this problem in various forms during the year. I think it is a winning first day activity.

In our Calc Honors class I will take students out in the hallway with some wheels chairs. I will have a segment of hallway measured for length and we will have some races pushing these chairs down the hall. This, I hope, will generate some conversations about average speed tat we CAN calculate and all sorts of instantaneous information that we cannot. This should be a basis for distinguishing between secant and tangents over the first days/weeks of the course. Plus, it is fun to run down the hall!

In Discrete I am going to use a fantastic quote that I read this summer (you can find it here )  I think that this might generate some fun research and some fun conversations about magnitude.

In Calculus BC I want to start with a deep dive into a conversation about linearization and approximations. I have gathered some fun ideas on twitter about how this conversation can unfold. I hope it leads to quite a bit of noticing and wondering about accuracy and when/why that accuracy falls apart.