135-136 Desmos Build Day #2

Because of AP testing, the other PreCalculus class got an opportunity to make some Desmos creations in the Innovations Lab.


133-134 Time to Restock

Because of all the whiteboarding, our erasers were getting a bit … worn.

Replacement time.



131-132 Desmos Design Day

18 of the 24 precalc students had a field trip. The rest of them designed stuff in Desmos and then we went to the innovation lab and lasered and printed their designs. I showed how to create this coaster design for about 5 minutes, and then let them play.


Used this workflow to get their designs ready to print. The poster design was rendered in high definition with fragmentarium (but originally designed in desmos).


129-130 “Superhero” Powers

This student is using their “superhero” powers to expand (x+h)^3 (pascals triangle and binomial expansion). Fancy right?


127-128 Limits: A little over a lot

One of the algebra 2 teachers uses this picture to explain what happens when you divide a little number by a big number and vice versa. Cool to see that it stuck. The students were using it to determine limits to +/- infinity.

Here’s the “Michael limit test” for limits to infinity. Plugs in 100 for x. Useful idea!


125-126 Limits with Desmos

Introduced Limits with a couple of Desmos Activities:

Worked quite well.


123-124 “Course” Corrections

Have you ever tried to swim in a lap pool with your eyes closed? How long were you able to go without hitting a lane divider? I can get about 5 or 6 strokes in before I hit and need to correct my direction. I’ve done some triathlons, and one of the hardest parts of racing is swimming in a straight line. You can train all you’d like on lanes, looking down at a lane marker to go straight, but swimming in open water is a different challenge. The thing that worked best for me was to take some number of strokes, say 10, and then take a look to make sure you’re pointing in the right direction. As your muscles get more tired you tend to wander in different directions.

I’ve been asking my students for quarterly feedback for 4 or 5 years, and I’d put it in the top three changes that I’ve made that have most affected my teaching. I use the feedback to keep me honest. It’s hard to open up to anonymous feedback from teenagers, you think the worst is going to happen. But I’ve found that not only do they give marvelous feedback (“course” correction, do you see what I did there), but they tend to appreciate the addition of another data point that you give a damn, and that their input matters to you. There is so much good stuff that they have to say, and if you provide them time, space, and importantly, optional anonymity; they will hand you pure gold. It doesn’t have to be a long feedback form, my quarterly feedback form is only 6 questions:

Here are some quotes from this past feedback session, for some context, these are Juniors and Seniors in advanced math classes.

I love how in depth they think about how they learn best, and they definitely don’t all agree on their favorite methods. I love how they give me constructive feedback and compliments in the same response. I also deeply appreciate their pushback on thing that we need to work on as a class. And this isn’t some royal “we” going on here, they often see changes that they themselves can make to improve their learning (not that they always take themselves up on their own advice!)

An important part of this feedback cycle is to acknowledge their responses publicly. I like to try and get the gist of each question and write down my takeaways. I also think it’s useful to take a comment that I disagree with and explain my thinking. For example, there is a group of students who would rather I was more flexible with my reassessment policy. I explain to them that I wish I had a time turner because then I could provide each and every student as many opportunities as they needed to prove their knowledge on a topic.

I hope you can find a time to try something similar in your classes. It’s hard to not focus on a negative bit of feedback, but I’ve found that I’ve gotten ever so slightly better at seeing the big picture. You gotta bang into some lane dividers to keep your path.


121-122 Precalc Projects

Now that I’ve gotten more adept at the laser cutter and 3D printer, it’s been fun to produce some visuals for the students and their projects. Some help them visualize a complicated scenario, for example breaking a truncated icosahedron into pyramids to measure it surface area and volume. Some help them verify calculations like looking at the math behind logarithmic spirals and nautilus shells. Some are just motivating to play with and figure out the underlying math (Escher’s Circle Limit Puzzle). It’s been a ball having them all working independently and just trying to help through sticking points or provide some guidance for direction of study. I’ve also provided some programming and excel work to help visualize tough problems. We live in a great time, technology truly is helping these students solve problems that they want to solve.


119-120 Favorite Time of Year!!!!

The Precalculus students are starting their exploration! More information here.

Here are a bunch of the topics that they’re researching!!




117-118 Dot Product Property “Proof”

A homework example asked the student to find the square of the size of a vector and then find the dot product of the vector. Same answer. Weird. Student asked, is this always true? Why, LOVELY QUESTION!