## Day 141 – Cubes and Roots

Math 8 – The main goal for today was deliberate practice on calculating cubes and cube roots of perfect cubes. That part of the lesson was started with a comparison between the concept of a square and cube, then quickly going over a couple of worked examples, and then practice.

Before the cubes though, we did some voting on a Pythagorean problem. It was a direct copy of a homework problem. Lots of students didn’t do the three homework problems which sort of surprised me. I’m well aware of student attitudes towards homework and I personally think that most of the learning needs to happen in the classroom. But some practice is beneficial, particularly if the majority of students have a decent understanding of the topic.

Parts of today’s lesson were not that dissimilar to my physics classes yesterday, were cognitive science concepts such as distributed practice and deliberate practice come into play.

## Day 140 – Wave Interference

Physics 11 – The main goal for today was for students to investigate wave interference and standing waves. However, I started the class off with some voting questions using the wave equation. As you can see above, this was not time wasted. Everyone clued in on the second round of voting and could explain their mistakes.

I’m using distributed practice for the wave equation. Students have done a bit of practice over 3 days. I still haven’t given them a worksheet on it. Maybe we’ll get to this next class. By the time they are quizzed on it, they will have practiced this equation/idea over 3 classes with each class spaced over 2-4 days apart.

## Day 139 – Two Interesting Problems

Math 8Who Gets There Faster, Jim or Stan?

Today I worked on giving most of the instructions/prompts verbally. I thought it would be prudent to write down the numbers required though.  Maybe I should have tried it without the writing.

And a nice solution below…

While several groups clued in that distance/speed is time, lots of groups used equivalent ratios for their solution, which I was fine with.  The reasoning would be something like “Jim goes 9km in 2hrs, 13.5 km in 3hrs, and over 11km in 2.5 hours…”

The next problem was simply stated: I have a rectangular prism with side lengths 8, 9 and 12.  What is the furthest distance from one point to another?  One solution is shown below.  Once students were able to picture the vector they needed, many were able to find the correct answer. I liked this problem because it had a low floor – all groups were able to find some diagonals using the Pythagorean Theorem.

I was very proud of this lesson, both for what I had planned and on what students were doing. Virtually all the students were engaged and accountable. Even border kids who typically sit back a bit were interested in working on possible solutions.

## Day 138 – Slinkies

Physics 11 – Today students explored waves with Slinkies.  They looked a properties such as amplitude, frequency and speed, as well as generating both transverse and longitudinal waves.  Students played with making waves will recording video on their phones. This allowed me to speak with each group individually and check their understanding of the wave properties.  All in all it was a pretty relaxed class but our goals for the lesson were achieved.

## Day 137 – Getting it done

Math 8 – The picture above shows some students finishing their ladder project. Check out the curricular and core competencies on the back wall. This project was primarily about reflecting on process competencies.

Today the students also did a quiz on tilted squares. I wrapped up the tilted squares by asking the classes if anyone wondered why we studied it, if we already new the Pythagorean Theorem. A few students said they did, and I showed how a right triangle with side lengths a and b can be used in a tilted square to offer a proof for the Pythagorean Theorem. It turns out we can trust 2500 year old Greek mathematicians after all!

## Day 134 – Finishing Momentum

Physics 11 – We did a bit more practice with conservation of momentum today, along with some Peer Instruction voting.  To help with one question, I fired up the good old air track, shown in the video above.  The air-track is good but it’s limited by the carts that I have for it and the lack of a good spring plunger.

One of today’s voting questions is below.  I keep forgetting that this is pretty tricky for physics 11.  On the one hand the correct answer is intuitive.  You load something up with more mass it will slow down.  Using the concept of total momentum being conserved is harder though because students want to know what happens to the momentum of the rain falling.

I briefly talk about how momentum is a vector and we have to consider that momentum that are perpendicular do not add together as a single number.  I then quickly try to change the topic as this is waaaay above where we’re at with the topic.

## Day 133 – Math 8 is Back!

Math 8 – Today was my first day back with the grade 8’s, with my awesome student teacher, Jenny Yim, finishing last week.  She did a great job.

Today I wanted students to work with titled squares as an alternative to the Pythagorean theorem.  I framed it like this:  “I don’t trust 2500 year old Greek mathematicians.  Especially ones that throw their friends into a lake because they think that there is something called an irrational number.”

Once students are comfortable with using the titled squares I’ll show how it can be used as a proof for the Pythagorean theorem.