Day 38 – Concrete vs Abstract



Physics 11 – Students have a really hard time interpreting graphs like the one just above this text. Once they get good at the mechanics (procedure) of the interpretation, it can be done easily and quickly. My co-worker thinks students struggle because they don’t have a procedure or set of steps to do this type of task. I agree. We could give them a procedure, but what would be the point?

Today I quizzed my students on this learning objective again (graphing constant acceleration motion), using questions like the first photo above. This gives the students a concrete idea of what the motion is. It’s easier, and while I would hope that all my students can do the 2nd graphing task, I believe that it’s the first one that we really care about.

Day 37 – Defining a Strategy

Math 8 – We’ve moved onto estimating square roots, but today we did a small assessment of problem solving. Students have the above handout to define a strategy for problem solving that they’ve been using. We had mostly inadvertently started using the rubric from Mason’s Thinking Mathematically.

My handout/assessment can be found here.

The problem presented was a lot easier than painted cubes and many kids had success. I was also very clear that I wanted to see kids work through the strategy. Try some specific examples, attack the problem with a try, check to see if it works…

Day 36 – Working with Graphs

Physics 11 – We’ve started working with kinematic equations but before we got too deep into that, I had to go over graphing a bit more. Students really struggle with this topic. One reason for this could be that lots of the practice graphs I have them work with are really abstract in nature and don’t really describe any realistic motion.

It was time for Peer Instruction, and the above question and results were normal for the day. Vote #2 had a much higher correct answer rate.

Working with kinematic equations have brought forward two certainties in the physics classroom. Certainty #1 is shown below, and the question drives me crazy.


Certainty #2 is that students automatically go to equations to solve their problems.

I also saw people replacing variables in the work with an “x”. When asked about this, students said they are used to solving for x. So. Much. Work. To. Be. Done.

Day 35 – Curricular Competencies in Math

Math 8 – In our group work today I asked students to focus on two particular competencies:

  • I can ask others for explanations
  • I can contribute to a group task

I chose these competencies for two reasons. First, I know that some students were really struggling with the Painted Cubes problem and were backing out of their groups, trying to meld into the background. I’m trying to make sure that students are active in asking their peers for explanations. Secondly, some students will have a very hard time coming up with generalizations in problems like Painted Cubes. The idea is that even if a student cannot come up with the final solution, they’re is always something they can contribute. Maybe it’s an idea, a calculation, whatever.


Day 34 – Capacitors and Charge


Engineering Physics – As a re-introduction to dc circuits, I had students play with capacitors for a bit using some of my CASTLE materials. The highlight, as I expected, was when we discussed the conclusions from the above activity. About 1/2 of this class took enriched physics last year and wrote the AP Physics 1 exam. However, pretty much all students said that the charge originated in the battery. I then started to question their ideas and assumptions?

  • What is the middle of a capacitor? An insulator they tell me.
  • Can charge move through a capacitor? No, they tell me.

Hmmm…. lots of strained faces at this point. Then one student puts his hand up. “Are you saying that the battery pushes the charges into the capacitor and that the pressure in the capacitor pushes the charges on the other side, and that charges are everywhere in the wires?”

At this point I’m jumping up and down. “No! I didn’t say that! You did!”
Huge win for today.

Day 33 – Painted Cubes, High Fives

Math 8 – We continued with painted cubes today and several groups were able to start making generalizations. It was so great to see. There were lots of wins today. One student was so happy once she started to see that the cubes with 1 face painted increased with squares. She saw that if there was a 9x9x9 cube, the # of cubes with one face painted would be 7×7, and there would be 6 faces like that. Huge high-five!  Check out the whiteboard below.

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Day 32 – Pro D SBG Workshop


Today was our provincial professional day. I attended the science conference and gave a workshop on Standards Based Grading.

There were 32 attendees and a lot of interest. I think perhaps 6 people there were already using SBG in one form or another.

One thing that seemed contentious to people new to SBG is that I don’t really do unit tests.  I actually give goal-less problem tests, which I will hold up to any unit test in terms of drawing out the different topics of physics and how they fit together.  I could also give unit tests, but they would have to be scored separately outside of the SBG system and treated more like an in-class assignment/assessment. I’m ok with that except that I think neither the students nor myself will get anything out of it.

Another question raised was how does SBG help prepare students for university, because in university kids will get a couple of big tests and no re-tests. My answer to that is that university is so far different from high school that it’s irrelevant. A mid-term and final in high school has almost nothing in common with a university mid-term or final in terms of timing, size, scope and level of difficulty. My stance is that the best we can do is help students learn as much as they can in high school and take what they’ve learned about themselves to help them in university.

One regret I have about the workshop is that I didn’t collect a list of attendees and their email addresses. Collaboration is key for changing assessment practices and I feel bad that I didn’t help pool people’s contact information together.

My “professional” blog at has the SBG workshop materials and other blog posts on SBG, grading, etc.

Day 31 – Always, Sometimes, Never

Physics 11 – Students had two main tasks today. First of all they solved a couple of problems using graphical solutions. Next they had to answer the Always/Sometimes/Never question below.



I’ve used the Always/Sometimes/Never question before. Today most of the groups got the correct solution, although answering with examples can be difficult.

It will be interesting to see if students continue to use graphical solutions or if they will lean heavily on the equations.

Day 30 – Painted Cubes

Math 8 – Today the class started on the “Painted Cubes” problem. I figured this problem would be quite difficult for them, and I’m structuring the problem to focus on two things. First, I want students to use a problem solving strategy that helps them move from a specific case to a general case. Secondly, this problem is used to reinforce that squares, cubes, square roots and cube roots are not abstract ideas with weird symbols, but that they have physical meanings.

The students first have to understand what they know – the problem setup. Next, they have to be clear on what they’re looking for and what they want. To begin with this is the # of cubes that will have 3 faces painted, 2 faces painted, 1 face painted and 0 faces painted. What they’re doing today is solving a first specific example of this problem: a 3x3x3 cube. This is specialization. We’ll do a few more specializations, and then try a generalization.

In the top photo you can see a good example of the students checking their solution.  They knew they needed 27 cubes in total, and the solution in the bottom right corner didn’t allow them to have a cube with 0 faces painted.

The other photos show how some groups are trying to specialize with a 4x4x4 cube, and how to record their information in a way that makes sense.

Day 29 – Launcher Testing


Engineering Physics – At times it was a bit like pulling teeth, but today we finally got to test most of the Cart Launchers. The carts are difficult to design, much more complicated than a mousetrap cart because they need to trigger a launcher in mid-run. Not surprisingly, so far the best performing cart has the simplest design.