Day 28: Solving CA Problems with Graphs

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Physics 11 I decided to have the kids jump right into solving problems with little guidance from me.  8 questions and 8 groups later, we were off to the races.  I was a bit surprised to see most groups first try to hunt and find equations to work with.  Lots of kids were pulling out their agendas, where they had seen a page with physics formulas on it.  I pretty much had to stop the work and point out that all we’ve used in the past few weeks are graphs, and that graphs would be the smart path forward for this task.

In groups the students were pretty good with negotiating with slope and velocities.  Most groups needed some prodding to recall that the area under the curve on a velocity-time graph was displacement.  The 2nd photo above was a good example of students working through the issue of displacement.  The bottom photo, the group needed more prompting to get through their problem.  They were getting stuck with mixing up pythagorean theorem and the meaning of slope.  This was a good example of how changing the context of the question (instead of asking a graphing question, they were asked a kinematics word problem) can easily change how students apply their understanding.

The top photo shows how a few groups were approaching displacement.  When working with constant velocity, the area under the graph is calculated by finding the area of the rectangle.  When given increasing velocity, they no longer had a rectangle to work with.  Instead, they decided to break the triangle into smaller rectangular regions. I like seeing things like this because it shows problem solving skills, and I get to say that they are doing the same thing as calculus.  The group in the top photo initially started doing the problem by applying a formula, but when they got to displacement, they weren’t sure what to do.  So they decided to make a graph to see what they could find out.

Next day they will have a quiz, so I’m not sure how much time we’ll have to expand on problem solving.  I may just derive some formulas from their graphs, and model how I would expect a graph to be annotated as a means for demonstrating understanding.

Day 27: Diffusion and Osmosis


Science 8 I gave these graphics to the students and had them make observations. I didn’t know it at the time, but the work that we put in at the beginning of the year with observations is really paying off. I was able to randomly go around the room and get good responses from almost all of the students. The diffusion example was recognized as being very similar to our food colouring lab, and the kids were able to see how osmosis was different (sugar particles couldn’t go through the membrane but the water could). The class still has to work through the specifics, especially in terms of concentration. I think next class I will use some Peer Instruction for formative assessment and checking for understanding.

Day 26: Working with CA Graphs


Physics 11 Today was spent working through graphs of objects moving with constant acceleration.  The majority of students got it ok, but almost everyone needed a few corrections or challenges.  A few students were starting to hit the wall on clearly understanding how these graphical descriptions fit together.

The students that had problems reminded me a lot of what I saw when teaching Math 10 last year.  They would show understanding but then a few minutes later would get stuck. And I mean really stuck.  I think this is a perfect example of cognitive overload.  Cognitive Load Theory (CLT) informs us that when a person’s cognition is taxed to its limit, the brain is no longer able to transfer knowledge from short term memory to long term memory (that’s my lay person’s explanation). I believe this is what I see with a few students in physics.

I believe that the best way to deal with these situations is to first try and recognize that it’s happening.  If a kid is getting stuck, telling them to go home and do more practice probably won’t help a ton. In the particular situation of CA graphs, I offered three strategies for students to use to help them work through confusion.

Strategy 1

I encouraged them to break each part of the position-time graph into separate sections.  For each section, they then write in words what the object is doing.  All the kids can do this (moves forward, moves backwards, moves faster, etc).  For each section, I then have them explain how the motion affects velocity (constant, getting faster, getting slower, etc).  Now they graph what they wrote down for velocity

The above may seem formulaic, and it is.  However, it is a series of steps that doesn’t dance around conceptual understanding.  It’s a way for students to verbalize their guide to the motion.

Strategy 2

The next strategy I suggested was to take the position-time graph and sketch tangents on it.  As long as the student understands the correlation between slope of the tangent line and velocity, they can build the velocity-time graph. Again, the strategy still depends on a conceptual understanding and is not just a series of steps.

Strategy 3

The third strategy I proposed was… oh who am I kidding. I can’t remember what the third strategy was.  It seemed like a good idea at the time. If I remember it later I’ll update this post.

Day 25: Using Smarter Science


Science 8. Today we worked through an experiment using the Smarter Science framework. I could see its usefulness, as there were several places where students were tripping up in the process. In previous classes we talked through the experiment while I wrote things down on my tablet. Today’s class I tried using the post-it notes as shown in the photo above. I think that for grade 8’s, the overhead projector with both me and students writing at the same time was better. Using post-it notes left the kids doing nothing for a bit… They would just be watching me move the notes. It caused them to be too distracted.

What was really interesting to me was that a few students ended up with test procedures that were trying to test two variables at once. I’m looking forward to doing this again soon.

Day 24: Graphing Constant Acceleration


Physics 11 Today we finally graphed data from our constant acceleration lab. There were several hurdles to overcome, most notably the kids getting their head around what a tangent line is.  We finally had some really good discussion with the whiteboards, with students really challenging each other.

Some common pre-conceptions encountered:

  • the velocity time graph should have horizontal lines (like before)
  • points on the graph should be connected with a line
  • a faster starting push on the object should make the v-t graph steeper because it’s going faster

I’m not sure yet how I will deal with the quadratic relationship. If I go over curve straightening, it will certainly be a bit hand-wavy.

Day 23: Professional Development Day

[Science 8, Science 9, Physics 11]  Friday was a PRO-D for everyone in BC. I attended the BC Science Teachers Association conference. The keynote speaker was a forensic etymologist from SFU. She spoke about her studies/profession. While I found it mildly interesting, I have no idea why that was the keynote. I think I could have spent an hour doing a keynote on how Course Planning is a lot like Quality Assurance programs. Or something. Anything, really.

I had signed up for two sessions with the Smarter Science people. Smarter Science is a framework for conducting inquiry in the science classroom, and the gradual release of responsibility that goes with inquiry. I wasn’t sure how much I’d get out of it, as I have been trying to incorporate inquiry for a few years now. However, it turns out that the morning session was just what I needed. We worked through their framework by using an example. The example was eerily similar to an inquiry session I did with my grade 8 students (dissolving starch packing peanuts). The difference is that Smarter Science provides a concrete framework around the work. We had done the same steps, but each step wouldn’t have been so clear to my students. Our inquiry was more like living in the moment, whereas if I had the framework in place the students would have had a better vehicle for reflecting on the work that they had done.

I would encourage all science teachers to take a look at the Smarter Science website:

Day 22: Quiz Day

My physics 11 students had their 2nd quiz today, and then they continued along with their constant acceleration labs. There’s not a lot to report, quizzing still seems to take up a lot of class time. I guess that’s just the way things go. I could pressure the students to work faster but that’s not really the point. They’re just consolidating their learning and doing everything correct AND fast doesn’t seem to be the best expectation. That’s all I have for Day 22…

Day 21: Atomic Story Cartoons

In Science 9, I had students read through their textbooks about the evolution of Atomic Theory. They each then had the option of completing textbook questions, workbook questions, or creating a Concept Map. Once I checked over their work, they moved on to an assignment/learning objective that would be assessed. The idea was for kids to complete a story using the characters Dalton, Thompson, Rutherford and Bohr. Most kids opted to do a cartoon, and the one above was done quite well.

I was pretty surprised by the cartoons I received. Most seemed to have missed the main points of Atomic Theory. While all the kids could answer questions about each theory/model, when the students were left to create their own dialogue they could not identify the significance of the models. For example, many kids said that Bohr’s idea was that the electrons were outside and not orbiting. Others weren’t able to communicate the idea that there was a steady progression of ideas.

Day 20: Periodic Table


In science 9 I asked the class to create a periodic table based on several fake elements. The idea was that students would get a hands on idea of how a table can be designed in a way that makes its information easily categorized. However, I don’t think I gave the classes enough scaffolding.

Almost every group started with a naive design solely based on atomic mass. With feedback I got most groups to develop a better, more intricate, design. A few groups were able to produce three levels of categories. Unfortunately some groups only managed to incorporate an artistic look to go with their sorting by atomic mass. I think this activity would be better as an assessment piece after studying Mendeleev’s periodic table.

Day 19: Constant Acceleration


We got to use our textbooks again today. Not only that but we also managed to incorporate the use of some biology books. Physics truly is the underlying science.

The students managed to collect what looked like decent data and plot their x vs t graphs. Next day I will have them find tangents and create a V vs t graph. I suppose we’ll even try some curve straightening to develop a relationship between position and time.