## Day 90 – Popsicle Bridge

Engineering Physics 12 – Students started working gluing together their first popsicle bridge.  They were given specific plans and instructions on their build and I handed out three different truss designs: Warren, Pratt and Howe.

The idea here is that they will have some practice in clamping and properly assembling a bridge.  The next step after this will be for them to use their knowledge of truss/joint analysis to design and build their own bridge for the TRU bridge contest.

## Day 89 – Problem Solving Assessment and Paddle Design

Math 8 – Today was very busy. First I had students complete an assessment on problem solving.  I asked kids to complete their own individual work for 10 minutes and then I then I put them into random groups and had them work on it together. Finally they were asked to reflect on the process.

The assessment had some good and bad. On the bad side, the problem was probably too difficult. Many groups did not get very far.  The easiest solution was to use trial and error, and a couple of students solved it by writing out an equation.  Some students/groups started with trial and error and then identified a pattern that helped them.

Because of our previous fraction problem, lots of kids got trapped into trying to work backwards, which really isn’t the way forward. I think this activity would be really good if a better problem was given: something with a lower floor but high ceiling.

The students also were given the start of an on-going project that we’ll work on.  They are using measurement and proportional reasoning to size their personal Greenland paddle.  Later in the year we will take these measurements and model them in Onshape and 3D print them.

To properly complete the Greenland paddle, complete design schematics are needed.

## Day 88 – Lab Practicum

Physics 11 – I divided the class into  random groups and each group was given a bucket with three masses, two Newton scales, and a wooden block.  Their task is to determine the coefficient of friction between the floor and the wooden block.

Most groups were content to take one measurement and use that to calculate the coefficient. I stepped in a bit and suggested that they get more data. I did this by asking them what their independent and dependent variables could be, which helped.  Some students even showed understanding of how they could use a graph to help determine the coefficient, while others were happy to average a range of numbers.

Overall the activity went ok.  They were asked to hand in a good lab report, which will then be graded. They previously handed in a lab report which I gave them feedback on. Hopefully they will take my feedback and use it to do a good job on this one.

## Day 87 – Robotics Club

Robotics Club – We’ve been getting consistent turn out for the robotics club, which is nice.  There has been more progress with having the same kids show up every week, so hopefully we can enter some local competitions in the upcoming weeks. Students seem agreeable to the idea but on the other hand, they really only work on designs of their own interest and not what the competitions are about.

## Day 84 – Friction

Physics 11 – Today’s lesson is typically one of my favorites for the year.  Students brainstorm factors that affect friction and then they test out their ideas.  In the past I let the students have all the say in their work.  However, last year I noticed that several groups were doing pretty crazy stuff – mostly they weren’t measuring forces at all. In other words, they weren’t clear on what was the dependent variable in their experiment.

So this year I gave them more structure:

This helped with the experimental design but there was an unintended consequence.  The students gave up their agency. The day became more about me.  In general the students were asking “what do I do next?” and saying “I don’t know what to do.”

I’m not sure what I will do next year. If I had more time, I would run through the above sheet on a different experiment, and then let them figure it out for the friction inquiry.

Here is a link to the above Friction Experiment document.

## Day 83 – Dividing Fractions

Math 8 – Every now and then I resort to some notes and today was one of those days. We had modeled some simple division using counters, number lines and circle graphs.  However, at some point the models start to fall apart. Or, they become unweildy. At this point we turn to some mathematical properties to help with computing a division operation with fractions.

The students seem to be ok with this process. Once again, simplifying the fractions is by far and away the most difficult part for them.

## Day 82 – Newton’s Third Law

Physics 11 – One thing that I think I do very well in my physics class is set up foundations for some core understandings.  In general, my classes seem to have a relatively easy time with Newton’s Third Law.  This is because over time they are exposed to some key ideas:

1. a whole set of thought experiments on the nature of gravity and it having mutual, equal sized forces
2. labeling interactions on force diagrams
3. viewing an interaction using hoop springs as surrogates for force

We’ll see how the students do in testing, but in our peer instruction/voting, they perform quite well.