## Day 77 – Choices

Physics 11 – Some students have been coming for extra help.  There are two recurring themes with students in physics. Well, there are lots more but here are two.

1. Students are pretty good with graphical and diagramatic representions, but transferring those to actual equations is tricky for them, especially when dealing with symbols instead of numbers. I think many kids are on the threshold of formal reasoning.
2. Kids want to know how to get from A to B before they start solving a problem.  They’re not used to the idea of starting at A, trying something out, discovering something, and slowly working to B.

## Day 76 – Continue to Print

Engineering Physics – The class continues to fine-tune their designs while I print them out.  I’m starting to get a better idea of its capabilities in terms of resolution and what can and cannot be printed. So far the Printrbot Simples are working very well.

## Day 75 – Birthdays

Math 8 – Friday, 2:55 pm. First week back after the winter break. 13 year olds. Solution: join forces with another class and see how many people would have the same birthday!

I think there were 68 people in this photo (I didn’t really count). With 70 people there is a 99.9% chance that there will be at least two people with the same birthday. This group had 4 pairs. Fun!

Oh, earlier in the class we also did some work with modeling multiplication of fractions. I’m not sure how much more I will have the students pursue this. Whole numbers x fractions is easy to model and gives the students a physical/visual representation of what is happening with the operation. It removes some of the abstraction. I’m convinced that this modeling loses its shine as the operations get more complex as we move towards division. In my mind, models are simplified representations that help with explanations and predictions. By the time we get to dividing fractions, I think the models no longer accomplish what a model is supposed to.

## Day 74 – First 3D Prints

Engineering Physics – The first couple of groups starting printing their designs today. We are all learning with this process together. I wasn’t sure what kind of resolution we would get with the printers and it looks like many of the students are designing features that are less than 1mm in size. I know the resolution of the printers is better than 1mm but I don’t think it is good enough to print extrusions that are 1mm in size. It’s close though. This should lead to some good lessons on tolerances and limits of fabrication.

## Day 73 – Restaurants and Retirement

Math 8 – Today was a pretty good day. I started the lesson with warm-up using ratios/percents/rates. I brought in a receipt from a dim sum lunch that I had over the winter holidays. Most students did proper calculations although it certainly took a long time. I was left wondering how long it would have taken them if they were at the restaurant?

I was able to use this assessment to identify a few students that I will ask to come in for extra help. While we are finished the “percents unit” or topic, I can’t let them leave like this. All students can and should be competent in dividing a restaurant bill including tip. Even if they end up with a restaurant app on their phone, this problem is nearly identical to dozens of other situations that will require the same skills.

We then moved onto a group whiteboard problem with fractions (or ratios, depends how you look at it!). Nearly all groups first attacked the problem by finding a common denominator but then they realized that the number of married women wouldn’t match the number of married men. Hmmmm…