## Day 128 – Collision Analysis

Physics 11 – Students were given two options to analyze and report on a collision.  One option was to analyze two carts exploding apart (spring plunger activated), where one cart has an unknown mass on it. Option two was to analyze the impulse given to a popper toy.

Almost everyone chose the popper. It was the harder one to analyze because students had to incorporate projectile motion in order to complete their analysis.

## Day 127 – Circuit Analysis Tool

Science 9 – Here is a tool I showed the students to use for analyzing circuits. They color code wires in a circuit according to high (purple) and low (blue) pressure.  A wire has equal pressure at all points.  In order for a bulb to light, they know there must be a pressure difference across the bulb, because charges move from high pressure to low pressure.  Tracing and colour coding the wires lets the students see which bulbs have a pressure difference and which ones don’t. We then quickly checked the circuits in real life to see that they agreed.

Once a person gets more comfortable with looking at circuits and schematics, they can easily identify a short. However, this is a great bridge between what they they’re learning (pressure differences) and what they can do (predict bulbs lighting).

## Day 126 – Models

Physics 11 – Today was mostly seatwork/practice. However, I did spend a bit of time going over models.  Even though it’s something that they’re supposed to be working on all year, I get the feeling that I call these things models and the students just think of them as a list of things “to know.”

## Day 125 – Water Analogy

Science 9 – Sometimes I worry if the students are not seeing the forest through the trees by working through all of the lab ideas.  Today I gave the students this as part of some practice.  Without having to read about the water analogy for circuits, all students were able to do this correctly.  Ok, it’s not the most difficult thing in the world but it gives me confidence that they are learning something.

## Day 123 – Bulbs in Parallel

Science 9 – Students continued with their circuits. Today’s results were really surprising to everyone.  By adding another bulb in parallel, the bulbs didn’t go dimmer!  This was a shock to everyone.  I tried to help them to understand what was happening by using an analogy of blowing through one small straw vs blowing through three small straws at once.  Unfortunately I didn’t actually have the straws and many kids thought three small straws would be harder to blow through.

Note to self: have a box of stir stick straws in class next year.

## Day 122 – Whiteboarding CoM

Physics 11 – Whiteboarding last day’s results was the main even for today but I forgot to take pictures.  By going around the room from whiteboard to whiteboard I posed the question, “what pattern do you see?”  Inevitably the students start to see that in each case, the moment of the objects before the interaction is equal to the momentum of the objects afterwards.  Ah ha! Conservation of Momentum!

I then showed the students how conservation of momentum can also be seen as a consequence from Newton’s Third Law.