Day 5

11:32 P.M.

Block 5,6 (Physics 1,2)

I am beginning to think that what I really needed was a couple of days in the classroom to get warmed up. Today went much more smoothly.

I finished up the Earth Moon lab with all my students and I felt much more confident about nailing the 3-Act challenge.

Act 1)

I did a few things differently this time. I used to try to limit student questions or somehow control what they would ask by judging the questions (“I don’t know if we want to ask that.”) which I realize now kills student engagement and doesn’t make them want to risk asking questions. This time I wrote down every question. Here are a list of some of the questions:

  • What is the Earth’s orbit?
  • How fast are they going?
  • What’s the mass of each of them?
  • What’s the gravitational pull of the Earth on the moon?
  • What would happen if the moon actually crashed into the Earth?
  • Why isn’t this printed in color?
  • Are these to scale?
  • Why are they so close together on the paper?

This time I went through questions like “Why isn’t this printed in color?” and gave honest answers. “Because we don’t have a color printer. This might actually be a drawback, because if you were able to see a color map of the globe and make out some continents, you might actually have a hint at your disposal for what we are about to do.”

Or, “What would happen if the moon crashed into the Earth?” “That’s one we would not get out of alive. Luckily the estimate the moon is receding from us at the rate of a few inches a year. In about 2 billion years we won’t have a moon if I remember correctly.”

I was able to do this because I actually timed out each “Act”.

One student raised his hand and boldly said something like this: “Okay, this is totally irrelevant,t but it’s driving me crazy. If I fly a plane and it’s going with the rotation of the Earth shouldn’t it be going faster than if it’s going against the rotation of the Earth?”

I absolutely love questions like this, and I promise him that he would be able to answer that question soon enough. (Later on he was also the student that had the best estimate for the Earth-Moon distance and the first in his block to calculate the correct scaled answer.)

This leads me to believe that the 3-Act math problems can really be a way to create a safe community in a classroom. Students should feel truly free to ask any outlandish question they want, provided I am empowering them to seek those answers in the material we are studying. I don’t have to deflect questions, nor do I have to go off on tangents cynically hoping to generate interest via tangential topics.

If the question they ask is a topic we haven’t got to yet, what a great opportunity to file away an idea for future use.

I wanted to share out a result that one of my students got:

Screen Shot 2013-08-27 at 11.51.13 PM Screen Shot 2013-08-27 at 11.51.22 PM

Block 1 (AP Physics)

Today I did a 15 question review to get the students used to the idea of Multiple choice on the AP. Specifically I had them do 15 questions in 25 minutes off last years final exam. The goal was two-fold: time them to get them used to it, and give them review problems to see where they are.

It just occurred to me know that I should grade them using AP scaling to build their confidence as many of them remember only 70% of the material which would give them a 5…

To review problems they don’t know I have taken to constructing mini challenges and giving them manipulatives. For example I gave them a bouncy ball today (to keep!) and gave them the following directions:

1) Drop a bouncy ball from 1 m and catch it on the rebound

2) What is the dissipated energy?

3) What is the impulse given to it by the floor?



Clearly they are a little rusty judging by the impulse calculation. But this is exactly the kind of thing I want to diagnose. One thing I like about whiteboards and toys is that students are way more engaged than they would be with a worksheet that has exactly the same problem. (A ball is dropped from  a height of 1 m and rebounds to 0.8 m. Assuming its mass is 0.5 kg… )

Eventually of course I will need to practice AP problems with the students, but I’d like the honeymoon to last a little longer as they need to get comfortable with doing physics again and rebuilding basic competence.


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