Day 175: Momentum Concepts

Tuesday, 17 May 2016


We’re wrapping up learning about conservation of energy and prepping for the exam next week. Kids are feeling much stress, as is typical. We’re at that point in the prep cycle, though, that the super-on-it kids are highly stressed and the chill kids are super-chill. The divide is wide with few kids in between.

Tuesday night, I hosted Global Math Department with Tracy Zagar speaking. She talked about how to teach kids to relate ideas. While she focused on elementary mathematics, the topic stretches into high school science as well. Give the recording a listen this summer.

Day 174: Conceptual Review

Monday, 16 May 2016

Been thinking about the feedback I got from students that they don’t feel prepared for the conceptual questions I ask on tests, which has them worried going into the exam next Thursday. So, I came up with this idea: post a few questions on the board every day this week. I added them to Schoology with a poll so the kids who don’t have class that day can participate, too.

Schoology poll:

Screen Shot 2016-05-17 at 7.19.25 AM

On the board in the classroom and attached to the Schoology update:

Screen Shot 2016-05-17 at 7.19.32 AM

In terms of sheer participation, I had about a third of my kids across all classes participate in the poll. I’m writing this on Tuesday morning and I’ve just posted the second set of questions, so I’m eager to see if that was a one-time participation surge or if we can maintain it.

Day 172: Marble Ramps

Thursday, 12 May 2016


It’s conservation of energy time! And I’m so happy with the way this demo went to hook the kids:

  1. If we set up a race between these four large marbles, which one would win? (take bets, then release the marbles) Kids usually get this one right.
  2. Which marble is moving fastest at the bottom of the ramp? (take bets, release the marbles, then argue over how to tell) Kids rarely get this one right. Let’s try explaining what’s up. Hey kids, remember projectile motion? I have an easy way to compare marble speeds as they come off this ramp — watch where they land! (it was helpful here to have a slow motion video)

I did something quite similar last summer during summer school.

Day 166: Test Corrections

Wednesday, 4 May 2016


So I asked the above question on a test today. Plenty of kids got it wrong. In the majority of cases, what mistake did they make? Check out this kid’s work because it’s pretty typical:


He wrongly assumed the first ball wasn’t moving in the start of the problem. He proceeded to solve a conservation of momentum problem correctly in all other aspects. When he hit submit on his test, he saw that his answer was wrong. So he set about finding a correct solution and presented me with this correction:


Yay! Mistake found and solution corrected. (I’d prefer to see a few words along the lines of “originally I thought v1i was zero but clearly it is actually 2 m/s” but this is still pretty great!)

My testing setup:

  • Test is given online (this happens to be Moodle).
  • Students submit the test at the end and get immediate results. For some questions, I’ve configured feedback for common mistakes (such as “did you notice the sign on this one velocity should be negative?”). Though I can also configure partial credit automatically, I’d rather the kids think about what they did right to earn partial credit.
  • Students highlight partial credit or correct anything they can (rubric is below).

Screen Shot 2016-05-05 at 8.09.57 AM

Year-to-year feedback from students is that I’m quite generous in granting partial credit. Maybe that’s true but I just feel like you have to know nothing to get no credit on a problem on one of my tests. For instance, identifying all the given values will earn you 25% credit.

BTW, I love this topic and write about it pretty much every time I give a test.