College-Prep Physics: Today we discussed scenarios 1-5 from the bowling ball and mallet activity. I like discussing the similarities and differences between Scenarios #1 and #2, and between #3 and #4. Often times kids will hit the bowling ball once to start/stop it, so asking for gentle taps is a great way to see even tiny forces can eventually yield high speeds or bring an object to a stop.
Scenario #5 always brings up debate about the effects of friction, and if scenario #1 and #5 should look the same or different. So we quickly determined if a rolling bowling ball maintained a constant speed once set in motion. Then we played with the hoverdiscs and rode the hovercraft. We’ll finish with scenarios #6-8 tomorrow.
NGSS Science and Engineering Practice #2: Developing and Using Models
College-Prep Physics: We did the bowling ball and mallet activity today as an introduction to forces and motion. Why do things speed up, slow down, or change direction? One of the tasks asks students to use the mallet to get a moving bowling ball to make a 90 degree turn. What to do is not obvious to students. They just want to hit the ball at right angle. In the video, you’ll hear one group come to terms with their incorrect prediction and how they fix it. They are learning directly from their experience — more powerful and longer lasting than simply listening to me lecture!
I improved my handout from last year, changing some wording and adding a few additional scenarios. You can get it here: WORKSHEET Bowling Ball Motion 2015
We hadn’t done motion diagrams before, so before we played with the bowling balls, I started the lesson with this slide:
The strobe photos came from The Physics Classroom Photo Gallery. The photos made for the best introduction to motion diagrams I’ve ever had.
NGSS Science and Engineering Practice #8: Obtaining, Evaluating, and Communicating Information