This two and a half minute video shows the phenomenon of a bowling ball being swung as a pendulum. A person releases the ball in front of a volunteer’s face and the video shows what happens as the ball swings away and returns. The video can be used within an instructional sequence to help students understand that energy cannot be created or destroyed but that the way that it manifests itself in a system can change. The audio in the video provides an explanation of the phenomenon which would likely discourage students from developing their own ideas about the phenomenon. Therefore, the video should be shown without sound or the setup can be replicated in the classroom as a demonstration (with proper safety considerations).
The phenomenon can be used to prompt the following driving questions:
- Why is the man in the video certain that the bowling ball won’t hit the woman’s face?
- In what ways is giving the bowling ball a push different than just releasing it and why is it different?
- What happens to the speed of the bowling ball as it goes back and forth?
- Why doesn’t the bowling ball make it all the way back to where it was released?