Concept featured in film:Conservation of Angular Momentum/Moment of Inertia

VHS: 0:50:27-0:51:25

Play Flickclip Here (Quicktime)

Summary of clip: This clip is an excerpt of Doug and Kate practicing their ice-skating routine before Nationals. One can observe how in the various movements (positions) they distribute their mass differently around the center of rotation, thereby causing their rotation rate to increase/decrease. If all external forces are assumed negligible, their angular momentum is conserved.

Connection of flickclip to the concept:This is a good clip to introduce conservation of angular momentum. Ice-skating is the stereotypical example; therefore it is beneficial for students to see it in action.

Suggestions to Teachers:

1. Suggested questions for students when viewing the clip:

a.What happens when the ice-skater brings her arms in? How is her rotation rate affected?

b. What happens to her moment of intertia? Why?

c. Has angular momentum been conserved? Explain.

d. What if the ice-skater was more massive, would the results change? Explain.

2. Can you think of other examples of conservation of angular momentum? Students can investigate other situations such as hurricanes.

3. Demonstration: The teacher can have students "feel" conservation of angular momentum by having them spin on a chair with their arms outstretched. Bringing in their arms, they will spin faster.