Spinning Rattleback and Angular Momentum

Abstract

Download video below
Download video below

Conservation of angular momentum is explored with the strange behaviours of the spinning rattleback by operating it on an air table. See video below.

Portable

Yes

Principles Illustrated

The apparently magic spinning rattleback changes its direction of rotation when spun clockwise but not when spun counterclockwise. It will start spinning when one end is pressed and released. How is this consistent with conservation of angular momentum? When the rattleback is operated on a plastic sheet on an air table it becomes clear how angular momentum is conserved.

Momentum is conserved ...
Momentum is conserved …
... and so is angular momentum
… and so is angular momentum

 

 

 

 

 


Video:

Download video (right-click and “save link as”): Spinning Rattleback.m4v

NCEA & Science Curriculum

PHYS 3.4 and tertiary

Instructions

The plastic sheet should have a moment of inertia that is comparable to the moment of inertia of the rattleback, and you need quite a lot of air flow. Our air tables are portable with some difficulty but we will bring them to Wellington area schools.

Safety

Individual teachers are responsible for safety in their own classes. Even familiar demonstrations should be practised and safety-checked by individual teachers before they are used in a classroom.

Related Resources

Teaching Resources

Would you like to contribute lesson suggestions? Contact us.

References

Credits

This video was produced by Victoria University Stage One Students (first year university students) Bethan Cropp and Huyen Nguyen with limited help from staff. High school students and university students are welcome to submit resources.

The development of this resource was supported by the MacDiarmid Institute.

This teaching resource was developed with support from

The MacDiarmid Institute
Faculty of Science, Victoria University of Wellington
School of Chemical and Physical Sciences, Victoria University of Wellington

Copyright

Copyright and fair use statement