80 second physics demonstration showing the relationship between moment of inertia, I, and angular speed {omega} being conserved.

This system is analogous to moving masses about on a rotating spaceship. In this model, all the masses move in a spherically symmetric way, but that's not a necessary part of the law of conservation of angular momentum.




EDIT: the V-sauce video "Laws and Causes" gives a beautiful link between the conservation of angular momentum and forces. I can link that, too if you're interested.