Purpose: To demonstrate conservation of angular momentum.

Rotating stool, weights, bicycle wheel.

1. Sit on the stool with weights in your hands and with your arms extended outward to each side. Start yourself rotating slowly. Then pull the weights in close to your chest. Re-extend and again pull them in.
2. Have a student sit on the stool holding the rotating bicycle wheel with the axis of rotation horizontal. Rotate the wheel axis by 90^o about a horizontal axis. Rotate back to original position, and then 90^o in the other direction.

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