The Air Gyroscope is an apparatus that shows precession and nutation in a straight forward and understandable manner. It is a great apparatus for studying rotational motions. It is especially useful for studying the relationship between torque, and it's effect on the angular momentum of a rotating object.
The apparatus consists of a 4" ball bearing with a hole drilled into it. A narrow rod with moveable mass is mounted to the ball. Spin the bearing along the axis of the rod. If the sliding mass is located to exactly balance the ball and rod assembly there is no precession. Slide the mass so the rod end of the ball is heavy and the ball precesses in one direction. The precession can be tracked by following the direction the rod points. Slide the mass so the rod end of the ball is light and the direction of precession reverses.
By identifying the vector directions for the torque due to gravity and for the angular momentum one can predict the direction of precession. Interestingly, counter to intuition, the faster the ball spins, the slower is the precession.
In addition to precesion, nutation of a rotating body can be observed.
The ball floats on a layer of air reducing friction to an almost negligible value.
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