The following is an excerpt from Using Physics Gadgets and Gizmos, Grades 9-12: Phenomenon-Based Learning that demonstrates classroom application of the Power Ball Gyroscope:
The Power Ball Gyroscope demonstrates the significance of torque. The greater the angular velocity of the rotor, the greater the force needed to change the orientation of the gyro ball. Torque is a quantity that describes the rotating effect of a force. Torque (τ) can be defined as the cross product of the position vector (r) and the force (F):
τ = r x F
The position vector is the vector from the axis of rotation to where the force is applied. The direction of the torque vector is given by the right-hand rule (Figure 8.13): If your index finger is pointing in the direction of the position vector and your middle finger points in the direction of the force vector, then your thumb points in the direction of the torque. The time (t) rate of change of the angular momentum is equal to the magnitude of the torque, which, in the exploration, was expressed as:
τ = Δ L/Δ t
In the limit as Δt approaches zero, this is written as a derivative:
τ = dL/dT
The greater the angular momentum, the greater the torque (i.e., the greater the force) needed to significantly change the direction of the angular velocity. The resistance to changes in the direction of the angular velocity (or the direction of the axis of rotation) is easily detected when the angular velocity of the rotor increases. The Power Ball Gyroscope will roll on the floor only if the direction of the angular momentum vector stays constant. A change in angular momentum would require a significant torque, so the ball tends not to roll.
Source: Bobrowsky, M., M. Korhonen, and J. Kohtamäki. 2014. Using physics gadgets and gizmos, grades 9–12: Phenomenon-based learning, pp. 112–113. Arlington, VA: NSTA Press. Reprinted with permission from the publisher.
Power Ball Gyroscope features:
Spins up to 13,000 RPMs
Delivers more than 38 lbs of resistance
PowerStart Docking Station
2 AA batteries