A bicycle wheel is mounted on a rod, and a string is fixed on the end of the rod. The system is hung to the ceiling of the classroom by the string. Make the wheel spin by using an electrical motor with friction wheel. Due to the gravitational torque, the wheel will precess about a vertical axis when it is spinning. The instructor then places an additional torque on the system by trying to force the precession around the vertical axis. When he does this (with some practice) the angular momentum of the wheel will align itself with the applied torque, i.e., the gyroscope will rise to a vertical position.
|Bicycle wheel with rod
|hook on the ceiling
|electrical motor with friction wheel.