The spinning wheel will precess when it is suspended by its string.
To show gyroscopic action of a weighted wheel supported at one end of the shaft only.
special bicycle wheel, string
Spin wheel rapidly. Shaft of wheel will turn anticlockwise with the wheel rotating one direction. The shaft will turn in the opposite direction when the wheel is rotating the other way.
The folks over at HowStuffWorks demonstrate this. http://science.howstuffworks.com/gyroscope1.htm
Demo room information