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Spinning Tops, Angular Momentum, and Gyroscopes

If you understand the principle of a spinning top, you will understand how your bicycle works (how it balances).

If you place a top on a table and merely try to stand it up, it will fall over.  Now spin the top and it miraculously stands up.  The spinning action of the top “stabilizes itself” and resists falling over from the force of gravity.  The spinning top has Angular Momentum, a vector quantity, and is equal to the angular velocity times its mass, or m x .  Angular momentum is conserved such that the top wants to stand upright while spinning even if you give it a slight blow.  It resists any side forces, such as gravity or a blow of wind, to conserve angular momentum.


Tops Have Angular Momentum m x


A bicycle wheel has the same stabilizing effects as a spinning top.  While it is spinning at an angular velocity, it wants to resist any lateral forces and keep its position.  It is resisting gravity from tipping it over, and the faster and faster a bicycle wheel turns, the more stable it becomes.

An instrument used in navigation is called a ‘gyroscope’ and is similar in principle to a spinning top.  Sometimes a bicycle’s ability to balance itself so well is said to be from the “gyroscope effect.”  But a gyroscope is the same as a spinning top and all one needs to know to understand how their bicycle works is how a spinning top works.