Tippe Top
A top without a clear up side.
tippetop1.jpg
Figure 27: It starts like this
Concepts
Torque, friction, precession, rotational inertia, unstable equilibrium

Materials
Tippe Top, hard surface to spin it on

Procedure
Prior to spinning, have students make observations of the top and predict what its motion will be like while it is spinning. Then allow them to spin the Tippe Top on a hard surface. In order for the top to invert they will need to spin it with a amount of force. It may take some students more than one try to cause it to rotate upside down.

Results
Have students describe the top after it was spun. Additionally, have them do their best to explain why the top inverts itself.

Explanation
When the top is spun a frictional force is generated in places where the top comes in contact with the ground. The friction causes the top to precess, and the act of precession in conjunction with the friction generates a torque. The torque causes the top to eventually invert itself. While spinning on the handle the top is in a state of unbalanced equilibrium. Once it stops spinning, the top loses it rotational inertia and gravity causes it to topple back over to the position where it started (or thereabouts).

tippetop2.jpg
Figure 28: But ends like this


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