A friend showed me a tippe top (a special kind of spinning top) lately and asked me about the physics behind it. I thought about it for a while but cannot quite figure it out. So I will throw the question to SE. Below is a picture of tippe top:
So basically the strange effect is that when you spin such a top fast enough with its round surface touching the table, the top will wobble and eventually invert itself. There is a video of this effect at wiki commons and here is an illustrative picture:
So my questions are:
- Why is the top so unstable? Why does it invert?
- Why does the initial angular velocity of the top matter? (Why do we have to spin faster than a certain velocity in order for the top to invert?)
- What other shapes will lead to inversion?
I am looking for some intuitive explanations that do not involve too much mathematics. Heuristic approaches are welcomed!