Here's a little experiment you can try...
First of all get a rotating round surface (I did it with a rotating stool...), then get a plastic stick (like a sipping straw but longer and wider, the main point is that it must be hole inside), and cut it seccionally. Then place it in a radial postion (it must stick out of the surface) and finally place a little ball in the straw, in the center of the surface (it must fit in the straw's cavity)
Now you are ready for this brief experiment.
Gently start spinning the rotating surface, and watch.
Let me know if it worked.
Ms. M
P.S.: My english isn't very good, I live in a spanish-speaking country, I hope you understood the procedure, if you have any doubts please let me know