This question struck me a few minutes back, I was at a table with a pear. It was more narrow than round.I proceeded to rotate this pear in one swift movement. It rotated for a few seconds, and suddenly changed its orientation so that its axis of rotation was "vertical" instead of horizontal, and it stayed vertical till it stopped rotating. The same repeated every single time I rotated the object. but oddly this did not work when the initial force I applied was a small one. Does this happen with all objects? Why do objects tend to change their axis of rotation?