An interesting physical phenomenon, which contradicts our common sense, is concerned with the dynamics of motion of a spinning ellipsoid in a non smooth surface. A hard-boiled egg spinning on a table with a rough surface is an example. In this article, we present a theoretical explanation of the dynamics of motion of this ellipsoid, that describes the axis raising phenomenon, from the horizontal to the vertical. The equations of motion were obtained with the Lagrangian formalism.
analytical mechanics; rigid-body rotation; homemade experiment
