Egg of Li Chun - Physical Explanation

Physical Explanation

No physical influence of other celestial bodies on the egg can affect its balance to the extent required by the folk belief. Gravitational and electromagnetic forces, in particular, are considerably weaker and steadier than the disturbances created by the person's breathing and heartbeat.

In 1947, Japanese physicist Ukichiro Nakaya verified experimentally that eggs in fact can be balanced with ease at any time of the year. He noticed that the shell of an egg usually has many small bumps and dimples, so that, by turning the egg in different directions, it can be made to touch a flat surface on three points at once, in many ways. It is not hard to find an orientation such that the triangle spanned by the three contact points lies right under the egg's center of mass, which is the condition for balancing any object. Of course, balancing an egg on a rough surface is easy too, for the same reason.

Martin Gardner also observed that "if you are convinced that an egg will balance more easily on a certain day you will try a little harder, be more patient, and use steadier hands. If you believe that eggs won't balance on other days, this belief is transmitted subconsciously to your hands", and compares the process to the "Ouija-board phenomenon".