 The display demonstrated a series of electrical effects related to alternating current, AC generators, and displayed many types of induction motors and explained the rotating magnetic field that drove them.With the fair celebrating the 400th anniversary of Christopher Columbus's arrival in the New World, the "Egg of Columbus" exhibit, building on the apocryphal 15th century story of the "Egg of Columbus" (where the explorer stood an egg on end by smashing its bottom), is described as going "one better" by using a magnetic field to stand an egg on end.It presented the viewer with a flat round wooden surface surrounded by a wooden rim.