The Egg of Columbus reference article from the English Wikipedia on 24-Apr-2004
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Egg of Columbus

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The Egg of Columbus is a story about Christopher Columbus that takes place at a dinner which a Spanish gentleman had given in his honor. The story is used to illustrate his skill at practical judgment and evaluation. This story may be a derivative of one which holds Filippo Brunelleschi, instead of Columbus, makes the proposition. The Brunelleschi story is set before he won the contract to build the dome of the cathedral of Florence.

In the story, Columbus asks the gentlemen in attendance to make an egg stand on end. After the gentlemen successively tried to and failed, they stated that it was impossible. Columbus then placed the egg's small end on the table, breaking the shell a bit, so that it could stand upright. Columbus then stated that it was "the simplest thing in the world. Anybody can do it, after he has been shown how!"

There is a monument to Columbus' egg in San Antonio, Ibiza.

Table of contents
1 Tesla's Egg of Columbus
2 Puzzle
3 Further readings
4 External links and references

Tesla's Egg of Columbus

Topics related to Nikola Tesla
Tesla, SI unit
Tesla patents
Wardenclyffe Tower
War of Currents
Egg of Columbus
Tesla coil
Tesla turbine

Nikola Tesla, at the 1893 World Columbian Exposition, demonstrated a device he constructed known as the "Egg of Columbus". The device was used to demonstrate and explain the principles the rotating magnetic field model and the induction motor. Tesla's egg of Columbus performed the feat of Columbus (without damaging the egg) using rotating magnetic field. The egg "levitates" against the Earth gravitational attraction. The egg's major axis spin is controlled by electromagnetic levitation.

Tesla's device used an toroidal iron core stator on which four coils were wound. The "egg" is composed of copper. The device was powered by a two-phase alternating current source (such as a variable speed alternator) to create the rotating magnetic field. A six coil polyphase system would work, also. The device operated between the frequency from 25 to 300 hertz (eg., the ELF band in the electromagnetic spectrum). The ideal operation frequency was described as being between 35 to 40 hertz. A reproduction of the device is displayed at the Belgrade Nikola Tesla Museum.


Egg of Columbus can refer to a puzzle of which originated in the 19th century (China). This is a variation of the types of puzzle (known more generally as a tangram) which consist of pieces divided and arranged to match particular designs.

Further readings

External links and references

General story

Tesla's device Puzzles