Aeolipile

An illustration of Hero\'s aeolipile

An aeolipile, a rocket-likeNASA Glenn Learning Technologies Project (LTP) jet enginejet engine invented in the first century by Hero of Alexandria, is considered to be the first recorded steam engine and reaction steam turbine."turbine." Encyclopedia Britannica. 2007. Encyclopedia Britannica Online. 18 July 2007 <http://www.britannica.com/eb/article-45691>. The name—derived from the Latin words "aeoli" and "pila"—translates to "the ball of Aeolus" ; Aeolus being the Greek god of the wind.

Features

It consists of an air-tight chamber (usually a sphere or cylinder) rotating on a bearing of some kind, with bent or curved nozzles projecting from it (tipjets), through which steam is expelled perpendicular to the bearing axis. The resulting thrust due to the rocket principleaeolipile causes a torque which makes the device spin (Newton\'s third law).

A modern replica of Hero\'s aeolipile

Typically, the water is heated in a basin, which is connected to the rotating chamber by a pair of pipes that also serve as the pivots for the chamber. However, the water may also be heated in the chamber itself as shown in the illustration.

A classroom model of an aeolipile

The device was thought of as little more than a diversion during Hero\'s lifetime, although it was used to operate temple doors, but the device received little serious recognition until relatively modern times.

See also

Wikimedia Commons has media related to:

Aeolipile

• Steam engine
• Hot water rocket
• Rocket engine
• Segner-wheel

References

External links

• Building a replica of the aeolipile (includes a history of the aeolipile and an explanation of the principles behind it).

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