Aeolipile

An aeolipile, aeolipyle, or eolipile, also known as a Hero's (or Heron's) engine, is a simple, bladeless radial steam turbine which spins when the central water container is heated. Torque is produced by steam jets exiting the turbine. The Greek-Egyptianmathematician and engineerHero of Alexandria described the device in the 1st century CE, and many sources give him the credit for its invention. However, at least one source credits Vitruvius as the first to describe this appliance in his De architectura (c. 30–20 BCE).

The aeolipile is considered to be the first recorded steam engine or reaction steam turbine, but it is neither a practical source of power nor a direct predecessor of the type of steam engine invented during the Industrial Revolution.

The name – derived from the Ancient Greek name Αἴολος and the Latin word pila – translates literally to 'the ball of Aeolus', Aeolus being the Greek god of the air and wind.

Because it applies steam to perform work, an aeolipile (depicted in profile) is used as the symbol for the U.S. Navy's Boiler Technician Rate, as it was for the earlier Watertender, Boilermaker, and Boilerman ratings.