Yet another use for an Archimedes invention:
(from the NYT's science desk)
An Archimedes-inspired generator in England ... it is a mundane contraption attributed to the great Greek mathematician, inventor, engineer and military planner — the Archimedes screw, a corkscrew inside a cylinder — that has a new use in the 21st century. For thousands of years, farmers have used this simple machine for irrigation: Placed at an angle with one end submerged in a river or a lake, the screw is turned by a handle, lifting water upward and out at the other end.A couple of decades ago, engineers found that running an Archimedes screw backward — that is, dropping water in at the top, causing the screw to turn as the water falls to the bottom — is a robust, economical and efficient way to generate electricity from small streams. The power output is modest, enough for a village, but with a small impact on the environment. Unlike the turbine blades that spin in huge hydropower plants like the Hoover Dam, an Archimedes screw permits fish to swim through it and emerge at the other end almost unscathed.Such generators have been built in Europe, including one commissioned by Queen Elizabeth II of England to power Windsor Castle; the first in the United States could start operating next year.
