Monday, June 28, 2010

ARCHIMEDES

Archimedes (287-212 BC) was a prolific ancient Greek mathematician. Archimedes invented the water screw, a device for raising water using an encased screw open at both ends. The screw is set an an angle, and as the screw turns, water fills the air pockets and is transported upwards. The Archimedes screw is still in use today. Among his many accomplishments was the first description of the lever (around 260 BC). Levers are one of the basic tools; they were probably used in prehistoric times. Many of our basic tools use levers, including scissors (two class-1 levers), pliers (two class-1 levers), hammer claws (one class-1 lever), nutcrackers (two class-2 levers), and tongs (two class-3 levers).

ANEMOMETER

The anemometer is a device that measures the speed of the wind (or other airflow, like in a wind tunnel). The first anemometer, a disc placed perpendicular to the wind, was invented in 1450 by the Italian architect Leon Battista Alberti. Robert Hooke, an English physicist, later reinvented the anemometer. In 1846, John Thomas Romney Robinson, an Irish physicist, invented the spinning-cup anemometer. In this device, cups are attached to a vertical shaft; when the cups spin in the wind, it causes a gear to turn.