Hannah+Sather

Sadd Al-Kafara, the world’s first known dam, was built around 2950-2750 B.C by ancient Egyptians. In Arabic, Sadd Al-Kafara means “Dam of the Pagans”. It was a gravity dam, meaning that the weight of the dam itself retains the water. It was estimated to be thirty-seven feet tall, 348 feet wide at the top and 265 feet wide at the bottom. Sadd Al-Kafara took ten to fifteen years to build. It was apparently poorly constructed and was mostly demolished soon after it was built. This was an important innovation in human history; it has led to greater innovations such as different types of dams and hydroelectricity.

Lester Allan Pelton Birth: September 5, 1829 in Vermilion, Ohio Education: No information Interesting facts: ·  Pelton moved to Camptonville, CA during the gold rush. ·  He made a living as a carpenter and millright. ·  He was observing a water wheel when he came up with his invention. ·  Pelton was granted a patent in 1889 ·  He died on March 14, 1908. The Pelton wheel was invented in 1878 by Lester Allan Pelton. It is a type of free-jet water turbine with double cups and a wedge-shaped divider in the middle. At the time, there was a great demand for power sources to run the machinery and mills needed in the gold mines. Steam engines were the main source of power, but they required large supplies of wood or coal. There were abundant streams and waterfalls around; CONTINUE HERE Pelton came up with the invention after watching a water wheel malfunction. The water hits the edge of the cups, directing the flow in a half-circle, making the turbine move faster. It improved efficiency greatly from regular water wheels of the time; in 1883 it won a competition for the most efficient water wheel turbine held by the Idaho Mining Company.