Tuesday, July 29, 2008

How Pyramids Work-3

The pyramids were built of limestone, granite, basalt, gypsum (mortar), and baked mud bricks. Limestone blocks were quarried at Giza and possibly other sites. Granite likely came from upriver at Aswan.
Alabaster came from Luxor and basalt from the Fayoum depression
Iron tools were not available, so workers used copper and stone-cutting tools to carve out the blocks in the quarries. They then used levers to move the stone blocks away from the quarry site.
Transporting building materials
Again, no one knows how laborers were able to get the 2.5-ton stone blocks from the quarries to the building site. Wheels wouldn't have been useful on the desert sand and gravel, so they most likely dragged the blocks with wooden sleds and ropes.
Some think that workers used quarter-circle wooden sleds that fit around a rectangular block. They attached the sleds to the block, and a crew of about eight men rolled them along the ground, much like rolling a keg of beer. Others say the laborers used wooden rollers.
For long-distance transport, the blocks were loaded on barges and transported down the Nile. Workers dug canals to get the barges nearer to the site
­­Egyptologists estimate that workers placed­ about 300 stones a day during pyramid construction. Several theories -- lever systems, ramps and kites, for example -- attempt to explain how the huge blocks got into place. Those in the know generally accept the ­ramp idea, but they debate the exact ramp configurations.
The ramps could have been long and straight, perpendicular to the sides or wrapped around the core.
While laborers placed stones in the core, stone cutters were making the chambers, passageways and shafts in the pyramid's interior. Artists inscribed the designs that adorned the chamber walls. Let's take a closer look at the workers who built the pyramids.

The Greek historian Herodotus described the building of Khufu's pyramid by more than 100,000 slaves. Hollywood seized upon this image of slaves and their taskmasters in movies like "The Ten Commandments." But when Harvard archaeologist Mark Lehner led an expedition to uncover clues about the people who built the pyramids, he found no evidence of housing for such a large population. Instead, his group discovered housing and food storage places for small gangs of workers.
It appears that at any one time about 2,000 workers were on site, divided into two large divisions and smaller groups of about 200 men. The evidence indicates that they were probably paid and well fed. The working groups were periodically rotated over the years of pyramid construction, and the total workforce may have been about 30,000 [source: Harvard Magazine].
Pyramid building stopped in Egypt long ago. When the Spanish conquered the Aztecs and Mayans, the Central American pyramids were abandoned in the jungles until archaeologists uncovered and studied them.
Archaeological research continues on these structures today to resolve the many mysteries of how they were built