Tuesday, July 29, 2008

Egyptian Pyramids

The Egyptians continued to construct taller and taller pyramids and started smoothing out the jagged edges of stepped pyramids. One of the earliest attempts was the Meidum pyramid, in 2570 B.C. It had seven steps progressing to eight, but
it collapsed and was abandoned.
Pyramid designers learned that if pyramids were going to be higher and have steeper slopes, their bases needed to be wider.
At Dahshur, further upstream along the Nile from Saqqara, laborers started the construction of a pyramid for the Fourth Dynasty pharaoh Sneferu. Unfortunately, the designers chose a poor foundation, and the pyramid began to lean inward upon itself when it was about two-thirds complete. The builders reduced the angle of the upper portion to complete it and make it more stable, and it is now known as the Bent Pyramid (2565 B.C.).
Unsatisfied with the Bent Pyramid, Sneferu ordered another pyramid at Dahshur. The designers chose a better foundation and made this pyramid the same height as the Bent Pyramid, but with a wider base and a shallower angle. The Red Pyramid was completed in 2560 B.C.

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

How Pyramids Work-2

How Were the Pyramids Built?
Pyramid construction is a continuously debated topic. There are no existing records of building plans or discussions of construction methods, so no one knows exactly what happened. Of course, archaeologists and engineers have plenty of ideas -- some sound far-fetched and others seem more reasonable. We'll use the Giza pyramids as an example because we have the most information on them.
Let's break the task of building the pyramids into components:
Surveying and excavation: choosing a suitable site, orienting it and preparing the foundation
Obtaining building materials: quarrying rocks or making huge stones
Transporting building materials: transporting from the quarrying site to the pyramid
Workforce logistics: finding skilled workers, feeding them and housing them
Surveying and Excavation
Egyptian builders probably made plans and models of the pyramid. The projects were overseen by the pharaoh's master builder, or vizier.

The collapse of the Meidum pyramid and the shift of the Bent Pyramid taught builders that foundations were important. Once engineers found a suitable site with a good foundation, they had to lay out the site.
Pyramid sides always ran parallel to the north-south and east-west axes. The builders didn't have compasses, and there was no North Star at the time (the Earth's rotation wobbles like a top, and the position of true north in the sky changes over a 40,000-year cycle). So, they used the movements of circumpolar stars or the sun to figure out true north. Using sighting rods and circles, they could trace arcs of the rising and setting stars or the sun's shadow, measure the angles to the ends of the arc, and calculate true north. Once they established that, they could find the other directions with lines and right angles.
The ancient Egyptians used "cubits" (the length from the tip of your middle finger to your elbow) and "hands" (the width of your hand with the thumb on the side) for measurements. They dug post holes at regular intervals (10 cubits) along the base outline and laid out the site in a grid.
Then, laborers excavated and leveled the foundation. No one is sure of the exact method, but they were extremely exact -- the base of Khufu's pyramid is level to 2 centimeters (less than an inch).
There are two main theories about leveling methods:

1) Workers poured water into the excavated site and leveled all material above the waterline. Then they lowered the water level and removed more material, continuing the process until the foundation was level.

2) The builders installed posts at regular intervals. A line, leveled with plumb bobs, was pulled taut across the posts at a reference mark to ensure alignment. Then they could excavate the foundation down to the reference marks.

How Pyramids Work -1

The Great Pyramid of Khufu
The Giza pyramid complex, on the west bank of the Nile, is the most famous group of pyramids in the world. As we discussed earlier, the grandest pyramid was built for Sneferu's son, Khufu, in 2540 B.C. The two smaller pyramids nearby were for Khufu's son, Khafre, and his grandson, Menkaure. After this dynasty, great pyramid building stopped, probably because of the time and expense of these massive state projects.
The Great Pyramid of Khufu on the Giza plateau in Egypt is the largest and most elaborately constructed pyramid in existence, representing the most advanced aspects of pyramid construction. Khufu's pyramid has the following features:
The primary burial chamber, or king's chamber, contains the sarcophagus (tomb) that held Khufu's body, and the walls are adorned with hieroglyphs (writing) depicting various aspects of ancient Egyptian history and religion.
The smaller queen's chamber (actually a misnomer -- it was not intended for the queen) lies within the pyramid, while another unfinished secondary burial chamber lies underneath the pyramid.
Weight-relieving chambers above the king's chamber distribute the weight of the overlying rock and prevent the king's chamber from collapsing.
The gallery is a large passageway with a vaulted, corbelled ceiling (the walls are layered upward, and each vertical layer sticks out further than the one below to form a primitive arch).
Descending and ascending passageways connect various chambers to each other and to the outside.
Air shafts connect the king's chamber to the outside. They may have been designed as a way for Khufu's spirit to exit the pyramid and rise to the heavens.
The entrance was sealed after the pharaoh's body was placed inside.
White limestone rocks line the pyramid's exterior, giving it a smooth face. These rocks have eroded away over time, but we know they existed because the Pyramid of Khafre still has some on its peak.

Pyramid of Userkaf

There are over 100 pyramids in Egypt. Many, like the pyramid of Userkaf located near the step pyramid of Djoser, have become piles of rubble.This pyramid was built during the 5th dynasty

Inside The Red Pyramid

Now, you enter the Red Pyramid for the first time.The original height of the pyramid was approximately 343 feet, while each side measured 722 feet. Modern steps have been installed to ease the ascension to the opening which is 94 feet above the ground level and between 12 - 13 feet east of center. Here is the internal layout of the pyramid, which consists of three chambers:
The first passageway descends at an angle of approx. 27 degrees at a length of approx 206 feet.

The end of the descending passageway empties into a level corridor that is approx. 25 feet long. This corridor leads into the first of three chambers.
The first chamber has a magnificent corbelled ceiling consisting of 11 courses and climbing to a height of approx. 40 feet.
At the south end of the chamber there is a opening into a second short passageway, which leads to the second chamber.
The second chamber has similar dimensions to that of the first. It is exceptional in that it is one of the only pyramid chambers to lie directly beneath the centerpoint or apex of the pyramid. At the south end, a staircase has been installed to allow access to the final chamber, the entrance for which is located approx. 25 feet above the floor of this second chamber.

The top of the stairs lead to a final passageway which is about 23 feet long. This passageway ends at the third and final chamber.
The final chamber is believed to have been the actual intended burial chamber. It's dimensions are approx. 14 x 27 feet with a final corbelled ceiling rising to a height of 50 feet. The floor has been systematically removed to a depth of 14 feet in a search for other passageways and chambers in this pyramid. No such other features were ever found.

Red Pyramid

The Red Pyramid was built by Senefru and is 105 meters tall. It is the third tallest pyramid in Egypt, after the Cheops and Chefren pyramids in Giza.
The Red Pyramid is considered to be the first true pyramid and is made of sandstone.
The entrance is made of red stones.

Step Pyramid of Djoser

The step pyramid of Djoser is located at Saqqara, just south of Memphis. The pyramid started out as a mastaba. It was then expanded six different times to six levels to the height of over 200 feet.
The architect credited with it's designs was the kings vizier named Imhotep.
This marks a large step in architectural design and size of buildings among early people. The pyramid was built during the 3rd dynasty around 2630 B.C.

Bent Pyramid of Dashur

The Bent Pyramid in Dashur was built during the end of the reign of Humi of Dynasty III into the beginning of Sneferu's reign which started the Forth Dynasty.
The uniqueness of this pyramid is in the fact the angle of the wall was changed in mid-construction. It started at 55° up to 154 feet.
The angle then was changed to 43° from there to the top of the pyramid. The total height of the pyramid was almost 344 feet.

Pyramid of Menkura

This third built for Menkura, grandson of Khufu, is much small then the other two on the Giza plateau. It's height is 218 feet, less than half of the other two pyramids.
The base measures 343 feet. Next to the pyramid are three much small pyramids.

Pyramid of Khafre

The second largest pyramid is that of King Khephren, son of Khufu. This originally stood 473 feet high. It appears to be taller than Khufu's pyramid, because it is built on higher ground.
The pyramids base is about 706 feet long. In front of the pyramid is a causeway which leads to a valley temple.
Near the valley temple the famous sphinx was carved out of an outcrop of limestone.

Great Pyramid of Khufu

The Great Pyramid of Khufu (Cheops) is one of the largest structures built by man even today, 4,500 years later. It is estimate that 2.3 million blocks averaging 2.5 tons a piece were used in the building the pyramid.
Weight of the block ranged from 2 to 15 tons. The pyramid sits on 13.5 acres of land and is a height of 480 feet.
The length of its sides are 756 feet. It is estimated to have taken 100,000 men over 25 years to build the pyramid


The great pyramids of Giza are located just south of present day Cairo. The three pyramids were built during the 4th dynasty of Egypt.
They pyramids are those of Khufu (Cheops), Khafre (Chephren), and Menkure (Mycerinus). They were constructed over 4,500 years ago and show us the power and wealth of the pharaoh in the Old Kingdom. Each had a mortuary temple and causeway.
Below is a basic map and lay out of the area on which these three pyramids were built.