SECTION 89: ARCHITECTURE PYRAMIDS

Transcription

1 SECTION 89: ARCHITECTURE PYRAMIDS Lesson Objective(s):»» The student will be able to explain how the ancient pyramids were built, the precision of the stone cutting, and their placement in alignment with the stars. Pyramids Cultures around the world have built pyramids. Egypt is very well known for its pyramids including the Great Pyramids of Giza near Cairo. Ancient pyramids are also found in Greece, Rome, Guatemala, Sudan, Iraq, and Mexico. The Egyptians built pyramids because the ancient pharaohs were considered to be chosen by the gods to act as the connections between humans and the gods. The Egyptians considered the pharaoh to be the god Horus and responsible for protecting the sun god Ra. This connection to the gods made it very important to maintain the pharaoh s majesty, even after death. This was important because the pharaoh was thought to become Osiris, the god of the dead, after he died. The ancient Egyptians believed that part of the dead person s spirit, called the ka, remained in the body after death. They felt it was important to properly care for the ka, so they mummified their dead, including their pharaohs, and buried them with everything they might need in the afterlife. The Great Pyramids of Giza The Great Pyramids of Giza is a complex of the best-known great pyramids in the world and includes the Sphinx. In fact, the Great Pyramid of Giza, also called the Khufu Pyramid after is occupant, is the oldest of the Ancient Seven Wonders of the World and the only one still standing. The pyramids in this complex were built as burial sites for the Khufu (Cheops), his three wives, relatives, and the officials who served the pharaoh. The Great Pyramid of Giza was the tallest structure in the world for almost 4,000 years. By Daniel Mayer (Own work) [GFDL ( fdl.html) or CC BY-SA ( org/licenses/by-sa/ )], via Wikimedia Commons. [403]

2 Arts Anywhere The World of STEAM [404] Statistics about the Great Pyramid of Giza Construction period Estimated number of Construction Workers 20,000 Block setting speed Original Height Base Dimensions Base Area Angle of Sides Area of Each Side Number of Levels from Base to Top Volume of Pyramid Angle of Corners on Blocks Number of Limestone Blocks Weight of Limestone Blocks Weight of Granite Blocks Weight of Pyramid Alignment with Stars Building the pyramids BCE (23 years) 1 every 2.5 minutes, 7 days a week, for 23 years 481 feet 756 feet on a side 13 acres 51 degrees, 51 minutes 5.5 acres 203 levels 2.7 million cubic yards 90 degrees 2.3 million 2-15 tons each tons each 6.5 million tons Aligned with magnetic north The pyramids have lasted for thousands of years. How did the people of that time build such durable structures? Well, there are a lot of theories ranging from slaves to aliens. The truth is that Egyptian citizens built the pyramids. One of the big challenges was mining and placing the stones required to build the pyramids. Workers cut blocks of stone from nearby quarries using iron and copper tools. Dolerite pounding stones were used to quarry granite stones. The workers used an early version of the modern crane to lift the stones from the quarry. A wooden levering tower sitting on the top edge of the quarry allows the workers to lift the stones from the pit and swing them over to the ground outside the quarry. These are big stones, so the workers had to devise a way to move the stones from the quarry to the build site. They used barges for water transport and wooden sleds to move the stones over land. Sometimes the workers used animals to pull the sleds and other times they pulled the sleds themselves. Before the stones were pulled across the ground, the workers smoothed the roads/paths and sometimes even used lubricant on the road to make it easier to pull the loads. Another big challenge is to move the stone blocks into the correct place in the pyramid. Each stone weighed several thousand pounds, so the workers built earthen ramps around the pyramids in order to move the stones into place.

3 Workers may have used lifting devices called shadoofs to move smaller stones from the ground to the lower levels of the pyramid. A shadoof is a simple crane that consists of 2 poles that hold a long pole that is tied to a fulcrum. The workers could use a team of men, counterweights and a shadoof to move large stones with relative ease. Workers also had to move the large stones to the upper levels of the pyramid as it grew. One approach the ancient Egyptians might have used is the counter-weight counter-ramp principle. The men pull a large stone up a shallow ramp, which may be covered in logs that roll as the stone passes over it, by walking down a steep staircase as they pull the rope over a smooth pole. The pole allows the rope to move smoothly and increases the downward angle of the rope, making it easier to move the stone up the ramp. It is possible to build in a braking system by placing flat board over the rollers. If the boards are placed so they overlap about half their lengths, the boards create a notch where they overlap. This creates a relatively smooth surface for pulling the stone up the ramp, and provides a safeguard by acting like a ratchet system that catches the stone rather than letting it slide to the bottom of the ramp. This works fine at the lower levels, but becomes more challenging as the pyramid gets taller and narrower. There is less room to work at the top of the pyramid. No one knows how the workers solved this problem, but there are several theories: A long, gentle earthen ramp was built along the sides of the pyramid. A steep earthen staircase ramp was built along the sides of the pyramid. An earthen ramp was built that spirals around the pyramid. Stones near the top of the pyramids may have been placed using levers or modified ramps instead of extending the entire ramp. Precise stone placement There is no written record of how the stones were placed, but there are some theories. The stones can be moved close to where they need to be placed using rollers, battering rams and levers. The battering ram and levers then allow the workers to move the stone off the last roller and use the battering ram to place the stone precisely. Teams of men using battering rams could generate enough force to get the stones in just the right position. Workers used powdered gypsum to lubricate the entire level (or course) of the pyramid before placing the next level of stones. The gypsum serves two purposes: it makes it easier to move the stones and also cements the stones in place. Again, teams of men use a battering ram to push the stones into place. In fact, teams of 20 men are able to swing a battering ram that weights 500 kg (1100 lbs.) like a pendulum. They allow the pendulum to build up momentum until it hits a five-ton stone. When the ram hits the stone, it generates enough [405]

4 Arts Anywhere The World of STEAM acoustic and mechanical energy to shift the stone without using rollers. Each hit moves the stone slightly, so the stone can be placed very precisely. If the stone weighed 10 tons, 2 teams of 20 men would use battering rams to move it into place. Simply add a team of 20 men with a 500 kg ram for each 5-tons of stone. Finishing the pyramid The sides of an Egyptian pyramid are smooth. When the last stone is place at the top of a pyramid, the pyramid is stepped, meaning it has an uneven outline. Egyptian pyramids are smooth because they are finished from the top down. The workers shaped and placed white limestone to create the smooth surface on each side of the pyramid. They would take the ramp apart as they finished each level, until they finally reached the ground. The alignment of the pyramids with the stars The pyramids of the Great Pyramids of Giza are aligned with the stars as they were at the time the pyramids were built. The Great Pyramid of Giza, for example, contains four shafts that extend from the King and Queen chambers inside the pyramid toward the stars. They are aligned due north and due south. They are also aimed at specific stars that would have been present in the sky about 2500 BCE. The Orion-Giza Alignment Theory describes the alignment of the three primary pyramids at Giza (including the Great Pyramid) with the three stars in the belt of the Constellation Orion. Chamber North or South Shaft King s Northern 32 degrees, 28 minutes King s Southern 45 degrees, 14 minutes Queen s Northern 39 degrees, 0 minutes Angle Name of Star Importance to Ancient Egyptians Theban (Alpha Draconis) Al Nitak (Zeta Orionis) Kochab (Beta Ursa Minor) Cosmic pregnancy and gestation Osiris, the Egyption high god of resurrection and rebirth and who became the constellation Orion after he died Cosmic regeneration and the immortality of the soul Queen s Southern 39 degrees, 30 minutes Sothis (Alpha Canis Major) Isis, the cosmic mother of the kings of Egypt [406]

5 Astronomical discoveries of the ancient Egyptians 365-day calendar As early as 3000 BCE Precessionary cycle of the equinoxes The amount of time it takes the stars to appear to completely rotate around the Earth. This cycle is 25,920 years long. The Khufu calendar Uses the shadows of the three smaller pyramids next to the Great Pyramid of Giza. Used to identify the solstices and equinoxes each year. The Cycle of Sothis Does not include a leap year. The time it takes the Egyptian 365-day year to cycle completely through all of the seasons. 1,460 years long (365 days x 4 seasons). The rising of Sothis (modern-day Sirius) with the Sun predicts when the Nile will flood the capitol of Egypt (Memphis). LESSON QUESTIONS 1. How were the ancient Egyptian pyramids built? Describe the ways the stones were moved up to each level of the pyramid. 2. How were the stones of the pyramid so precisely placed? 3. Describe how the Great Pyramid of Giza was aligned with the stars at the time it was built in 2500 BCE. [407]

6 Arts Anywhere The World of STEAM ANSWERS 1. How were the ancient Egyptian pyramids built? Describe the ways the stones were moved up to each level of the pyramid. Each stone weighed several thousand pounds, so the workers built earthen ramps around the pyramids in order to move the stones into place. Workers may have used lifting devices called shadoofs to move smaller stones from the ground to the lower levels of the pyramid. A shadoof is a simple crane that consists of 2 poles that hold a long pole that is tied to a fulcrum. The workers could use a team of men, counterweights and a shadoof to move large stones with relative ease. Workers also had to move the large stones to the upper levels of the pyramid as it grew. One approach the ancient Egyptians might have used is the counterweight counter-ramp principle. The men pull a large stone up a shallow ramp, which may be covered in logs that roll as the stone passes over it, by walking down a steep staircase as they pull the rope over a smooth pole. The pole allows the rope to move smoothly and increases the downward angle of the rope, making it easier to move the stone up the ramp. It is possible to build in a braking system by placing flat board over the rollers. If the boards are placed so they overlap about half their lengths, the boards create a notch where they overlap. This creates a relatively smooth surface for pulling the stone up the ramp, and provides a safeguard by acting like a ratchet system that catches the stone rather than letting it slide to the bottom of the ramp. This works fine at the lower levels, but becomes more challenging as the pyramid gets taller and narrower. There is less room to work at the top of the pyramid. No one knows how the workers solved this problem, but there are several theories: A long, gentle earthen ramp was built along the sides of the pyramid. A steep earthen staircase ramp was built along the sides of the pyramid. An earthen ramp was built that spirals around the pyramid. Stones near the top of the pyramids may have been placed using levers or modified ramps instead of extending the entire ramp. [408]

7 2. How were the stones of the pyramid so precisely placed? There is no written record of how the stones were placed, but there are some theories. The stones can be moved close to where they need to be placed using rollers, battering rams and levers. The battering ram and levers then allow the workers to move the stone off the last roller and use the battering ram to place the stone precisely. Teams of men using battering rams could generate enough force to get the stones in just the right position. Workers used powdered gypsum to lubricate the entire level (or course) of the pyramid before placing the next level of stones. The gypsum serves two purposes: it makes it easier to move the stones and also cements the stones in place. Again, teams of men use a battering ram to push the stones into place. In fact, teams of 20 men are able to swing a battering ram that weights 500 kg (1100 lbs.) like a pendulum. They allow the pendulum to build up momentum until it hits a five-ton stone. When the ram hits the stone, it generates enough acoustic and mechanical energy to shift the stone without using rollers. Each hit moves the stone slightly, so the stone can be placed very precisely. If the stone weighed 10 tons, 2 teams of 20 men would use battering rams to move it into place. Simply add a team of 20 men with a 500 kg ram for each 5-tons of stone. 3. Describe how the Great Pyramid of Giza was aligned with the stars at the time it was built in 2500 BCE. The pyramids of the Great Pyramids of Giza are aligned with the stars as they were at the time the pyramids were built. The Great Pyramid of Giza, for example, contains four shafts that extend from the King and Queen chambers inside the pyramid toward the stars. They are aligned due north and due south. They are also aimed at specific stars that would have been present in the sky about 2500 BCE. The Orion-Giza Alignment Theory describes the alignment of the three primary pyramids at Giza (including the Great Pyramid) with the three stars in the belt of the Constellation Orion. [409]