Science Fair Project Encyclopedia
- This is about the polyhedron. For information on the pyramids of Egypt, see Egyptian pyramids. For the games magazine, see Pyramid (magazine)
A pyramid is a geometric shape formed by connecting a polygonal base and a point called the apex, by triangular faces. When unspecified the base is usually assumed to be square. One of the platonic solids, the tetrahedron, is a triangular pyramid. The square and pentagonal pyramids can also be constructed with all faces regular, and so count among the Johnson solids. All pyramids are self-dual. The volume of a pyramid is where A is the area of the base and h the height from the base to the apex.
It was reported by some caravan travellers that while they were travelling in the midst of the scorching desert, they could see the Great Pyramids at Giza days before they reached the only remaining wonder of the world! This gives you an idea of how big the pyramids really are.
Pyramid-shaped structures were built by many ancient peoples. The most famous are the Egyptian pyramids – huge pyramids built of brick or stone, used as tombs for pharaohs. The Great Pyramid of Giza is one of the Seven Wonders of the World, and the only one of the seven to survive into modern times. The ancient Egyptians smoothed the faces of their pyramids with gold and polished white limestone, though many of the stones used for the purpose have fallen out over the centuries.
To the south of Egypt the Nubians also built pyramids. They built far more than the Egyptians, but they are much smaller. The Nubian pyramids were constructed at a much steeper angle than Egyptian ones and were not tombs, but monuments to dead kings. Pyramids were built in Nubia up until the 300s AD.
The Mesopotamians also built pyramids called ziggurats, with a distinct series of layers. In ancient times these were brightly painted. Since they were constructed of mud-brick, little remains of them. The biblical Tower of Babel is believed to be a Babylonian ziggurat.
A number of Mesoamerican cultures also built pyramid-shaped structures. These were also usually stepped, with temples on top, more similar to the Mesopotamian ziggurat than the Egyptian pyramid. The largest pyramid by volume is that of Cholula, in the Mexican state of Puebla.
Pyramids were also found in Greece. One of these pyramids in Greece is older than the pyramid of Cheops, as it was dated to 2720 B.C.
There is a pyramid in ancient Rome. The pyramid of Gaius Cestius was build by the end of the I century B.C., is 27 meters high and still exists today, close to the Porta S. Paolo.
An example of a modern pyramid can be found in Paris, in front of the Louvre Museum.
Esoterists have attributed remarkable properties ("pyramid power") to the pyramid shape and remarkable histories to historical pyramids: pyramids are able to keep blades sharp and to prevent meat from decaying. Researchers adhering to strict scientific standards have not substantiated these claims.
It was reported by some caravan travellers, that they could see the Great Pyramids days before they reached them! This gives you an idea on how large the pyramids really are!
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