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Ancient Egypt: Difference between revisions
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** first pyramid built in 751 BC at El Kurru, a royal cemetery | ** first pyramid built in 751 BC at El Kurru, a royal cemetery | ||
** emulated ancient Egyptian pharaonic practices | ** emulated ancient Egyptian pharaonic practices | ||
=== Pyramid building & engineering === | |||
[[File:Great Pyramid of Giza edge.jpg|500px|thumb|right|Great Pyramid of Giza edge: Average core blocks of the Great Pyramid weigh about 1.5 tons each, and the granite blocks used to roof the burial chambers are estimated to weigh up to 80 tons each. (wiki)]] | |||
* materials | |||
** Old Kingdom pyramids were built of stone | |||
*** early Old Kingdom pyramids were made entirely of limestone with gates, ceilings and walls of burial chambers and the outer casing made of high-quality limestone or granite | |||
*** the Great Pyramids are Old Kingdom constructions | |||
** Middle Kingdom pyramids | |||
*** Middle Kingdom pyramids were built of piled mud-bricks covered with limestone | |||
*** later pyramids were built on hills to reduce the amount of brick and stone required | |||
* construction | |||
** Ancient Egyptians were expert rope builders | |||
*** they understood the utility of tension and leverage | |||
*** they understood that an incline, or a ramp, spreads the force required to lift a heavy object across the distance of the incline | |||
<div class="mw-collapsible mw-collapsed" style="width:50%"> | |||
An inclined plane, also known as a ramp, is a flat supporting surface tilted at an angle, with one end higher than the other, used as an aid for raising or lowering a load.[1][2][3] The inclined plane is one of the six classical simple machines defined by Renaissance scientists. Inclined planes are widely used to move heavy loads over vertical obstacles; examples vary from a ramp used to load goods into a truck, to a person walking up a pedestrian ramp, to an automobile or railroad train climbing a grade.[3] | |||
Moving an object up an inclined plane requires less force than lifting it straight up, at a cost of an increase in the distance moved.[4] The mechanical advantage of an inclined plane, the factor by which the force is reduced, is equal to the ratio of the length of the sloped surface to the height it spans. Due to conservation of energy, the same amount of mechanical energy (work) is required to lift a given object by a given vertical distance, disregarding losses from friction, but the inclined plane allows the same work to be done with a smaller force exerted over a greater distance.[5][6] | |||
* Source: [[https://en.wikipedia.org/wiki/Inclined_plane Inclined Plane (wiki)]] | |||
</div> | |||
* '''click EXPAND for exerpt from wikipedia entry on how an incline helps to life heavy objects''' | |||
* sources | * sources | ||
** [http://en.wikipedia.org/wiki/Fourth_dynasty_of_Egypt 4th Dynasty] (wikipedia) | ** [http://en.wikipedia.org/wiki/Fourth_dynasty_of_Egypt 4th Dynasty] (wikipedia) | ||