ancient egypt

By Korrey Laderoute 
The ancient Egyptians knew in their day what we have just discovered now; friction. The mystery of how the pyramids came to be created in ancient may finally be solved, thanks to physicists from the University of Amsterdam and the Foundation for Fundamental Research on Matter. They looked at the effort that would be required to pull heavy stones on an enormous sled-like pulley and found that moistening the ahead of the contraption made it easier to move. The scientists originally found clues to the discovery from artwork that was found in the tomb of Djehutihotep. The painting was discovered intact in deep shades of gold, brown, orange and gray with hieroglyphic markings on it, as well as a scene.

Workers pulling sled & pouring a liquid
 

 
The Victorian Era discovery dates back to 1900 B.C., and shows 172 able-bodied men lugging a huge stone statue of the Middle Kingdom Pharaoh on a sledge with ropes attached to it. A person can be seen at the front of the contraption showering the sand with water. Egyptologists had thought that the reason ancient Egyptians had done this was for ceremonial reasons, but had never scientifically explained it. There has been great analysis and dialogue over exactly what the person is doing with the water and why. Now, however, the mystery may be solved of how built the pyramids.

Researchers designed small-sized sledges and tried different ways of pulling them through sand. They found that when they pulled the sleds over the dry sand, the dirt piled up in front of the devices, creating berms in the sand and needing more effort to drag them. However, when they added water to it, the liquid made the surface stiffer, allowing the scientists to move the sledges easier. This is the key to the mystery of ancient Egypt built the Pyramids may be solved.

The droplets of water create bridge-like structures between the sand grains, allowing them to better fuse together. This is the very reason why building a sand castle with wet sand is better and easier. Keeping a perfect balance is key though; too much and the static friction gets weaker and weaker as more water is added to the equation, and to little creates berms in the sand that build up in front of the sled. The optimum amount depends on the sand, but is usually between 2 and five percent of the volume of material.

Apparently Egyptian sand is very good at reducing friction when it is wet. This makes it optimal for not needing a heavy workforce in order to move large materials a long way. The amount of force that is required to move extremely large objects could be cut in half and the threat of sand berms would virtually disappear. Experiments with the Egyptian sand showed that the needed force shrank in proportion to the sands rigidity, making it twice as firm as dry sand.
Researchers explain that this experiment not only solved the mystery of how ancient Egypt built the Pyramids, but also that sand stiffness is precisely linked to the friction force. The study may also have modern uses, such as understanding the ways of other granules. Knowing this may make the transport of other different types of granular materials like coal, concrete or asphalt more efficient.

Sources:Discovery NewsCBSNEWSThe Washington PostGIZMODO