The Valley of the Kings, the Pyramids of Giza; architectural marvels all. The big question that has plagued many historians and archaeologists is how an ancient civilization, without the means of modern mechanical technology, were able to transport megalithic structures and stone blocks weighing more than 2.5 tons through the desert. Present day research might now have the answer – the use of water to reduce friction and reduce the workforce required.

Research conducted by Daniel Bonn, from the University of Amsterdam, tested the sliding friction of dry and wet sand by pulling a weighted sled across the surface in a tray. With dry sand, a heap would form in front of the sled, hindering its movement. When adding water, both the force needed to pull the sled and the amount of friction decreased. As the water made the sand more rigid, the heaps got smaller and smaller until there was no obstacle forming in front of the moving sled. 

As a result of these experiments, it was revealed that the required pulling force decreased proportional to the stiffness of the sand. When water was added, capillary bridges arose; these small water droplets act like glue to bind the sand grains together. With the right amount of water, wet desert sand is about twice as stiff as dry sand, allowing the sled to glide far more easily.

Bonn wrote: 

“I was very surprised by the amount the pulling force could be reduced -- by as much as 50 percent -- meaning that the Egyptians needed only half the men to pull over wet sand as compared to dry.” 

Despite the scientific experimentation, evidence has existed in the form of a wall painting from the tomb of Djehutihotep, as seen below. In the encraving there is depicted a worker pouring water on the sand in front of a sled fully laden with a colossal statue. The sleds were little more than large wooden planks with upturned edges. Originally, “Egyptologists had been interpreting the water as part of a purification ritual and had never sought a scientific explanation.” 



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