According to a study, they poured small amounts of water on the sand to facilitate the sliding of the sleds.
Skilled Egyptian stonemasons carved the massive blocks of stone that were then transported up the Nile aboard large barges. They were then placed on sleds that hundreds of workers dragged to their final location.
But how they slid down the sand reducing the maximum frictional force and using the smallest possible number of workers?
A team of physicists, led by Daniel Bonn of the University of Amsterdam, believes they have found the solution.
“We show experimentally that sliding friction on sand is considerably reduced by adding some but not much water,” explain the researchers in a study published in the scientific journal Physical Review Letters.
A revealing wall painting
The team of physicists not only proved their hypothesis through a simple experiment, but also observed an Egyptian wall painting whose content is especially revealing.
It dates from 1880 BC and decorates one of the walls of the tomb of the nomarch Djehutihotep, in the necropolis of Deir El Bersha, in Middle Egypt.
In it dozens of workers appear dragging a sled carrying a colossal statue and a character on the front of the sled pours water on the sand, presumably to facilitate the transport of the statue.
According to the authors of the study, the Egyptians found that with the dry sand a mound formed in front of the sled that made it difficult to drag it, but in turn the excessive spilling of water decreased the hardness of the sand.
“More generally, frictional resistance in transport on sand is still a matter of debate. Our results demonstrate that the presence of even small amounts of water and polydispersity can change friction, and therefore flow behavior, significantly,” they conclude.