One of the enduring mysteries of the pyramids - how ancient Egyptians managed to transport the huge stones used in their construction - may have been solved, with researchers discovering that simply adding water might have been enough. Blocks were known to have been dragged on sleds, but historians had always been uncertain as to how the Egyptian's workers avoided simply creating vast ridges of sand as the weight of the stones dug in.
Now, physicists at the FOM Foundation and the University of Amsterdam believe, just mixing the sand with water could have left things sufficiently stable to avoid that problem.
Lab testing discovered that, while dry sand was dredged up into ridges ahead of the sleds, when the right amount of water was added the desert would have been twice as stiff. Small water droplets bound the grains together, and when the correct balance is struck, the wet surface allows the sleds to slide across the top.
Ironically, the answer may have been in front of historians all the time. A wall painting from the tomb of Djehutihotep showed not only the sort of huge work crews involved in hauling the blocks out to the desert, but a person on the front carrying a jug and pouring out water.
While it addresses one Egyptian curiosity, the research may well have broader implications for construction today, too. The FOM team suggests that it could assist in the transportation and processing of modern day materials that are primarily found in granular form, such as concrete.