A Lesson From the Egyptians

As it turns out, egyptologists had the answer all the time, illustrated with a very nice picture, which they understandably misinterpreted. According to IFL Science, we now know how the Egyptians pulled those 5,000 pound stones and those huge statues on sleds across the desert sands to build the pyramids.

[N]ew research shows how adding a small amount of water to sand significantly reduces the sliding friction — a clever trick that allowed the Egyptians to cut the number of workers needed by half. . . . [In an experiment] [w]ith dry sand, a heap would form in front of the sled, hindering its movement. And as they added 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. Their experiments revealed that the required pulling force decreased proportional to the stiffness of the sand.

Anyone who’s pulled something along a beach immediately thinks “Well, yeah, of course.” But no one seems to have thought of this before in relation to the ancient Egyptians pulling things across the sand. Even though a wall painting shows someone pouring sand in front of a sled.

In a wall painting from the tomb of Djehutihotep (schematic above), you can see a worker pouring water on the sand in front of a sled that’s carrying a colossal statue. The sleds were little more than large wooden planks with upturned edges. “Egyptologists had been interpreting the water as part of a purification ritual,” Bonn says, “and had never sought a scientific explanation.”

It’s a useful lesson in the way our understanding advances and the ways it doesn’t. No one sees the answer, or rather everyone sees the answer what they think already suggests to them, and then suddenly someone sees the answer and everyone else “Oh, wow, right.”

If I were someone trying to explain an ancient civilization, I think my rule would be: Try to find the practical explanations first, and only if I can’t find one suggest the religious one. Religious people then were like religious people now. If they had a job to do, they did it.