"[A team of eight researchers led by Daniel Bonn] placed a laboratory version of an Egyptian sledge in a bin of sand that had been dried in the oven. Then they threw down some water, and measured the grains’ stiffness."
Surely the way to test this theory isn't to make a model of a sledge, and bake some wet sand in an oven in your lab in Amsterdam! Go to Cairo, build a wooden sledge, get some water and fifty men for an hour and see whether one can sledge two tons across wet sand. I quite fancy testing it out myself. Perhaps I could run a Kickstarter to build a pyramid.
NOVA on PBS pulled a "Mythbusters" in the 1990s and made attempts to raise an obelisk using only technology & techniques conceivably available at the time:
I'm not sure I wouldn't rather explain to Egyptian vs American immigration officials that I wanted to go out into the desert with a bunch of people and "build an experimental..."
The picture is quite convincing indeed... once I was biased by the explanation!
For those of you that haven't read the article yet, I suggest you study the picture with the hieroglyphics in detail first and then read the conclusion!
Edit:
Just to be clear, I wanted others to have the benefit of seeing the picture before the explanation, because after the fact I had no idea whether I had been biased by what I had read first! I wasn't trying to suggest it was biased per se! I have no idea whether I was biased or not. I can't undo history.
OK, I did that. Still haven't read the article yet, actually. It looks like a statue on sled with a guy pouring something out in front of it. And having now read the article, it appears that's exactly the same conclusion it reaches.
I think it's quite convincing once you know the scientific fact that dragging an object requires half the work on wet sand. What's the alternative: that the Egyptians did at some point drag objects on wet sand, but that they didn't know it made things easier? Wouldn't they immediately learn that the first time they tried it, even if they first tried it for a different reason?
Maybe all that happened is that they tried picking up their work after some rain had fallen (this does happen, even there) and they found the work to go much easier. Then when it dried up again they found it got harder, so they re-created the conditions artificially.
I imagine many discoveries are made in this manner. I.e. accidental. Sometimes it can take centuries though for someone to see something obvious and realise its potential.
I love seeing how clever people figure out ways to solve problems with the tools they have. Also good to remember hacking didn't start with and doesn't only apply to computers.
If the water had the appropriate level of wetness, something called “capillary bridges” — extremely small droplets of water that glue together individual grains of sand — would form.
I wonder what happened when the water wasn't wet enough.
I like this part, in reference to a painting that shows water being poured on the sand in front of a sled:
>“In fact, Egyptologists had been interpreting the water as part of a purification ritual, and had never sought a scientific explanation. And friction is a terribly complicated problem; even if you realize that wet sand is harder – as in a sandcastle, you cannot build on dry sand — the consequences of that for friction are hard to predict.”
Makes me wonder what other practical things we might be misinterpreting as rituals. Are we constantly ignoring ancient cultures' innovations because we assume they have no practical purpose?
OK, but how did they move the water? I can't load the Uni page to see how much water was needed but if we're talking miles or tens of miles, we should be talking about a lot of water. Water that dries very quickly so the path has to be wet again for the next load.
I think that egyptians had access to irrigation technology. And from what I remember as a kid on the beach you don't need that much water - you only need to create a film.
A few ways come to mind - a channel from nile parallel to the hauling route. On the barge itself.
Although I would have used combination of highly polished wood, leather/hides on wood planks and cooking oil. And crews that just take the back pieces and move them in front.
Surely the way to test this theory isn't to make a model of a sledge, and bake some wet sand in an oven in your lab in Amsterdam! Go to Cairo, build a wooden sledge, get some water and fifty men for an hour and see whether one can sledge two tons across wet sand. I quite fancy testing it out myself. Perhaps I could run a Kickstarter to build a pyramid.