A scientific research institution proposed that wet sand was the key for the ancient Egyptians to carry huge stones and statues in the desert. The researchers pointed out that the ancient Egyptians put heavy stones on the sled, laid a layer of wet sand in front of the sled, and then dragged them. This transportation method had an unexpected effect. In the experiment, the researchers used a rheometer to test the hardness of sand, in order to confirm how much traction force is needed to deform a certain amount of sand. And on this basis, a traction model is designed. It is found that it is easier to move heavy objects when wet sand is laid before the skid, and the water content in the sand determines the hardness and traction force of the sand.
Skid traction is inversely proportional to the hardness of sand, which is twice as hard as dry sand, if true, best supports the above conclusion.