A person is shown in the painting as standing on the sledge and wetting the sand in order to reduce the friction.
Besides being renowned for their great architecture, Egyptians left a great mystery behind them. The world is puzzled on how were they able to move those huge pyramid stones especially considering that some of them weighed up to several tons or more. A new research which was published in the journal Physical Review Letters now suggests that the pyramid stones were dragged over a wet sand. As part of the study researchers built a miniature version of the Egyptian sledge and put in it weights between 100 grams to few kilograms.
They then studied the force needed to pull the sledge under various condition: from dry sand to a very wet sand. The result of the study was as predicted: as water is added the sand becomes more rigid the heaps of sand that normally form in front of the object being pulled when trying to drag a sledge on dry sand will decrease in size and even disappear if the sand has the right amount of water. Too much water is also not good so the tick is to use the right amount of water in order not to hinder the movement of the sledge.
Scientists consider the wet sand hypothesis rather good but believe that wet sand was not the only thing being used to facilitate the transportation of large building blocks. Experiments showed that by using Tafla instead of sand building blocks can be supposed to adjustments and more precise movements. By using gypsum mortar, this is even finer than tafla, Egyptians might have been able to do even more precise adjustments.