How could the pharaohs transport such heavy pyramid stones

      For centuries, people have theorized how the great pyramids were built. Some have suggested that they must have been constructed by extraterrestrials, while others believe the Egyptians possessed a technology that has been lost through the ages.

                                   The Pyramids of Giza, built between 2589 and 2504 BC.

         Physicists from the FOM Foundation and the University of Amsterdam have discovered that the ancient Egyptians used a clever trick to make it easier to transport heavy pyramid stones by sledge. The Egyptians moistened the sand over which the sledge moved. By using the right quantity of water they could halve the number of workers needed. The researchers published this discovery online on 29 April 2014 in Physical Review Letters. 

      scientists investigated the forces needed to pull weighty objects on a giant sled over desert sand, and discovered that dampening the sand in front of the primitive device reduces friction on the sled, making it easier to operate. The findings help answer one of the most enduring historical mysteries: how the Egyptians were able to accomplish the seemingly impossible task of constructing the famous pyramids.

      Rheometer, which shows how much force is needed to deform a certain volume of sand.

Experiments revealed that the required pulling force decreased proportional to the stiffness of the sand. Capillary bridges arise when water is added to the sand. These are small water droplets that bind the sand grains together. In the presence of the correct quantity of water, wet desert sand is about twice as stiff as dry sand. A sledge glides far more easily over firm desert sand simply because the sand does not pile up in front of the sledge as it does in the case of dry sand.

A large statue is being transported by sledge. A person standing on the front of the sledge wets the sand. Source: Al-Ahram Weekly, 5-11 August 2004, issue 702. Credit: Fundamental Research on Matter (FOM)

                                                                                                By/ Ahmed Bakr