How to build a perfect sandcastle ?.. | Inventer le monde |
Ever wondered how they build those dramatic sandcastles on the beach? The trick is getting the perfect amount of water : only 1%. Less than that, and the sand will crumble under its own weight. More and it washes away. Physicist Daniel Bonn of the University of Amsterdam and his colleagues examined the scientific literature and found only one paper examining the physics of building sandcastles. That paper claimed that the stability of the structures is due to capillary rise of water through the sand and projects that the maximum height of a castle should be only 20 centimeters / 8 inches : an absurd conclusion to anyone who has ever visited the beach…

Daniel Bonn/University of Amsterdam :