The intense temperature and strain separate the bitumen and water from the sand, and the bitumen - rendered soft with the heat - surfaces while the sand stays put. October 15: London's major water source, a pipeline that carries some 46 million gallons every single day, is severely damaged in a bombing raid. They consist of a mixture of roughly 90 % sand, water and clay and around 10 % bitumen - a heavy, viscous form of petroleum. It's petroleum that exists naturally in a solid or semisolid sta...