The Changing earth

Shows how the structure of the earth has been continuously changing from the start of geological time. The action of natural forces, heat, wind, rain and ice cause rocks to crumble, forming silt which is carried down into the ocean to form layers of sediment on the sea bed. Pressure of further layers deposited above, produces the rocks in which oil is slowly formed from the remains of the marine life. Animated diagrams show how the oil under pressure tends to migrate through the rocks, until it either finds its way through to the surface or is trapped in one of the formations for which oil-seekers look.