This term, we have been learning about rocks. We discovered that some rocks are natural, such as granite or limestone, and some are human-made, such as concrete. There are three main ways that natural rocks are fomed; these are sedimentary rocks, metamorphic rocks and igneous rocks. In one lesson, we tried to make a representation of sedimentary rock, by creating flakes of sediment that might have fallen from a cliff (represented by the clay) into the sea (represented by the blue paper). Over time, the sediment is pushed together, forming sedimentary rock. The grains are still visible. If the sedimentary rock then becomes heated by magma, along with the high pressure from the ocean above, the rock will be transformed into metamorphic rock. Igneous rock is made from cooled lava. It can form above the ground's surface, when a volcano erupts, or underground if the magma chamber doesn't reach the surface.