Page 25 - Curriculum Visions Dynamic Book

igneous rock: a rock that has solidified from molten rock, either volcanic lava on the Earth’s surface or magma deep underground. In either case the rock develops a network of interlocking crystals.
metamorphic rock: formed either from igneous or sedimentary rocks, by heat and/or pressure. Metamorphic rocks form deep inside mountains during periods of mountain building. They result from the remelting of rocks during which process crystals are able to grow. Metamorphic rocks often show signs of banding and partial melting.
polymerisation: a chemical reaction in which large number of similar molecules arrange themselves into large molecules, usually long chains. This process usually happens when there is a suitable catalyst present. For example, ethene reacts
to form polythene in the presence of certain catalysts.
 A chain silicate.
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