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there are three types of rock igneous metamorphic sedimentary rocks
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igneous rocks are formed from molten rocks
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the two types of igneous rocks empezar lección
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the molten rock which erupts onto the Earth's surface is called lava. lava cools to form rocks with smaller crystals example basalt
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another type of igneous rock empezar lección
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the molten rock found under the Earth's surface is called magma. magma cools slowly to form rocks with larger crystals. example granite
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formed from other rocks as a result of volcanic action
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rocks which come into contact with magma are heated and changed to new rocks
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extreme pressure caused by tectonic movements can also alter rocks. example clay becomes slate
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the natural breakdown of rocks at the Earth's surface
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physical weathering happens when the weather breaks down rocks without altering them chemically
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freeze thaw weathring and onion skin weathering
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water seeps into cracks. temperature drops down below 0 degrees Celsius. water freezes and becomes ice. ice expands and creates pressure. pressure widens the crack.
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the high temperature heats the rock. surface of the rock expands. temperature drops down at night. rock contracts. the surface of the rock peels.
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it involves chemical reactions between rain water and rocks.
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biological weathering is the breakdown of rocks by plants animals and insects
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biological weathering by plants empezar lección
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roots from trees and plants grow into the crack. the root widens the crack and breaks it
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biological weathering by animals and insects empezar lección
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creatures that live underground helps to break up softer rocks just as clay
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wearing away the land by wind, river, ice, sea
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attrition, abartion, hydraulic action, plucking
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