Rocks and the Rock Cycle Image source: www.missouristateparks.net

Can you think of some places where rocks and minerals can be found? … and what about in cities or towns? Rocks and minerals are all around us. It takes millions of years for rocks to form - we must use our natural resources wisely. 1. Creek beds, river banks, road cuts and railroad cuts, excavation sites, cliffs, beaches 2. Rock walls and buildings, brick buildings (made of clay), concrete buildings/ foot paths (made from limestone), glass windows (glass is made of sand), steel structures (Steel is made from iron ore).

Three Types of Rocks IGNEOUS (Latin for fire) SEDIMENTARY (Latin for settle) METAMORPHIC (Greek for change) Igneous Latin for fire, sedimentary Latin for settle

Igneous Rocks Formed when magma (the molten rock that lies under the earth’s crust) is forced to higher layers of the crust – cools & solidifies. There are 2 types of igneous rocks – Intrusive & extrusive INTRUSIVE - Formed when magma slowly solidifies inside earth. Takes thousands of years to harden. Not seen until surface rocks have been eroded away. Coarse-grained. EXTRUSIVE – Formed when magma ERUPTS from volcanoes or escapes through cracks to form lava. Lava cools quickly – and forms into rocks. Fine-grained, e.g. Pumice and basalt. Intrusive rocks cool slowly underground. Extrusive rocks cool within a couple of weeks of reaching surface. http://www.youtube.com/user/Sciencebox2010#p/search/0/d4XAOY-VEEI

DEFINITION Igneous rock is a volcanic rock that forms when magma cools and hardens. Intrusive igneous rock solidifies underground. Extrusive igneous rock solidifies above ground. Igneous is Latin for fire Images source: www.geology.com

Igneous Rocks Volcanic eruption Earth’s Surface Igneous Rock Molten Rock Image source: www.bprc.osu.edu/ LET’S VIEW A VOLCANIC ERRUPTION!!! http://www.youtube.com/watch?v=s2i4XS0Esks&feature=related

Sedimentary Rocks Erosion --> rocks and minerals break down into small pieces called sediments. Carried by ‘the elements’ & deposited in river beds or sea beds. Accumulate (build-up) in layers --> pressed together by weight of new sediments. Compressed sediments are ‘cemented’ & harden to form new rock.

Sedimentary Rocks Have you ever noticed layers or bands in rocks? These are the layers of sediment. Examples: Sandstone, limestone, chalk and shale Fossils are often found in sedimentary rocks. Why do you think this might be?

DEFINITION Sedimentary rock is a rock formed near Earth’s surface from pieces of other rocks, plant or animal remains, or by the build-up of chemical solids. Latin for settle Images source: www.geology.com

Sedimentary Rocks Sea Land Weight and pressure of sediment particles Image source: www.bprc.osu.edu/ http://www.youtube.com/user/Sciencebox2010#p/search/0/9Df4CtlZ0AQ

Metamorphic Rocks Igneous and sedimentary rocks can be changed into a different kind of rock by extreme heat or pressure – the changed rock is called metamorphic rock. Original rock may be forced into new arrangements, sometimes new minerals form. Metamorphic rocks can also change again. Examples: Shale --> Slate Limestone --> Marble Granite --> Granite gneiss Sandstone --> Quartzite Changes in appearance or mineral composition

DEFINITION Metamorphic rock is a rock formed by the transformation of existing rock, as a result of extreme heat and/ or pressure. http://www.youtube.com/user/Sciencebox2010#p/search/0/ggIpPHIeJu4 Greek for change Images source: www.geology.com

Metamorphic Rocks Image source: www.bprc.osu.edu/ http://www.youtube.com/watch?v=G7AWGhQynTY&feature=related

The Rock Cycle Rock is constantly being changed by; heat, pressure, melting, crystallization, compaction, cementation and weathering. Move rock material through the states of; melts, igneous rock, sediments, sedimentary rock and metamorphic rock. This natural and ongoing cycle is known as the rock cycle. Animation of the rock cycle: www.youtube.com/watch?v=U7YQ5vwaL98&feature=related

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