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Published byJanis Kelly Modified over 9 years ago
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Volcanoes
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Do Now 11/12/13 1.What is magma? 2.At which type of plate boundary are volcanoes most common? 3.Which mineral is the hardest? The softest? 4.What is the difference between a clastic sedimentary rock and an organic?
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Do Now 11/13/13 1.What is density? 2.How does density affect plate movement? 3.How does density affect the layers of the Earth? 4.How does density affect the formation of volcanoes?
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Do Now 11/12/13 1.When plates move together they form a ________________ boundary. 2.When plates move apart they form a ___________________ boundary. 3.When plates slide past each other they form a ____________ boundary. 4.The theory that plates were once joined in a supercontinent is called _______________.
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Do Now 12/3/12 1.Human Activity: The natural movement of sediment from one place to another is called _______. 2.Pollution: Water pollution is caused by __________. 3.Natural Resources: A natural resource that cannot be reused or replaced quickly. 4.Waves: The distance between the crest and trough of a wave is called the _________.
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1) What is a volcano? A mountain that forms when molten rock (magma) is forced to the Earth’s surface. Mt. Saint Helens, Washington Last Eruption 2008 Pavlof Volcano, Alaska Last Eruption 2007
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Active Volcanoes of the World
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2) What are the parts of a volcano? Magma Chamber –large underground pool of molten rock. Main Vent – where hot magma has reached the surface. Crater – a funnel shaped pit at the top of the volcano. Ash Cloud – gas and small pieces of pulverized rock.
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2) What are the parts of a volcano? Lava – Molten rock above the Earth’s surface. Pyroclastic Material – rock fragments, ash, gas released during eruption. Side Vent – secondary place where lava escapes the volcano.
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3) What are the three types of volcanoes? ShieldComposite Cinder Cone
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Shield Volcanoes Formed from runny lava and basalt Non explosive eruptions Gentle sloping sides Wide base Forms underwater
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Examples of Shield Volcanoes Hawaiian Islands
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Cinder Cone Volcanoes Made of pyroclastic material Explosive eruptions Steep sides Narrow base Found in clusters Erode quickly because there is no lava to cement rocks together
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Examples of Cinder Cone Volcanoes Paricutin - Mexico
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Composite Volcanoes Made from alternating layers of lava and pyroclastic material Non explosive and explosive eruptions Steep sides Wide base Also called Stratovolcano
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Example of Composite Volcano Mount Hood, Oregon
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4) What is a non explosive volcano? A volcano that produces lava flows.
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5) What is an explosive volcano? Volcanoes that blast out gas, rock, ashes/dust, and superheated steam.
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6) What determines if a volcano is explosive or non explosive? The composition of the magma determines what type of eruption. - Explosive volcanoes have more water and silica.
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7) What is a caldera? A circular depression that forms when a magma chamber empties and causes the ground above it to sink.
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