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Volcanoes – Day 2. Earth Science 10/7/10. Announcements. We will have a QUIZ tomorrow on Volcanoes! Vocabulary for Chapters 8 and 10 are due TOMORROW! Remember, this is the time to make a NEW start and get a good grade for this new report card!. Objectives.
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Volcanoes – Day 2 Earth Science 10/7/10
Announcements • We will have a QUIZ tomorrow on Volcanoes! • Vocabulary for Chapters 8 and 10 are due TOMORROW! • Remember, this is the time to make a NEW start and get a good grade for this new report card!
Objectives • I will be able to relate plate tectonics to volcanoes by describing ________________ __________________________, the types of boundaries that produce volcanoes. • I will be able to _____the locations of volcanoes on a map and compare patterns of volcanoes to plate tectonics.
Key Points • Magma composition plays a major part in determining the form of a volcano. • Magma forms when solid rock in the crust and upper mantle melts. • The composition of the material, water content and confining pressure are factors that affect the melting point of rock. • Magma tends to rise towards Earth’s surface primarily because rocks become less dense when they melt. • Most of the active volcanoes on Earth are located in a belt known as the ring of fire. • Identify an O-C plate boundary creating a volcano.
How Volcanoes Form • How Volcanoes Form Video
Magma • As we know, ________________plays a major part in determining the __________of a volcano. • But where does magma come from? • Magma forms when __________in the crust and upper mantle ________.
Magma • How does rock melt? • There are ________factors that contribute to rocks melting, or the formation of magma. • ________ • As you go ______in the earth, the temperature _____. • Subduction creates friction and causing heat • As magma ________, it heats rocks closer to the earth’s surface. • But this alone is ____________to create all of the magma that we know exists below the earth’s crust…
Magma • Confining ___________ • As confining pressure is __________, the melting temperature of rocks is ________. • This means that as rocks can __________as they are released from the confining pressure deep within the earth. • This process is called _____________________
Magma • __________Content • Water in rocks can cause a rock to melt at _________temperatures. • Rocks with more water in them melt easier than rocks that are “dry”. • BOTTOM LINE: The _____________ ________________, ________content and confining ________are factors that affect the __________________ of rock.
Magma • Now that we know how magma forms, why does it come to the surface of the planet? • Let’s discuss. • Write down what you think: __________________________________ __________________________________
Magma • Magma tends to rise towards Earth’s surface primarily because ______________________ ____________________________________. • What does that mean? When rocks change from a solid state to a liquid state, they become _____________! • What is lighter will rise, just like heavy things sink!
Plate Tectonics and Volcanoes • Most of the active volcanoes on Earth are located in a belt known as “____________”. • Others are located seemingly sporadically around the globe. • Scientists could not explain the worldwide distribution of volcanoes until the introduction of the theory of ___________________________.
The Ring of Fire • Watch a slideshow of the Volcanoes on the Ring of Fire HERE!
Plate Tectonics and Volcanoes • Plate movement forms volcanoes in three zones: • ___________Plates • Ocean – Ocean • Rising magma can form volcanic ________arcsin an ocean (Aleutian Islands). • Ocean – Continent • Rising magma can form __________volcanic arcs(Andes Mountains).
Convergent Boundary Volcano Was type of convergent boundary caused Mt. St. Helens? How do you know? Mount St. Helens emitting volcanic ash 2 months after it’s May eruption in 1980.
Plate Tectonics and Volcanoes • __________Plate Boundaries • When plates pull apart, there is less pressure on the rocks below. • Because of the ________________, rocks melt and magma is formed.
Plate Tectonics and Volcanoes • Intraplate Igneous Activity (non boundary) • Intraplate means activity _______a tectonic plate _______from plate boundaries. • This is caused by ________________. • Examples of this are the ____________________
Mapping Volcanoes Lab Follow the directions on the handout to map volcanoes around the world. After you finish plotting the volcanoes, answer the questions in complete sentences.
Check In – Answer on a separate piece of paper in COMPLETE sentences. • Most of the active volcanoes on Earth are located where? • Explain how magma forms. • What three things affect the melting point of a rock? • Why does magma rise to earth’s surface?