Chapter 21- Planet Earth

2nd Semester Earth Science Ch 21- Planet Earth & Ch 22 Climate Chapter 21- Section 1: all; Section 2: p 709-710, 714 middle; 716-717; Section 3: all Chapter 22- Section 3 Climate 760-762Section 1: Earth’s Interior and Plate Tectonics What is Earth’s Interior Like? • The Earth is made up of three layers: the crust, the mantle and the core.• ______the thin and solid outermost layer of Earth above the mantle• ______the layer of rock between Earth’s crust and core• ______the center part of the Earth below the mantleStructure of the Earth DRAW AND LABEL your own diagram• Earth’s interior gets ______.• Geologists believe that the mantle is much hotter than the crust, reaching temperatures higher than 1250° C (2280° F).• The core is hotter than the mantle, reaching temperatures higher than 6000° C (10,800° F). • Radioactive elements contribute to Earth’s high internal temperature.• The breakdown of ______uranium, thorium and potassium ______that contributes to Earth’s ______.Plate Tectonics • Around 1915, German scientist Alfred Wegener proposed the idea that the continents were once united as a ______.• He pieced the continents together like a ______and called the supercontinent they formed ______.1 • Wegener found ______on widely separate continents, which supported his idea. • Evidence for Wegener’s ideas came later.• Wegener’s theory of continental drift was ignored until structures discovered on the ocean floor provided evidence for a mechanism for the movement of continents.• Symmetrical bands on either side of a mid-ocean ridge indicate that the two sides of the ridge were moving away from each other and new ocean floor was rising up between them. • ______supports the theory of moving plates. • Iron in molten rock aligns itself with Earth’s magnetic field as it cools.• The Earth’s magnetic field reverses polarity about every 200,000 years• The process is recorded as magnetic bands in rock, based on the age of the rock.• Symmetrical bands on either side of the Mid Atlantic Ridge suggest that the crust was moving away from the ridge. • Earth has ______that ______.• The crust and upper portion of the mantle are divided into about seven large pieces called ______.• ______the solid, outer layer of Earth, that consists of the ______and the rigid ______Plate tectonics the theory that explains how the outer parts of Earth ______, and that explains the relationships between ______, sea-floor spreading, ______, and volcanic activity• It is unknown exactly why tectonic plates move.• One hypothesis suggests that plate movement results from ______in the asthenosphere, the hot, fluid portion of the mantle.• Another hypothesis suggests that plate movement results from the ______acting on the plates.Plate Boundaries • Mid-ocean ridges result from ______. • The border between two plates is called a boundary.2 • Divergent boundary a place where two plates are ______• ______forms between divergent boundaries.• Magma ______produced under Earth’s surface• Oceanic plates ______continental plates at convergent boundaries. • Plates ______at a convergent boundary.• ______the process by which one lithospheric plate moves ______as a result of tectonic forces• The area where one plate slides over another is called a subduction zone. Subduction zones produce ______, ______, and ______.• Subduction of ocean crust generates ______.• Chains of volcanoes form on the upper plate in a subduction zone.• These volcanoes can form far inland from their associated oceanic trench.• Colliding tectonic plates create ______.• When two ______, mountains are formed at the boundary of the collision.• The ______formed during the collision between the continental tectonic plate containing India and the Eurasian continental plate.• Transform fault boundaries can ______.3 • Plate movement can cause ______.• ______a crack in Earth created when rocks on either side of a break move• Plate movement at transform fault boundaries is ______.Section 2 Earthquakes and Volcanoes What are Earthquakes? • Earthquakes ______.• Earthquakes are ______resulting from rocks ______each other at ______• Seismic waves are ______during an earthquake• Focus= the area along a fault at which the ______of an earthquake occurs• ______= the point on Earth’s surface directly above an earthquake’s focus• Energy from earthquakes is ______. • Earthquakes generate three types of waves: • ______• ______• ______• Longitudinal waves travel by ______and ______crust, also called primary waves (P waves) (SLINKY!)• Transverse waves travel in an ______movement, also called secondary waves (S waves)• Surface waves seismic waves that can ______, move in a ______motionDRAW! Longitudinal Wave Transverse Wave4 Volcanoes • A volcano is ______in Earth’s ______through which magma has reached Earth’s surface.• ______= an opening at the surface of Earth through which volcanic material passes• Volcanoes generally have one central vent, but they can also have several smaller vents. • Magma that reaches Earth’s surface is called ______.• Shield volcanoes have ______.• Lava from shield volcanoes is ______and forms a gently sloping mountain. • Shield volcanoes are some of the ______volcanoes.• Composite volcanoes have ______.• Composite volcanoes are made up of alternating layers of ash, cinders, and lava.• The lava is thicker than that of shield volcanoes.• Gases are trapped in the magma, causing eruptions that alternate between ______and ______that produces cinders and ash.• Composite volcanoes are typically ______.• Most volcanoes occur at ______boundaries. 5 • 75% of the active volcanoes on Earth are located in an area known as the ______.• The Ring of Fire is located along the edges of the ______, where ______tectonic plates are ______with ______plates.• Underwater volcanoes occur at ______plate boundaries.• As plates move apart at divergent boundaries, magma rises to fill the gap. • This magma creates the volcanic mountains that form ocean ridges.• ______is a volcanic island on the Mid-Atlantic ridge that is growing outward in opposite directions.• Volcanoes occur at ______. • Some volcanoes occur in the middle of plates.• ______are mushroom shaped trails of hot rock that rise from deep inside the mantle, melt as they rise, and erupt from volcanoes at hot spots at the surface.• The plumes remain in the same place as the tectonic plate moves, creating a trail of volcanoes.• The ______are an example of this type of volcanic activity.Section 3 Minerals and Rocks Structure and Origin of Rocks • All rocks are composed of ______.• There are about 3500 known minerals in Earth’s crust. • Each combination of rock-forming minerals results in a rock with a unique set of properties. • ______a natural, usually inorganic solid that has a characteristic chemical composition, an orderly internal structure, and a characteristic set of physical properties• Molten rock cools to form igneous rock.• Nearly all igneous rocks are made of crystals of various minerals.• ______rock that forms with magma cools and solidifies6 • Extrusive igneous rock cools _____ Earths surface• Intrusive igneous rock cools while ______Earth’s surface• Remains of older rocks and organisms form ______.• All rock breaks down over thousands of years.• ______the natural process by which atmospheric and environmental agents, such as ______, ______, and ______, disintegrate and ______rocks• As pieces of rock accumulate, they can form another type of rock.• ______a rock formed from compressed or cemented layers of sediment• Sediment= accumulated pieces of rock and other particles• Loose sediment forms rock in two ways.1. Layers of sediment ______from weight above, forming rock.2. ______seep between bits of sediment and “______” them together.• Sedimentary rocks are named according to the size of the fragments they contain.• Rocks that undergo pressure and heating without melting form ______rock.• Heat and pressure within Earth cause changes in the texture and mineral content of rocks.• Metamorphic rock= a rock that forms from other rocks as a result of intense ______, ______, or ______• ______rocks in the rock cycle form ______rocks.• The sequence of events in which rocks can be weathered, melted, altered, and formed is described by the ______.• Rock formation occurs ______, often over tens of thousands to millions of years.7 How Old Are Rocks? • The relative age of rocks can be determined using the ______. • The principle of superposition states the following: • Assuming no disturbance in the position of the rock layers, the ______will be on the ______, and the ______will be on ______. Law of Superposition• ______can determine a more exact, or ______, age of rocks. • The radioactive elements that make up minerals in rocks ______over billions of years. • Physicists have determined the ______at which these elements decay. • Geologists can use this data to determine the ______.8 CHAPTER 22 Section 3: Pages 760(climate) – 762 Climate • Climate the ______in an area over a ______of time.• Temperatures tend to be higher close to the ______.• Sunlight strikes the earth ______close to the equator. • The suns rays are less concentrated at ______, and do not warm the atmosphere as much.• Earth’s ______account for our ______. • When the North Pole is tilted toward the sun, the ______Hemisphere experiences ______.• When the South Pole is tilted toward the sun, the ______experience summer.• Summer solstice the ______of the year• Winter solstice the ______of the year• Vernal equinox the point in the ______when the ______are ______• Autumnal equinox the point in the ______when the ______are ______• Global climate changes over time. • Many factors produce changes in Earth’s climate, such as: • ______• slight changes in Earth’s ______• ______• changes in the ______• Earth’s climate is likely to continue changing over the millennia to come.9

Chapter 21- Planet Earth

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