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Chapter 3 Section 1 The Geosphere The Earth as a System • Earth is divided into four parts: • The Geosphere • The Atmosphere • The Hydrosphere • The Biosphere Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 1 The Geosphere Discovering Earth’s Interior • Measure changes in the speed and direction of seismic waves through different mediums. • Earth is made up of different layers Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 1 The Geosphere The Structure of the Earth • Compositional Layers – Crust – Mantle – Core • Physical Layers: – Lithosphere - solid, outer layer of crust and upper mantle (tectonic plates). – Asthenosphere – “plastic” layer of mantle (flows allowing tectonic plates to move). – Mesosphere - lower mantle. – outer core - liquid layer – Inner core - center of the Earth, dense, solid, made of iron and nickel. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 1 The Geosphere Earth’s Layers Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 1 The Geosphere Plate Tectonics • The continents are located on tectonic plates • The major plates are – Pacific – North American – South American – African – Eurasian – Antarctic • Tectonic plates may separate/collide/slip past one another causing mountains, earthquakes, and volcanoes. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 1 The Geosphere Earthquakes • Fault- break in the Earth’s crust • When rocks under stress break along a fault, earthquakes are set off. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 1 The Geosphere Earthquakes • Magnitude-energy released by an earthquake. – smallest magnitude felt is 2.0 – largest magnitude recorded is 9.5 – Magnitudes >7.0 cause widespread damage. • An increase of 1 whole number releases 31.7x more energy. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 1 The Geosphere Earthquake Hazard • Scientists can determine where earthquakes are likely to occur, not when. • An area’s earthquake-hazard level is determined by past/present seismic activity. • Earthquake-resistant buildings are flexible so that they can sway with the ground motion. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 1 The Geosphere Volcanoes • Volcanoes are often located near colliding/separating tectonic plate boundaries. • Most active volcanoes are on Pacific Plate boundaries. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 1 The Geosphere Local Effect of Volcanic Eruptions • ash, dust, and gases can flow up to 200 km/hr and sear everything in their path. • volcanic ash can mix with water and produce mudflows. • ash can cause buildings to collapse, bury crops, damage car engines, and cause breathing difficulties. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 1 The Geosphere Global Effects of Volcanic Eruptions • In large eruptions, clouds of ash and gases spread across the planet reducing the amount of sunlight that reaches the Earth’s surface. • This can cause a drop in global temperature for several years. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 1 The Geosphere Erosion • Erosion – Earth’s materials are transported from one place to another by wind, water, ice or gravity. • Erosion wears downs rocks and makes them smoother over time. Older mountains are therefore smoother than younger ones. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 2 The Atmosphere The Atmosphere • Gases can be added and removed from the atmosphere through living organisms. • Volcanic eruptions add gases to the atmosphere, while vehicles both add and remove gases. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 2 The Atmosphere Composition of the Atmosphere • Nitrogen is 78% of the atmosphere (produced by volcanoes and decaying organisms). • Oxygen is 21% of the atmosphere (produced by plants). • Other gases include argon, carbon dioxide, methane, and water vapor. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 2 The Atmosphere Air Pressure • Earth’s atmosphere is pulled toward Earth’s surface by gravity, therefore, the atmosphere is denser near the Earth’s surface. • Air becomes less dense with elevation, so breathing at higher elevations is more difficult. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 2 The Atmosphere Layers of the Atmosphere • Four layers based on temperature changes above Earth’s surface. • Troposphere • Stratosphere • Mesosphere • Thermosphere Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 2 The Atmosphere The Troposphere • troposphere – lowest layer – temperature decreases as altitude increases. – weather conditions occur – densest layer Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 2 The Atmosphere The Stratosphere • Stratosphere – above the troposphere – Temperature rises as altitude increases because ozone in the stratosphere absorbs the sun’s UV energy and warms the air. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 2 The Atmosphere The Mesosphere • above the stratosphere • coldest layer (temperatures as low as –135ºF) Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 2 The Atmosphere The Thermosphere • farthest from Earth’s surface • nitrogen and oxygen absorb solar radiation resulting in temps above 3,632 ºF • air is so thin that air particles rarely collide, so little heat is transferred, and would therefore not feel hot. • X rays and gamma rays absorbed by nitrogen and oxygen cause atoms to become electrically charged ions. – lower thermosphere is called the ionosphere. – Ions can radiate energy as light, which glow as the Aurora Borealis near the poles. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 2 The Atmosphere Energy Transfer in the Atmosphere • Radiation – energy transferred as waves (sunlight) • Conduction - transfer energy as heat through contact • Convection - movement of matter due to differences in density caused by temperature variations – warm air rising and cool air sinking Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 2 The Atmosphere The Greenhouse Effect • The greenhouse effect - warming of the lower atmosphere that occurs when greenhouse gases absorb, trap, and reradiate infrared radiation. • Without the greenhouse effect, the Earth would be too cold for life to exist. • The most abundant greenhouse gases are water vapor, carbon dioxide, methane, and nitrous oxide. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 3 The Hydrosphere and Biosphere The Hydrosphere • The hydrosphere includes all of the water on Earth – oceans, lakes, rivers, wetlands, polar ice caps, groundwater, and clouds. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 3 The Hydrosphere and Biosphere The Water Cycle • water cycle - continuous movement of water – Evaporation –liquid to gas – Condensation –gas to liquid • Water vapor on dust particles form clouds. – Precipitation - rain, snow, sleet, and hail Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 3 The Hydrosphere and Biosphere Earth’s Ocean • The largest ocean is the Pacific • Deepest point, the Challenger Deep, in the Mariana Trench. – 11,033 m which is deeper than Mount Everest is tall • Surface currents move clockwise north of the equator. • Surface currents move counter-clockwise south of the equator. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 3 The Hydrosphere and Biosphere Earth’s Oceans • The 2nd largest ocean is the Atlantic – half the size of the Pacific – divided into a north and south half based on the surface current flow • The Indian Ocean is the 3rd largest ocean • The smallest ocean is the Artic – Mostly covered by floating ice Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 3 The Hydrosphere and Biosphere Ocean Water • Salinity is the amount of salt in a liquid. – Salinity is low in places high precipitation or where fresh water flows in to the sea. – Salinity is high where water evaporates rapidly and leaves the salt behind. • Most salt in the ocean is NaCl. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 3 The Hydrosphere and Biosphere Temperature Zones • The surface zone is warmed by the sun, while the deep zone is just above freezing. • Surface waters are mixed by waves/currents. • In the middle is the thermocline, where the temperature falls rapidly. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 3 The Hydrosphere and Biosphere A Global Temperature Regulator • The ocean absorbs and releases heat slower than land, so the temperature of the atmosphere changes slowly. • Without the ocean, temperatures would be too extreme for life to exist on Earth. • Currents that circulate warm water bring moderate climates to land. – EX: the British Isles are warmed by the waters of the Gulf Stream. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 3 The Hydrosphere and Biosphere Ocean Currents • Surface currents: Wind driven movement of water near the surface. • Deep currents - movements of water that flow slowly along the ocean floor. – form when cold, dense water from the poles sinks below warm, less dense water and flows toward the equator. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 3 The Hydrosphere and Biosphere Fresh Water and River Systems • Fresh water – most is locked in icecaps and glaciers, the rest is in lakes, rivers, wetlands, the soil and atmosphere. • river system - network of streams that drains an area of land. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 3 The Hydrosphere and Biosphere Ground water • Aquifer: A rock layer that stores groundwater. • Rain and melting snow sink into the ground, run off the land and collect as groundwater. • 1% of all the water on Earth, yet fulfills the need for drinking water, and supplies agricultural and industrial need. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 3 The Hydrosphere and Biosphere The Biosphere • biosphere -part of Earth where life exists (11 km into the ocean and 9 km into the atmosphere). • When an organism dies, its nutrients become available for other organisms. • Plants need sunlight to produce their food, and form the basis of the food chain. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved. Chapter 3 Section 3 The Hydrosphere and Biosphere Energy Flow in the Biosphere • Closed systems: Earth cannot exchange matter outside of its boundaries. • Open systems: Earth can exchange energy outside of its boundaries. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.