California Science Content Standards

Transcription

1 California Science Content Standards Focus on Earth Sciences PLATE TECTONICS AND EARTH S STRUCTURE 6.1 Plate tectonics accounts for important features of Earth s surface and major geologic events. As a basis for understanding this concept: a. Students know evidence of plate tectonics is derived from the fit of the continents; the location of earthquakes, volcanoes, and midocean ridges; and the distribution of fossils, rock types, and ancient climatic zones. b. Students know Earth is composed of several layers: a cold, brittle lithosphere; a hot, convecting mantle; and a dense, metallic core. c. Students know lithospheric plates the size of continents and oceans move at rates of centimeters per year in response to movements in the mantle. d. Students know that earthquakes are sudden motions along breaks in the crust called faults and that volcanoes and fissures are locations where magma reaches the surface. e. Students know major geologic events, such as earthquakes, volcanic eruptions, and mountain building, result from plate motions. f. Students know how to explain major features of California geology (including mountains, faults, volcanoes) in terms of plate tectonics. g. Students know how to determine the epicenter of an earthquake and know that the effects of an earthquake on any region vary, depending on the size of the earthquake, the distance of the region from the epicenter, the local geology, and the type of construction in the region. SHAPING EARTH S SURFACE 6.2 Topography is reshaped by the weathering of rock and soil and by the transportation and deposition of sediment. As a basis for understanding this concept: a. Students know water running downhill is the dominant process in shaping the landscape, including California s landscape. b. Students know rivers and streams are dynamic systems that erode, transport sediment, change course, and flood their banks in natural and recurring patterns. c. Students know beaches are dynamic systems in which the sand is supplied by rivers and moved along the coast by the action of waves. d. Students know earthquakes, volcanic eruptions, landslides, and floods change human and wildlife habitats. HEAT (THERMAL ENERGY) (PHYSICAL SCIENCES) 6.3 Heat moves in a predictable flow from warmer objects to cooler objects until all the objects are at the same temperature. As a basis for understanding this concept: a. Students know energy can be carried from one place to another by heat flow or by waves, including water, light and sound waves, or by moving objects. b. Students know that when fuel is consumed, most of the energy released becomes heat energy. c. Students know heat flows in solids by conduction (which involves no flow of matter) and in fluids by conduction and by convection (which involves flow of matter). d. Students know heat energy is also transferred between objects by radiation (radiation can travel through space). ENERGY IN THE EARTH SYSTEM 6.4 Many phenomena on Earth s surface are affected by the transfer of energy through radiation and convection currents. As a basis for understanding this concept: a. Students know the sun is the major source of energy for phenomena on Earth s surface; it powers winds, ocean currents, and the water cycle. b. Students know solar energy reaches Earth through radiation, mostly in the form of visible light. viii STANDARDS REVIEW AND PRACTICE

2 REVIEW STANDARD 6.1.a Evidence of Plate Tectonics STANDARD Students know evidence of plate tectonics is derived from the fit of the continents; the location of earthquakes, volcanoes, and midocean ridges; and the distribution of fossils, rock types, and ancient climatic zones. STANDARD SET 1 Read the summary and map to answer the questions on the next page. Fit of the Continents The theory of plate tectonics states that Earth s surface consists of huge, moving slabs of rock called tectonic plates. The theory helps explain how major features of Earth s surface have formed and changed over time. The theory builds upon the continental drift hypothesis of German scientist Alfred Wegener. He proposed that the continents formed one huge landmass millions of years ago, but they split apart and slowly moved into their present positions. Support for this idea comes from the fact that the edges of the continents, especially South America and Africa, roughly fit together. HOW SOUTH AMERICA AND AFRICA FIT TOGETHER SOUTH AMERICA AFRICA Fossils, Rock Types, and Ancient Climates The geographic distribution of fossils, rock types, and ancient climates also supports the idea that the continents have changed their positions. For example, scientists have discovered the fossils of an ancient reptile named Mesosaurus in South America and western Africa but nowhere else in the world. In addition, the type of rock in Brazil matches the rock in western Africa. Scientists also have evidence that some tropical regions were once covered with ice sheets, and some lands in cold regions once had tropical climates. All these facts point to vast movements of the Earth s landmasses over millions of years. Location of Earthquakes, Volcanoes, and Midocean Ridges The present-day location of earthquakes, volcanoes, and midocean ridges (mountain ranges on the ocean floor) also supports the theory of plate tectonics. As tectonic plates move and shift position, they affect other plates nearby. As a result, most major earthquakes, volcanoes, and mountain ranges appear along plate boundaries. For example, many earthquakes occur in California along the San Andreas Fault, where the North American Plate and the Pacific Plate meet. Areas in which Mesosaurus fossils have been found STANDARDS REVIEW AND PRACTICE 1

3 PRACTICE STANDARD SET 1 STANDARD 6.1.a DIRECTIONS: Choose the letter of the best answer. 1 According to the theory of plate tectonics, Earth s surface consists of Evidence of Plate Tectonics 4 Matching fossils and rock types on continents that are separated by ocean today supports the idea that A one huge landmass. B huge, moving slabs of rock. C continents that have fixed positions. D continents that form plates. 2 The theory of plate tectonics helps explain why the coastlines of certain continents A seem to fit together. B change with erosion. C do not change. D suffer from hurricanes. 3 Most major earthquakes, volcanoes, and mountain ranges occur A along the edges of continents. B in North and South America. C where tectonic plates meet. D in the middle of tectonic plates. A all the continents of the world are basically the same. B islands once linked all the continents. C all the continents arose in their present positions at the same time. D the continents were formerly joined and moved apart. 5 Which statement best explains why Greenland, which is ice covered and located in the Arctic region, has fossils of tropical plants? A Greenland was once located in the tropics and had a tropical climate. B Birds carried plant seeds from the tropics to Greenland. C All of Earth once had a tropical climate. D Ocean currents carried the fossils to Greenland. 2 STANDARDS REVIEW AND PRACTICE

4 REVIEW STANDARD 6.1.b Earth s Layers STANDARD Students know Earth is composed of several layers: a cold brittle lithosphere; a hot, convecting mantle; and a dense, metallic core. STANDARD SET 1 Read the summary, chart, and visual to answer the questions on the next page. Earth s interior consists of three main layers: crust, mantle, and core. The core has two parts: an outer core and an inner core. With increasing depth, the temperature, pressure, and density in these layers increases. Layer Description Thickness Temperature Crust Mantle Outer core thin layer of cool rock thick layer of hot rock layer of hot, liquid metal 6 70 km varies 2900 km ºC 2300 km ºC Inner core ball of hot, solid metals 2400 km ºC Earth s crust is thicker on the continents and thinner under the ocean floor. Earth s crust and upper mantle form a rigid shell called the lithosphere. The lithosphere is broken up into the tectonic plates. The lithosphere rides on a layer of hotter, soft mantle rock called the asthenosphere. Like hot tar, the rock of the asthenosphere flows slowly. Thus, the plates of the lithosphere can slowly move on this layer of hot, soft rock. The thin, rigid crust (6 70 km thick) surrounds Earth. Lower pressure allows the outer core (about 2300 km thick) to remain liquid. The mantle (about 2900 km thick) is less dense near the crust, more dense near the core. CRUST AND MANTLE LAYERS less dense materials rise dense materials sink Intense pressure makes the inner core a solid ball about 2400 km in diamter. Ocean crust (about 7 km thick) forms the ocean floors. The lithosphere is made up of the crust and very top of the mantle. Continental crust (about km thick) makes up the continents. The asthenosphere is a hotter, softer layer of rock on which the lithosphere rests. STANDARDS REVIEW AND PRACTICE 3

5 PRACTICE STANDARD SET 1 1 The thin layer of cool rock that makes up Earth s surface is called the A core. B mantle. C crust. D asthenosphere. STANDARD 6.1.b 2 In Earth s interior, which of the following increase(s) with increasing depth? Earth s Layers DIRECTIONS: Choose the letter of the best answer. 4 The mantle is a layer of A hot rock between the crust and the core. B liquid metal between the crust and the core. C cool rock that covers Earth s surface. D soft metal between the inner and outer core. 5 The lithosphere consists of A temperature B pressure C density A the outer and inner core. B the crust and upper mantle. C the crust and the entire mantle. D all of the above 3 Earth s inner core consists of A solid metals. B liquid metals. C soft, tarlike rock. D cool rock. D the crust, mantle, and core. 6 The asthenosphere is a layer of A hard rock in the core. B hard rock in the mantle. C hot, soft rock in the crust. D hot, soft rock in the mantle. 4 STANDARDS REVIEW AND PRACTICE

6 REVIEW STANDARD 6.1.c Plate Movement STANDARD Students know lithospheric plates the size of continents and oceans move at rates of centimeters per year in response to movements in the mantle. Read the summary and diagram to answer the questions on the next page. STANDARD SET 1 How Rock in the Mantle Moves Inside Earth, heat is distributed unevenly. The deeper you go, the hotter it gets. In the asthenosphere, heat is transferred from lower depths to higher by the movement of rock, a process called convection. Hot rock is less dense, and so it rises. Cool rock is more dense, and so it sinks. Within the asthenosphere, hot rock rises. It cools down as it transfers heat to the surrounding rock. Cool rock is more dense, and so it sinks. It then heats up and rises again. This repeated rising and sinking motion is called a convection current. How Convection Affects the Tectonic Plates The tectonic plates, also called lithospheric plates, sit on the asthenosphere. The plates are huge, and most contain both continental and ocean crust. The convection currents in the asthenosphere drag the enormous plates along, moving them just centimeters a year. Over million of years, this slow movement has resulted in the lithospheric plates traveling thousands of kilometers. STANDARDS REVIEW AND PRACTICE 5

7 PRACTICE STANDARD SET 1 1 Convection is the transfer of A electric charge. B chemical energy. C steam. D heat. STANDARD 6.1.c 2 What happens in a convection current? A A hot material rises, cools, and sinks. B A cool material rises, heats up, and sinks. C A dense material sinks until it comes to a rest. D A dense material rises and then begins to sink. 3 What causes the movement of the lithospheric plates? A the flow of liquid rock in the asthenosphere B friction between the lithosphere and asthenosphere C convection currents in the asthenosphere D convection currents in the inner core Plate Movement DIRECTIONS: Choose the letter of the best answer. 4 How much do the lithospheric plates move in one year? A a few centimeters B a few kilometers C thousands of centimeters D thousands of kilometers 5 How much do the lithospheric plates move over millions of years? A a few centimeters B a few kilometers C thousands of centimeters D thousands of kilometers 6 STANDARDS REVIEW AND PRACTICE

8 REVIEW STANDARD 6.1.d Earthquakes and Volcanoes STANDARD Students know that earthquakes are sudden motions along breaks in the crust called faults and that volcanoes and fissures are locations where magma reaches the surface. STANDARD SET 1 Read the summaries and diagram to answer the questions on the next page. Earthquakes The convection of hot rock in Earth s mantle affects Earth s surface. This movement causes the lithospheric plates to move, which exerts force on the rock along plate boundaries. When the stress becomes too great, the rock breaks, producing a large break called a fault. Most, but not all, faults occur along plate boundaries. So do most earthquakes. An earthquake is a vibration of the ground caused by the sudden slippage of large blocks of rock along a fault. The energy released in an earthquake travels as seismic waves through and around Earth. Volcanoes Plate boundaries are also the sites of the majority of active volcanoes. A volcano is an opening through which magma (molten rock), gases, and rock fragments erupt. (Magma that reaches Earth s surface is called lava.) Mountains formed from volcanic eruptions are also called volcanoes. A crack in the ground or on the slope of a volcano through which lava flows is called a fissure. There are three main types of volcanoes: shield, cinder cone, and composite. STANDARDS REVIEW AND PRACTICE 7

9 PRACTICE STANDARD SET 1 STANDARD 6.1.d DIRECTIONS: Choose the letter of the best answer. 1 A large break in Earth s crust along which rock moves is called Earthquakes and Volcanoes 4 Magma reaches Earth s surface through a volcano and is then called A lava. B magma. C a fault. D a seismic wave. A lava. B cinder cone. C composite. D a fault. 2 Earthquakes are caused by 5 A shield volcano is A seismic waves that travel through Earth. B sudden movement of blocks of rock along faults. C magma pushing up through a crustal opening. D the buildup of volcanic materials. 3 Which of the following usually occur along plate boundaries? A faults B earthquakes C volcanoes D all of the above A steep and formed from rock fragments. B broad and flat and formed from rock fragments. C cone-shaped and formed from layers of lava. D broad and flat and formed from layers of lava. 6 A composite volcano is A cone-shaped and formed from layers of lava and of rock fragments. B cone-shaped and formed from rock fragments. C broad and flat and formed from layers of lava. D broad and flat and formed from layers of lava and of rock fragments. 8 STANDARDS REVIEW AND PRACTICE

10 REVIEW STANDARD 6.1.e Results of Plate Motion STANDARD Students know major geologic events, such as earthquakes, volcanic eruptions, and mountain building, result from plate motions. Read the summary and map to answer questions on the next page. STANDARD SET 1 Boundaries Between Plates At their boundaries, tectonic plates may spread apart, collide, or slide past each other. Divergent Boundaries Plates spread apart at divergent boundaries. Small earthquakes and mild volcanic eruptions are common at these boundaries. Convergent Boundaries Plates collide at convergent boundaries. If two plates with continental crust collide, the rock between them crumples and folds, forming folded mountains. If a plate with ocean crust collides with another plate with ocean crust, one plate sinks under the other, in a process called subduction. If a plate with ocean crust collides with a plate with continental crust, the plate with ocean crust sinks under the other. In such subduction zones, strong earthquakes and explosive volcanic eruptions occur, and volcanic mountain ranges develop. Transform Boundaries Plates slide past each other at transform boundaries. Here, strong earthquakes but almost no volcanic eruptions occur. Ring of Fire The Ring of Fire is a belt around the Pacific Ocean where most of the world s active volcanoes are concentrated. Most major earthquakes also occur in this belt. The belt follows much of the boundary of the Pacific Plate. ASIA INDIAN OCEAN AUSTRALIA PACIFIC OCEAN Equator PACIFIC OCEAN Ring of fire Active volcanoes Subduction zone NORTH AMERICA ATLANTIC OCEAN SOUTH AMERICA STANDARDS REVIEW AND PRACTICE 9

11 PRACTICE STANDARD SET 1 STANDARD 6.1.e DIRECTIONS: Choose the letter of the best answer. 1 Earthquakes occur at A divergent boundaries only. B convergent boundaries only. C transform boundaries only. D all types of plate boundaries. 2 Explosive volcanic eruptions and strong earthquakes often occur at A divergent boundaries. Results of Plate Motion 4 Where is the Ring of Fire located? A around the perimeter of the Indian Ocean B around the perimeter of the Arctic Ocean C around the perimeter of the Pacific Ocean D around the perimeter of the Atlantic Ocean B subduction zones. C transform boundaries. D all types of plate boundaries. 3 Which of the following are common along the Ring of Fire? A earthquakes B active volcanoes C mountain ranges D all of the above 5 Where do folded mountains form? A at convergent boundaries where two plates with continental crust collide B at divergent boundaries where two plates with continental crust collide C at convergent boundaries where two plates with oceanic crust collide D at divergent boundaries where two plates with oceanic crust collide 10 STANDARDS REVIEW AND PRACTICE

12 REVIEW STANDARD 6.1.f STANDARD Students know how to explain major features of California geology (including mountains, faults, volcanoes) in terms of plate tectonics. Read the map to answer questions on the next page. California Geology STANDARD SET 1 PLATE TECTONICS SHAPES CALIFORNIA STANDARDS REVIEW AND PRACTICE 11

13 PRACTICE STANDARD SET 1 1 Which two major lithospheric plates have a boundary that cuts across California, producing the San Andreas Fault? A Nazca and Eurasian B North American and South American C North American and Pacific D Indian and Australian 2 At what kind of plate boundary does the San Andreas Fault occur? A divergent B convergent C transform D subduction STANDARD 6.1.f 3 The Sierra Nevada is a fault-block mountain range, which formed when A earthquakes moved blocks of rock. B volcanoes erupted repeatedly. C rock folds as plates collided. D magma erupted as plates moved apart. California Geology DIRECTIONS: Choose the letter of the best answer. 4 What process primarily formed the Coast Ranges? A the movement of large blocks of rocks by repeated earthquakes B folding of the sea floor along the edge of the North American Plate C a series of volcanoes that are still active D the spreading of the Pacific Plate and the North American Plate 5 The Central Valley is a downward fold in the A San Andreas Fault. B Juan de Fuca Plate. C Pacific Plate. D North American Plate. 6 What kind of mountains are the Cascades? A volcanic B folded C fault-block D subducted 12 STANDARDS REVIEW AND PRACTICE

14 REVIEW STANDARD 6.1.g Earthquake Effects STANDARD Students know how to determine the epicenter of an earthquake and know that the effects of an earthquake on any region vary, depending on the size of the earthquake, the distance of the region from the epicenter, the local geology, and the type of construction in the region. STANDARD SET 1 Read the summary to answer questions on the next page. Many factors influence the effects of an earthquake on a region. These factors include the location of the focus and epicenter, the magnitude of the earthquake, the type of soil in a region, and the type of construction in a region. Location of Focus and Epicenter The focus of an earthquake is the underground point where the rocks first move. An earthquake with a deep focus usually causes less damage than one with a shallow focus because the seismic waves lose more energy as they travel a longer distance to Earth s surface. The epicenter of an earthquake is the point on Earth s surface directly above the focus. Scientists determine the epicenter of an earthquake by measuring the arrival times of seismic waves at a minimum of three recording stations. In general, the farther a region is from the epicenter, the less damage it will suffer. Magnitude of Earthquake The term magnitude refers to the strength of an earthquake, or the amount of energy it releases. The more energy an earthquake releases, the greater the ground movement. Scientists have developed a number of scales for reporting the magnitude of an earthquake, including the Richter scale and the moment magnitude scale. An increase of one whole number on these scales indicates an increase of 32 times more energy. The higher the magnitude, the greater the damage an earthquake can cause. Type of Soil and Construction Earthquake damage can vary depending on the type of soil underneath buildings. In areas with loose, wet sand and silt, ground shaking can cause the soil to act like a liquid. Buildings then sink into the soil or flow away with it. Earthquakes damage buildings made of brittle materials, such as brick, concrete, or adobe, more easily than buildings made of a flexible material such as wood. In addition, small buildings that are not firmly attached to their foundations may slide off their foundations in an earthquake. STANDARDS REVIEW AND PRACTICE 13

15 PRACTICE STANDARD SET 1 1 The point on Earth s surface directly above the underground point where the rocks first move in an earthquake is called the A focus. B epicenter. C magnitude. D seismic wave. 2 Scientists determine the epicenter of an earthquake by measuring A the arrival time of seismic waves at a minimum of three recording stations. B its magnitude on the Richter scale. C its magnitude on the moment magnitude scale. D how much damage it causes in different areas. 3 The effects of an earthquake on a region depend on A the location of the focus and epicenter. B its magnitude. C the type of soil and construction in the region. D all of the above STANDARD 6.1.g Earthquake Effects DIRECTIONS: Choose the letter of the best answer. 4 In which of these situations would you expect the most earthquake damage? A An earthquake of magnitude 1 hits a city that lies 10 miles from the epicenter. B An earthquake of magnitude 1 hits a city that lies 5 miles from the epicenter. C An earthquake of magnitude 7 hits a city that lies 10 miles from the epicenter. D An earthquake of magnitude 7 hits a city that lies 5 miles from the epicenter. 5 In which of these situations would you expect the most earthquake damage if all the earthquakes had the same magnitude and all the cities were the same distance from the epicenter? A An earthquake with a shallow focus hits a city with many brick houses. B An earthquake with a deep focus hits a city with many brick houses. C An earthquake with a shallow focus hits a city with many wood-frame houses. D An earthquake with a deep focus hits a city with many wood-frame houses. 14 STANDARDS REVIEW AND PRACTICE

16 REVIEW STANDARD 6.2.a Water Shapes the Landscape STANDARD Students know water running downhill is the dominant process in shaping the landscape, including California s landscape. Read the summary to answer questions on the next page. Running water is the primary natural force that changes and shapes the landscape of California and most of the rest of Earth. Water affects landscape through weathering (the breakdown of rock into smaller particles) and erosion (the movement of weathered particles from one place to another). Running water helps build or sculpt many landforms, including eroded mountains, valleys, deltas, and floodplains. Weathering In mechanical weathering, rock is physically broken down into smaller pieces without any chemical change. Mechanical weathering can occur when water seeps into cracks in rock and then freezes and thaws. Water expands when it freezes, and so it enlarges holes in the rock. Repeated freezing and thawing breaks the rock into smaller pieces. In chemical weathering, rock is changed into new compounds through chemical reactions. Rainwater can react with the minerals in rock to produce smaller particles of new compounds. Erosion Water running down sloping land picks up and carries along particles of weathered rock and soil, which are called sediment. Over millions of years, this erosion can wear down mountains. When the sediment is deposited in lowland areas, it builds up valleys. As water flows down a slope, it collects in channels and eventually runs into a river. Some of the sediment the river carries settles on the river s bottom, and some sediment is transported to the sea. As a river empties into the ocean, the water slows down and drops a large amount of sediment, forming an area of land called a delta. When a river in a lowland area floods, it may deposit large amounts of sediment on the land along its banks, called a floodplain. In this way, it may build up a valley with very fertile soil. STANDARD SET 2 STANDARDS REVIEW AND PRACTICE 15

17 PRACTICE STANDARD 6.2.a Water Shapes the Landscape DIRECTIONS: Choose the letter of the best answer. 1 The major natural force shaping the landscape over most of Earth, including California, is 4 Water moves weathered particles from one place to another in a process called A flooding. A mechanical weathering. B weathering. B chemical weathering. STANDARD SET 2 C water running downhill. D volcanic activity. 2 The process by which rock is broken down into smaller particles without any chemical change is called A mechanical erosion. B mechanical weathering. C chemical erosion. D chemical weathering. 3 As a river empties into the ocean and drops sediment, it builds up a A delta. B canyon. C mountain. D floodplain. C delta formation. D erosion. 5 Which of the following landforms are created by moving water? A eroded mountains B floodplains C deltas D all of the above 16 STANDARDS REVIEW AND PRACTICE

18 REVIEW STANDARD 6.2.b Streams Are Dynamic Systems STANDARD Students know rivers and streams are dynamic systems that erode, transport sediment, change course, and flood their banks in natural and recurring patterns. Read the summary to answer questions on the next page. The word dynamic can mean full of energy, continually moving, or continually changing. All three meanings apply to a stream, which is any body of water that flows down a slope along a channel. A river is a large stream, often with smaller streams draining into it. Streams Erode Rock and Transport Sediment. Water flowing down a slope carries sediment into a stream. The moving water of a stream also erodes the rock and soil along the banks of its channel. The sediment that a stream carries can hit solid rock with enough force to grind away the rock. In this way, streams in high mountains can cut deep channels through rock, forming steep canyons. In lower areas, streams may erode wide valleys. The erosive power of a stream depends on how fast it flows. In general, streams that have a steep slope and high volume of water flow faster and can cause more erosion. Streams Change Course. As a stream flows through a wide, flat valley or floodplain, its channel may form looping bends called meanders. The water flows faster along the outside bank of a meander, and so erodes that bank. The stream moves this sediment downstream and deposits it along inside banks of meanders. In this way, the meanders shift position over time. Eventually, a stream may erode a new channel segment that bypasses a meander. This shorter segment is called a cutoff, and the former meander becomes a curved lake called an oxbow lake. Streams Flood in a Natural Cycle. The volume of water in a stream naturally varies with the seasons. During times of heavy rain or when snow melts, a stream may overflow its banks, or flood. During a flood, a stream may cut new paths through the land along parts of its course. Flooding and redirection of course are part of a stream s natural, recurring cycle. STANDARD SET 2 STANDARDS REVIEW AND PRACTICE 17

19 PRACTICE STANDARD 6.2.b Streams Are Dynamic Systems DIRECTIONS: Choose the letter of the best answer. 1 Streams are dynamic because they 4 Oxbow lakes typically form in STANDARD SET 2 A do not vary from season to season or year to year. B have always existed and always will. C have energy and continually move and change. D have established channels through which they flow. 2 A stream that has a steep slope and a high volume of water typically A moves fast and causes much erosion. B moves fast and produces little erosion. C carries very little sediment. D forms many meanders. 3 An oxbow lake forms when a stream A deposits sediment along its outside bank. B cuts a new path that bypasses a meander. C changes direction and starts flowing upstream. D cuts a deep channel in a mountain. A mountains. B floodplains. C canyons. D deserts. 5 Flooding and changing course are A signs that a stream needs to be dammed. B caused solely by damming a stream. C abnormal events in a stream s cycle. D part of a stream s natural cycle. 18 STANDARDS REVIEW AND PRACTICE

20 REVIEW STANDARD 6.2.c Beaches Are Dynamic Systems STANDARD Students know beaches are dynamic systems in which the sand is supplied by rivers and moved along the coast by the action of waves. Read the summary to answer questions on the next page. Beaches are dynamic because they are continually moving and changing. A beach can be compared to a stream. Like the water in a stream, the sand that makes up a beach is continually on the move. Beaches form and change in several ways described below. Sand Comes from Rivers and Waves. Rivers carry sediment to the sea and drop some of it near the shore. Waves beating against nearby coastal land produce sediment. The two sources of sediment mix. STANDARD SET 2 Waves and Wind Shape and Change Beaches. Waves and currents move sediment along a shore, building up beaches. In longshore drift, angled waves cause a zigzag movement of sand along a beach. Angled waves also produce longshore currents, which move sand in the surf zone. Longshore drift and longshore currents can cause a beach to grow larger at one location and to slowly disappear at another. Strong storms can erode beaches and sometimes wash them away entirely. Wind can build up mounds of sand called dunes along a beach. Different Environments Produce Different Types of Sand. Sand from different beaches can vary in size, color, shape, and composition. These variations result from differences in local sources of sediment, the kind of weathering process, and the degree of weathering. STANDARDS REVIEW AND PRACTICE 19

21 PRACTICE STANDARD 6.2.c Beaches Are Dynamic Systems DIRECTIONS: Choose the letter of the best answer. STANDARD SET 2 1 Beaches are dynamic because they A do not vary from year to year. B provide stable sites for homes. C continually move and change. D always continue to get bigger. 2 Where does the sand that forms a beach come from? A sediment from rivers and coastal erosion B weathering of rock at the site of the beach C the bottom of the ocean D sediment carried by the wind from deserts 3 Most coastal beaches are formed by A the flooding of coastal rivers. B strong winds that carry mounds of sand. C strong storms that carry sediment from the bottom of the ocean. D waves and currents moving sediment along a shore. 4 In longshore drift, angled waves cause A sand to move farther into a beach. B sand to build up into huge dunes. C a zigzag movement of sand along a beach. D sand to move out into the open ocean. 5 As a result of longshore drift and longshore currents, beaches along a coast may A expand at one site and shrink at another. B develop huge dunes. C expand far out into the ocean. D shrink in every direction. 6 Why might sand at one beach be creamy white and sand at another beach be almost black? A differences in the amount of wind at the two locations B differences in local sources of sediment C differences in local sunlight D differences in the amount of salt in the ocean water 20 STANDARDS REVIEW AND PRACTICE

22 REVIEW STANDARD 6.2.d Natural Disasters Change Habitats STANDARD Students know earthquakes, volcanic eruptions, landslides, and floods change human and wildlife habitats. Read the summary and chart to answer questions on the next page. Natural disasters can greatly change the places where animals and plants live, which are called habitats. The immediate effects of natural disasters are usually negative. All natural disasters can cause a loss of lives, for example. Because of the negative effects, people should consider the frequency and severity of natural disasters in an area before deciding to build and live there. All natural disasters are part of Earth s natural processes, however, and they often have some positive long-term effects. EFFECTS OF NATURAL DISASTERS ON HABITATS Natural Disaster Negative Effects Positive Effects Earthquakes Volcanic Eruptions Landslides Floods damage buildings or cause collapse of buildings uproot trees cause fires from broken naturalgas and electric lines trigger landslides and sea waves called tsunamis bury habitats and structures under lava or volcanic ash ignite fires trigger mudflows and landslides pollute the air with toxic gases; this pollution also causes changes in the weather carry away plants, animals, and buildings bury habitats and structures bury or wash away habitats damage buildings help shape the landscape help scientists learn about the structure of Earth s interior bring new rocks and minerals to Earth s surface form new, rich soil build beautiful mountain landscapes help create valleys and other landforms cover the land with rich soil provide new habitats for plants and animals STANDARD SET 2 STANDARDS REVIEW AND PRACTICE 21

23 PRACTICE STANDARD 6.2.d Natural Disasters Change Habitats DIRECTIONS: Choose the letter of the best answer. STANDARD SET 2 1 Both earthquakes and volcanic eruptions can cause A changes in the weather. B fires and landslides. C air pollution. D the formation of rich soil. 2 Which of the following natural disasters often result in human and wildlife habitats being carried away or buried? 4 Which type of natural disaster helps scientists learn about Earth s interior? A floods B earthquakes C landslides D fires 5 Which type of natural disaster brings new rocks and minerals to Earth s surface? A landslides B volcanic eruptions A volcanic eruptions B floods C floods D all of the above 3 What is a positive effect of both volcanic eruptions and floods? A formation of beautiful mountains B tsunamis C formation of new, rich soil D mudflows and landslides C landslides D all of the above 6 Earthquakes, volcanic eruptions, landslides, and floods all play a role in A shaping the landscape. B changing habitats. C moving rocks and soil. D all of the above 22 STANDARDS REVIEW AND PRACTICE

24 REVIEW STANDARD 6.3.a Energy Is Transferred in Many Ways STANDARD Students know energy can be carried from one place to another by heat flow or by waves, including water, light and sound waves, or by moving objects. Read the chart to answer questions on the next page. HOW ENERGY IS CARRIED FROM ONE PLACE TO ANOTHER Heat flow Heat flow is a transfer of energy from a warmer object to a cooler object. Warming your hands on a mug of hot cocoa is an example of heat flow. Heat moves from the cocoa to the mug and then to your hands. Waves A wave is a disturbance that carries energy (but not matter) from one place to another. Other waves can travel through a vacuum, or empty space. In ocean waves, energy from the wind travels through the water. The water moves up and down but does not move forward with the energy. Light from the Sun travels to Earth in the form of electromagnetic waves. These waves move through empty space. Sound energy moves in waves through solids, liquids, and gases. The sound waves produced by a vibrating object can move through the air and cause another object, such as a person s eardrum, to vibrate. Moving Objects An object in motion has mechanical energy. The moving object can transfer energy to another object that it strikes. When a pitcher throws a baseball, energy moves from the pitcher s arm and hand to the baseball. STANDARD SET 3 STANDARDS REVIEW AND PRACTICE 23

25 PRACTICE STANDARD 6.3.a Energy Is Transferred in Many Ways DIRECTIONS: Choose the letter of the best answer. 1 The transfer of energy from a warmer object to a cooler object is called 4 Which of the following kinds of energy is carried by electromagnetic waves? A an electromagnetic wave. A light energy B mechanical energy. B sound energy C a wave. C mechanical energy D heat flow. D chemical energy STANDARD SET 3 2 A disturbance that carries energy from one place to another is called A a moving object. B mechanical energy. C a wave. D heat flow. 3 Which of the following situations illustrates heat flow? A throwing a basketball through a hoop B sitting by a fire to warm one s body on a cold winter night C creating ripples in the water by dropping a rock in a pond D listening to a musician play a guitar 5 Which of the following situations illustrates the transfer of energy by a moving object? A light from the Sun reaching Earth B heating a pot on a stove C listening to a concert D kicking a soccer ball 6 A wave carries A energy, but not matter. B matter, but not energy. C both energy and matter. D neither energy nor matter. 24 STANDARDS REVIEW AND PRACTICE

26 REVIEW STANDARD 6.3.b Burning Fuel Produces Heat Energy STANDARD Students know that when fuel is consumed, most of the energy released becomes heat energy. Read the summary and flow chart to answer questions on the next page. Fuel and Energy A fuel is a substance that is consumed to produce energy. Energy is the ability to cause change. The main types of energy include sound, mechanical, light, and chemical. Fossil fuels, such as coal, oil and natural gas are burned or consumed in power plants to produce electric current. Gasoline is burned in engines to produce mechanical energy, or the energy of motion. The energy of electric current is used to produce light. Sometimes these fuels are used to produce heat energy as their main product. But even when they are used to produce other forms of energy, heat energy is always produced as well. Matter is made up of atoms held together in molecules. The energy that holds the atoms together is chemical energy. When the molecules break apart, this chemical energy is released. Like other forms of matter, fuels contain chemical energy. When a fuel is burned, the chemical energy is released and changes form, producing heat and light. Energy Conversions: The Car as an Example The flow chart shows how energy changes form when gasoline is burned in a car. Although the energy changes form, the total amount of energy stays the same. Heat energy changes into mechanical energy. Gasoline burns in a car s engine, producing hot gases. The expanding hot gases set the car s parts in motion. When the brakes are applied, the car stops. Chemical energy changes into heat energy. Friction causes mechanical energy to change into heat energy. STANDARD SET 3 Most of the chemical energy released by the burning fuel eventually becomes heat energy. STANDARDS REVIEW AND PRACTICE 25

27 PRACTICE STANDARD 6.3.b Burning Fuel Produces Heat Energy DIRECTIONS: Choose the letter of the best answer. 1 The energy that holds atoms together in molecules is called 4 The friction that results from applying a car s brakes causes STANDARD SET 3 A chemical energy. B heat energy. C mechanical energy. D light energy. 2 What happens when a fuel is burned? A Mechanical energy is released, which produces heat energy. B Chemical energy is released and changes form, producing heat and light. C Heat energy is released and changes into mechanical energy. D Most of the energy is lost. 3 What kind of change in energy occurs when expanding hot gases set a car s parts in motion? A Light energy changes into mechanical energy. B Mechanical energy changes into chemical energy. C Chemical energy changes into heat energy. D Heat energy changes into mechanical energy. A heat energy to change into mechanical energy. B mechanical energy to change into heat energy. C chemical energy to change into heat energy. D chemical energy to change into mechanical energy. 5 What happens to most of the chemical energy released by burning fuel in a car? A It eventually becomes heat energy. B It eventually becomes mechanical energy. C It eventually becomes light energy. D It eventually becomes sound energy. 26 STANDARDS REVIEW AND PRACTICE

28 REVIEW STANDARD 6.3.c Heat Flow in Solids and Fluids STANDARD Students know heat flows in solids by conduction (which involves no flow of matter) and in fluids by conduction and by convection (which involves flow of matter). Read the summary to answer questions on the next page. Heat flow is the movement of heat energy from a warmer object to a cooler object. Two ways in which heat energy can be transferred are conduction and convection. Conduction Occurs Between Objects That Are in Contact. The atoms and molecules in any object, including a solid object, are always in motion. The particles in a warmer object move faster than those in a cooler object and so have a higher average energy of motion. When particles from the two objects collide, some of the energy from the warmer object is transferred to the cooler object. This process is called conduction. Conduction can only occur when two objects are touching. The objects can be solids, liquids, or gases. As long as two objects are touching, conduction continues until their temperatures are equal. Conduction can occur between two solids (a hot cup and your hands), between a solid and a fluid (your body in a warm tub of water), or between two fluids (hot oil poured into cold water). Convection Involves the Movement of Matter. Convection is the transfer of energy by the movement of a material. Convection only occurs in materials that can flow, or fluids. A fluid is a liquid or a gas. Most fluids expand when heated and so become less dense. Hot fluid is more buoyant and will rise through a cold fluid. The cold fluid sinks and replaces the rising hot fluid. As the cold fluid becomes heated, it also rises. In this way, a convection current becomes established, and heat gets transferred through the fluid. The process of convection can easily be observed in a pot of water heated on a stove. As the water at the bottom of the pot heats, it rises. Cool water replaces it at the bottom of the pan, gets heated, and rises. Because of the convection current, the water in the pot reaches a uniform temperature even though the pot is heated only at the bottom. STANDARD SET 3 STANDARDS REVIEW AND PRACTICE 27

29 PRACTICE STANDARD 6.3.c Heat Flow in Solids and Fluids DIRECTIONS: Choose the letter of the best answer. 1 Conduction only occurs between two objects that are 4 A convection current transfers heat energy as A fluids. B solids. C heated. D touching. A two objects touch and their particles collide. B a solid is placed in hot water. C hot water rises and cool water sinks. 2 What happens when the particles in a warmer object collide with the particles in a cooler object? A Energy is transferred from the warmer object to the cooler object. B Energy is transferred from the cooler object to the warmer object. D cool water rises and hot water sinks. 5 Convection only occurs in materials that A are liquids. B are solids. STANDARD SET 3 C Both objects lose energy. D Both objects gain energy. 3 Most fluids expand when heated and become A more dense and less buoyant. B less dense and more buoyant. C more dense and more buoyant. D less dense and less buoyant. C can flow. D are gases. 28 STANDARDS REVIEW AND PRACTICE

30 REVIEW STANDARD 6.3.d Transfer of Heat Energy by Radiation STANDARD Students know heat energy is also transferred between objects by radiation (radiation can travel through space). Read the summary to answer questions on the next page. All Objects Give Off Radiation. Conduction and convection are two of the ways that heat energy moves between objects. The third way is radiation, which is the process of energy traveling in electromagnetic waves. The energy of electromagnetic waves is partly electric and partly magnetic. The term radiation refers to both the process and the energy. All objects including light bulbs, people s bodies, plants, Earth, and the Sun give off radiation. Radiation travels in all directions from an object. Radiation Differs from Conduction and Convection. In conduction and convection, heat energy must travel through something. Radiation, however, can travel through empty space or through such materials as air and water. Radiation changes into heat energy when an object absorbs it. There Are Different Types of Radiation. The Sun s energy travels to Earth in the form of radiation, of which there are many types. Visible light is one type. Another type is infrared radiation, which people cannot see but can sense as heat. Infrared radiation is used to keep food warm. Many forms of radiation provide useful energy. Life on Earth depends on radiation from the Sun. Some forms of radiation, such as the ultraviolet rays that cause sunburn, can be harmful. STANDARD SET 3 STANDARDS REVIEW AND PRACTICE 29

31 PRACTICE STANDARD 6.3.d Transfer of Heat Energy by Radiation DIRECTIONS: Choose the letter of the best answer. 1 Energy that travels in electromagnetic waves is called A convection. B conduction. C radiation. D charged particles. 4 A person sitting under a lamp reading is warmed by the lamp. Heat energy is transferred to the person by A conduction. B convection. C radiation. 2 What is an important difference between radiation and the processes of conduction and convection? A Radiation is a natural process. B Radiation travels in more than one direction. D conduction, convection, and radiation. 5 Visible light and infrared radiation from the Sun A provide useful energy. B are harmful. STANDARD SET 3 C Radiation transfers heat energy. D Radiation can travel through empty space. 3 Radiation is given off by A all objects. B only the Sun. C only the Sun and Earth. D only large objects. C cannot be absorbed. D have no effect on Earth. 30 STANDARDS REVIEW AND PRACTICE

32 REVIEW STANDARD 6.4.a The Energy of the Sun STANDARD Students know the sun is the major source of energy for phenomena on Earth s surface; it powers winds, ocean currents, and the water cycle. Read the summary to answer questions on the next page. The Sun Supplies Energy for Living Things. The Sun is the main source of energy for life on Earth. Plants change sunlight into stored energy, and animals gain this energy when they eat plants. In this way, the Sun s energy feeds both plants and animals. The Sun Powers Winds and Ocean Currents. The Sun s energy travels to Earth as radiation. Earth s surface both land and water absorbs some of this radiation. The absorbed radiation changes into heat energy and warms the land, the oceans, and the air. Because of Earth s shape and tilt, solar energy does not heat all of Earth evenly. The amount of energy that strikes different parts of Earth varies with latitude, season, and time of day. This uneven heating of Earth s surface causes differences in air pressure from place to place. Warmer air rises, forming low-pressure areas. Cooler air sinks, forming high-pressure areas. Air moves from high-pressure areas to low-pressure areas. This horizontally moving air is wind. Global winds result from uneven heating between the equator and the north and south poles. Cold air from the poles moves toward the equator, and warm air from the equator moves toward the poles. As global winds blow over the oceans, they produce surface currents. These currents move warm water away from the equator and cold water away from the poles. Global winds and ocean currents circulate heat energy around Earth. The Sun Drives the Water Cycle. Energy from the Sun also drives the water cycle, in which water continually moves through Earth s environment. Solar energy warms the water in oceans, lakes, and streams. Some of the water evaporates, or turns into water vapor, and rises in the air. As the water vapor rises, it cools, condenses, and forms clouds. The water then falls back to Earth as rain or snow. The water cycle together with winds and ocean currents helps create climates and weather on Earth. STANDARD SET 4 STANDARDS REVIEW AND PRACTICE 31

33 PRACTICE STANDARD 6.4.a The Energy of the Sun DIRECTIONS: Choose the letter of the best answer. 1 The main source of energy for both plants and animals is the A Sun. B water cycle. 4 Global winds move warm air A from the poles toward the equator. B from north to south across the equator. C soil. D ocean. C from south to north across the equator. D from the equator toward the poles. STANDARD SET 4 2 What causes differences in air pressure from place to place? A the water cycle B currents in Earth s waters C uneven heating of Earth s surface D global winds 3 Wind is caused by air moving from A areas of low pressure to areas of high pressure. B areas of high pressure to areas of low pressure. C the upper atmosphere to the lower atmosphere. D the lower atmosphere to the upper atmosphere. 5 Surface currents in oceans result from A the water cycle. B global winds. C tropical storms. D changes in the weather. 6 Some of the water in oceans, lakes, and streams evaporates when it A is warmed by the Sun. B cools and forms clouds. C falls back to Earth as rain or snow. D turns into a liquid. 32 STANDARDS REVIEW AND PRACTICE

34 REVIEW STANDARD 6.4.b Solar Radiation STANDARD Students know solar energy reaches Earth through radiation, mostly in the form of visible light. Read the summary and diagram to answer questions on the next page. The Spectrum of Solar Radiation The Sun s energy reaches Earth as radiation, or energy that travels in electromagnetic waves. There are many types of radiation, including visible light, infrared light, microwaves, ultraviolet rays, and x-rays. Different types of radiation have different wavelengths. Wavelength is the distance from one crest to the next on a wave. The electromagnetic spectrum is the entire range of radiation from the shortest wavelength to the longest. The Sun gives off the full range of radiation in the electromagnetic spectrum. Visible light is only a small part of the whole spectrum. However, most of the solar energy that reaches Earth s surface is in this range. THE ELECTROMAGNETIC SPECTRUM The different forms of electromagnetic radiation vary in their wavelengths. wavelength visible light radio waves microwaves infrared ultraviolet x-rays gamma rays Absorption and Reflection of Solar Radiation All types of solar radiation reach the top of Earth s atmosphere, but only some of it passes through the atmosphere to reach Earth s surface. The gases in the atmosphere absorb some radiation and reflect some of it back into space. The atmosphere absorbs most electromagnetic radiation with wavelengths shorter than visible light, including x-rays and gamma rays. It also absorbs some types with longer wavelengths, such as infrared light and microwaves. The gases in Earth s atmosphere do not absorb visible light, so visible light passes through the atmosphere and reaches Earth s surface. In other words, the atmosphere is transparent to visible light. When visible light reaches Earth s surface, some of it is absorbed and some of it is reflected. STANDARD SET 4 STANDARDS REVIEW AND PRACTICE 33