th's Crust 261791 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: Rocks in continental crust are as old as _____ years. Choice Feedback A. 44 million This is not old enough. B. 200 million This is the age of the oldest oceanic crust. *C. 4.4 billion That's correct! Global Incorrect Feedback The correct answer is: 4.4 billion -------------------------------------------------------------------------------- Question 1b of 10 ( 1 Earth's Crust 261803 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: Rocks in ocean crust are as old as _____ years. Choice Feedback A. 44 million B. 4.4 billion *C. 200 million Global Incorrect Feedback The correct answer is: 200 million. -------------------------------------------------------------------------------- Question 1c of 10 ( 1 Earth's Crust 261804 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: How does the age of the oldest continental crust compare to the age of the oldest ocean crust? Choice Feedback A. Continental crust is much younger. B. They are about the same age. *C. Continental crust is much older. Global Incorrect Feedback The correct answer is: Continental crust is much older. -------------------------------------------------------------------------------- Question 2a of 10 ( 2 Characteristics of Earth's Layers 165904 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: Which of Earth's layers is a liquid? Choice Feedback A. Crust The crust is solid. This is the layer we live on. B. Lower mantle The lower mantle is made of hard rock. *C. Outer core That's correct! D. Inner core The inner core is under such high pressure that it is a solid. Global Incorrect Feedback The correct answer is: Outer core. -------------------------------------------------------------------------------- Question 2b of 10 ( 2 Characteristics of Earth's Layers 261805 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: The only part of Earth's inner structure that is a liquid is the _____. Choice Feedback A. crust B. mantlemantle *C. outer core D. inner core Global Incorrect Feedback The correct answer is: outer core. -------------------------------------------------------------------------------- Question 2c of 10 ( 2 Characteristics of Earth's Layers 261806 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: Temperature and pressure combine to keep the outer core in a _____ state. Choice Feedback A. solid B. gaseous *C. liquid D. plasma Global Incorrect Feedback The correct answer is: liquid. -------------------------------------------------------------------------------- Question 3a of 10 ( 2 Characteristics of Earth's Layers 165905 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: Which of Earth's layers is the thinnest? Choice Feedback *A. Crust That's correct! B. Lower mantle That's not it. The lower mantle is much thicker than the crust. C. Upper mantle That's not it. The upper mantle is much thicker than the crust. D. Inner core That's not it. The inner core is much thicker than the crust. Global Incorrect Feedback The correct answer is: Crust. The crust is the thinnest layer. -------------------------------------------------------------------------------- Question 3b of 10 ( 2 Characteristics of Earth's Layers 261807 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: Which of Earth's layers is just below the crust? Choice Feedback *A. Upper mantle B. Lower mantle C. Outer core D. Inner core Global Incorrect Feedback The correct answer is: Upper mantle. The upper mantle is just below the crust. -------------------------------------------------------------------------------- Question 3c of 10 ( 2 Characteristics of Earth's Layers 261808 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: Which of Earth's layers is just below the lower mantle? Choice Feedback *A. Outer core B. Crust C. Upper mantle D. Inner core Global Incorrect Feedback The correct answer is: Outer core. The outer core is just below the lower mantle. -------------------------------------------------------------------------------- Question 4a of 10 ( 2 Seismic Waves 165906 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: What is it called when a seismic wave bends as it passes from liquid to solid rock? Choice Feedback A. Absorption That's not it. Absorption is when a wave is absorbed by a surface. B. Reflection That's not it. Reflection is when a wave bounces off a surface. C. Rarefaction That's not it. Rarefaction is the spreading out of a gas. *D. Refraction That's correct! Global Incorrect Feedback The correct answer is: Refraction. -------------------------------------------------------------------------------- Question 4b of 10 ( 2 Seismic Waves 261809 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: What is it called when a seismic wave bounces backward as it reaches a boundary? Choice Feedback A. Absorption B. Refraction C. Rarefaction *D. Reflection Global Incorrect Feedback The correct answer is: Reflection. -------------------------------------------------------------------------------- Question 4c of 10 ( 2 Seismic Waves 261810 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: The bending of a seismic wave as it crosses a boundary is called _____. Choice Feedback A. absorption B. reflection C. rarefaction *D. refraction Global Incorrect Feedback The correct answer is: refraction. -------------------------------------------------------------------------------- Question 5a of 10 ( 3 Seismic Waves 165907 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: The shadow zone exists because ? Choice Feedback A. seismic waves cannot travel through solid rock. That's not it. Both kinds of seismic waves can travel through solid rock. *B. P waves refract as they travel through Earth. That's correct! C. the mantle and core are composed of the same material. That's not it. The mantle and core are made of different materials. This is what causes the refraction that creates the shadow zone. D. sunlight blocks out P waves in certain regions. That's not it. Despite the word "shadow," the shadow zone has nothing to do with sunlight. Global Incorrect Feedback The correct answer is: P waves refract as they travel through Earth. -------------------------------------------------------------------------------- Question 5b of 10 ( 3 Seismic Waves 261811 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: The shadow zone exists due to the _____ of seismic waves. Choice Feedback A. reflection *B. refraction C. absorption D. deletion Global Incorrect Feedback The correct answer is: refraction. -------------------------------------------------------------------------------- Question 5c of 10 ( 3 Seismic Waves 261812 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: The shadow zone exists because: Choice Feedback A. seismic waves cannot travel through liquids. *B. the mantle and core are composed of different material. C. P waves reflect as they travel through Earth. D. sunlight blocks out S waves in certain regions. Global Incorrect Feedback The correct answer is: the mantle and core are composed of different material. -------------------------------------------------------------------------------- Question 6a of 10 ( 2 Characteristics of Earth's Layers 338126 ) Maximum Attempts: 1 Question Type: Matching II Maximum Score: 5 Question: Match the layer with its characteristic. Choice Text Correct Match Match Text A. Crust D. Separates the crust and mantle B. Mantle C. Mostly iron C. Core A. About 40 km thick on average D. Moho Barrier B. Diamonds form here Attempt Incorrect Feedback 1st That's not it. Think of how each layer behaves. Correct Feedback That's correct! Global Incorrect Feedback The correct answers are: Mantle: Diamonds form here Crust: About 40 km thick on average Core: Mostly iron Moho Barrier: Separates the crust and mantle The core is mostly iron; this is how it creates a magnetic field. The mantle is where diamonds form. The Moho Barrier separates the mantle and the crust. The crust is the thinnest layer, about 40 km thick on average. -------------------------------------------------------------------------------- Question 6b of 10 ( 2 Characteristics of Earth's Layers 338127 ) Maximum Attempts: 1 Question Type: Matching II Maximum Score: 5 Question: Match the layer with its characteristic. Choice Text Correct Match Match Text A. Crust D. Separates the crust and mantle B. Mantle C. Creates a magnetic field C. Core A. Thinnest layer D. Moho Barrier B. Composed of peridotite Attempt Incorrect Feedback 1st Correct Feedback That's correct! Global Incorrect Feedback The correct answers are: Mantle: Composed of peridotite Crust: Thinnest layer Core: Creates a magnetic field Moho Barrier: Separates the crust and mantle The core creates a magnetic field. The mantle is composed of peridotite. The Moho Barrier separates the mantle and the crust. The crust is the thinnest layer. -------------------------------------------------------------------------------- Question 6c of 10 ( 2 Characteristics of Earth's Layers 338128 ) Maximum Attempts: 1 Question Type: Matching II Maximum Score: 5 Question: Match the layer with its characteristic. Choice Text Correct Match Match Text A. Crust D. Separates the crust and mantle B. Mantle C. Has a liquid and solid layer C. Core A. Ranges from 6 km to 70 km thick D. Moho Barrier B. Convection here leads to earthquakes Attempt Incorrect Feedback 1st Correct Feedback That's correct! Global Incorrect Feedback The correct answers are: Mantle: Convection here leads to earthquakes Crust: Ranges from 6 km to 70 km thick Core: Has a liquid and solid layer Moho Barrier: Separates the crust and mantle The core has a liquid layer and a solid layer. The mantle has convection cells that lead to earthquakes. The Moho Barrier separates the mantle and the crust. The crust is the thinnest layer, ranging from about 6 km to 70 km in thickness. -------------------------------------------------------------------------------- Question 7a of 10 ( 2 Earth's Crust 165910 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: The continental crust is ? Choice Feedback A. made of rock 200 million years old. That's not it. Continental crust is upwards of 4.4 billion years old. B. composed mostly of basalt. That's not it. Oceanic crust is composed mostly of basalt. *C. up to 70 km thick. That's correct! D. formed from quickly-cooled lava. That's not it. Quickly cooled lava describes basalt, a component of oceanic crust. Global Incorrect Feedback The correct answer is: up to 70 km thick. -------------------------------------------------------------------------------- Question 7b of 10 ( 2 Earth's Crust 261813 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: The continental crust is: Choice Feedback A. made of rock 200 million years old. B. up to 6 km thick. *C. composed mostly of granite. D. formed from quickly-cooled lava. Global Incorrect Feedback The correct answer is: composed mostly of granite. -------------------------------------------------------------------------------- Question 7c of 10 ( 2 Earth's Crust 261814 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: The continental crust is: Choice Feedback A. made of rock 50 million years old. B. composed mostly of basalt. *C. formed from slowly-cooled lava. D. less than 10 km thick. Global Incorrect Feedback The correct answer is: formed from slowly-cooled lava. -------------------------------------------------------------------------------- Question 8a of 10 ( 2 Characteristics of Earth's Layers 165911 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: In which layer is the temperature the highest? Choice Feedback A. The crust That's not it. The crust is the layer on which we live and is the coolest layer. B. The lower mantle That's not it. The mantle is not as hot as the core; the deeper you go, the hotter it gets. C. The outer core That's not it. The outer core is not as hot as the inner core; the deeper you go, the hotter it gets. *D. The inner core That's correct! Global Incorrect Feedback The correct answer is: The inner core. -------------------------------------------------------------------------------- Question 8b of 10 ( 2 Characteristics of Earth's Layers 261815 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: In which layer is the temperature the lowest? Choice Feedback A. The inner core B. The lower mantle C. The outer core *D. The crust Global Incorrect Feedback The correct answer is: The crust. -------------------------------------------------------------------------------- Question 8c of 10 ( 2 Characteristics of Earth's Layers 261816 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: In which layer is the pressure the highest? Choice Feedback A. The crust B. The lower mantle C. The outer core *D. The inner core Global Incorrect Feedback The correct answer is: The inner core. -------------------------------------------------------------------------------- Question 9a of 10 ( 3 Characteristics of Earth's Layers 165912 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: Why do scientists think Earth's core contains iron? Choice Feedback A. The crust also contains a great deal of iron. That's not it. The crust does not contain much iron, which is why scientists think the iron sank into the core. *B. Iron is a heavy element and would sink into the planet. That's correct! C. Iron does not conduct electricity. That's not it. Iron does conduct electricity, which is why it can create a magnetic field. D. Iron is lighter than silicon. That's not it. Iron is heavier than silicon, which means it will sink to the core, while silicon stays up on Earth's crust. Global Incorrect Feedback The correct answer is: Iron is a heavy element and would sink into the planet. -------------------------------------------------------------------------------- Question 9b of 10 ( 3 Characteristics of Earth's Layers 261817 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: Why do scientists think Earth's core contains iron? Choice Feedback *A. The crust does not contain much iron. B. Iron does not conduct electricity. C. Iron is lighter than oxygen. Global Incorrect Feedback The correct answer is: The crust does not contain much iron. -------------------------------------------------------------------------------- Question 9c of 10 ( 3 Characteristics of Earth's Layers 261818 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: Why do scientists think Earth's core contains iron? Choice Feedback A. The crust is made mostly of nickel. *B. Samples of Earth's crust contain less iron than meteorites. C. Iron cannot generate a magnetic field. D. The moon has a similar core. Global Incorrect Feedback The correct answer is: Samples of Earth's crust contain less iron than meteorites. -------------------------------------------------------------------------------- Question 10a of 10 ( 3 Seismic Waves 165913 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: Scientists have been able to determine the composition of Earth's layers by: Choice Feedback A. drilling down and bringing up samples to study. That's not it. They have not been able to drill past the crust. *B. making inferences based on data from seismic waves. That's correct! C. shooting X-rays into the planet. That's not it. X-rays are not used. They use seismic waves, which are produced by earthquakes. D. studying photographs taken from satellites. That's not it. Satellite photographs can only show the surface of the planet. Global Incorrect Feedback The correct answer is: making inferences based on data from seismic waves. Scientists have been able to determine the composition of Earth's layers by making inferences based on data from seismic waves. -------------------------------------------------------------------------------- Question 10b of 10 ( 3 Seismic Waves 261819 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: How have scientists been able to determine the composition of Earth's layers? Choice Feedback A. By studying the magnetic fields of various planets and moons *B. By looking at how seismic waves change speeds as they travel through Earth C. By looking at how X-rays affect the planet D. By studying layers of other planets and moons Global Incorrect Feedback The correct answer is: By looking at how seismic waves change speeds as they travel through Earth. Scientists have been able to determine the composition of Earth's layers by making inferences based on data from seismic waves. -------------------------------------------------------------------------------- Question 10c of 10 ( 3 Seismic Waves 261820 ) Maximum Attempts: 1 Question Type: Multiple Choice Maximum Score: 5 Question: Which is a method that scientists use to determine the composition of Earth's layers? Choice Feedback A. Drilling down and bringing up samples to study *B. Comparing the composition of the crust to other bodies in the solar system C. Shooting seismic waves into the planet and seeing how they travel D. Using remote sensing techniques in the ocean Global Incorrect Feedback The correct answer is: Comparing the composition of the crust to other bodies in the solar system. Scientists have been able to determine information about the composition of Earth's layers by comparing the composition of the crust to the composition of meteorites and comets. --------------------------------------------------------------------------------