Earth Science Text Assignments
Chapter 1: Plate Tectonics
Section 1 (pgs 6-13)
1. Describe what is happening on the south side of the island of Hawaii?
Lava flow out of MountKilauea making the island grow.
2. What happens when lava reaches the sea?
The lava cools and hardens
3. What has happened to the Earth’s surface over its long history?
Earth’s surface has been lifted up, pushed down, bent, and broken.
4. About how deep is the deepest mine on Earth?
3.8 Kilometers
5. How deep is the Earth’s center?
Over 6,000 kilometers
6. What two types of evidence do geologists use to learn about the Earth's interior?
Direct and indirect evidence are used to learn about earth’s interior
7. How do scientists obtain the rock samples from the Earth’s interior?
Scientist obtain rock samples through drilling and when rock is blasted to the earth’s surface.
8. What do earthquakes produce to help scientists learn about Earth’s interior?
Earthquakes produce seismic waves.
9. What do scientists record and study to learn about the interior from these events?
Scientists study these seismic waves and the speed of them reveals the structure of the planet.
10. What characteristics of these events, specifically, do they rely on?
Scientists rely on the speed of the waves.
11. What are the three main layers of the Earth?
The three main layers are the crust, the mantle and the core.
12. What is different about these layers of the earth?
The layers vary in size, composition, temperature, and pressure.
13. Describe what happens to temperature as you descend into the Earth
Temperature increases after the first 20 meters.
14. Describe why pressure increases with depth.
Pressure increases with depth because the force of the rock above pushes on the rock below.
15. What are the two types of crust and what is it composed of and where are each located?
Oceanic crust which is under the ocean is made of basalt and continental crust is made of granite.
16. What characteristics are used to divide the layers of the mantle?
Physical characteristics
17. Name and compare the three layers of the mantle.
Lithosphere-upper most part of the mantle and the crust
Asthenosphere-soft rock
Lower mantle-solid material
18. What is the core of the Earth made of? What are the two parts called?
The core is made of iron and nickel. The two parts are the inner core and the outer core.
19. Overall, what is the total depth in Km, including the core, to the center of the Earth? How many miles is that? (1 mi = 0.62 Km)
3, 486 km =5622.58 miles
20. How are the Earth’s magnetic fields created?
The movement of the liquid in the outer core creates a magnetic field.
Section 2 (pgs 14- 17)
21. What are the three types of heat transfer?
Radiation, conduction, convection are the three types of heat transfer.
22. What is radiation and give an example?
The transfer of energy through empty space. Ex: sunlight, fire
23. What is conduction and give an example?
Heat transfer by direct contact of particle of matter. Ex: heat transfer to a spoon
24. What is convection and give an example?
Heat transfer by the movement of a heated fluid. Ex: heating soup
25. What is density defined as?
How much mass there is in a volume of a substance
26. What are convection currents?
Flow that transfers heat within a fluid
27. What three factors set convection currents in motion?
The three factors include heating and cooling of the fluid, changes in the fluid’s density, and the force of gravity.
28. Make a diagram showing convection currents in the aesthenosphere
Section 3 (18-22)
29. What was Wegener’s hypothesis about the continents?
All continents had once been joined together in a single landmass and have since drifted apart.
30. What did he name his supercontinent?
Pangaea
31. List 3 evidences that support Wegener’s idea of continental drift.
Evidence comes from landforms, fossils, and climateto support Wegener’s idea.
32. Why was Wegener’s theory ultimately rejected by his peers?
He could not provide a satisfactory explanation for the force that pushes or pulls the continents.
Section 4( pgs 23-29)
33. What are some of the strange creatures that live near “vents” in the ocean?
Giant red-tipped tube worms, giant clams, spiderlike crabs are some of the strange creatures.
34. What is the mid ocean ridge?
Longest chain of mountains in the world, extends into all of the earth’s oceans
35. What is sonar and what does it show about features beneath the ocean?
Sonar is a device that bounces sound waves off underwater objects and records echoes of these sound waves. It allows the sea floor to be mapped.
36. Describe Harry Hess’s idea of “sea floor spreading”.
At the mid-ocean ridge, molten material rises from the mantle and spreads out pushing older rock to both sides of the ridge.
37. What types of evidence supported Hess’s ideas?
Evidence from molten material, magnetic strips, and drilling samples support Hess’s ideas.
38. Explain how the three types of evidence from molten material supported the theory of sea floor spreading.
*Rocks shaped like pillows or like toothpaste squeezed from a tube. These rocks can only be formed when molten material hardens quickly after erupting.
*The rocks in the ocean floor contain iron and when they cool the line up in the direction of the earth’s magnetic poles. Rock that hardens at the same time has the same magnetic memory. Strips of rock are parallels, alternating north and south magnetic fields
*drilling samples showed rocks farther away for the ridge were older.
39. Two islands are measured to be 100 and 700 kilometers from the mid ocean ridge. Which island is younger and why?
The 100 km island because rocks are increase in age the farther they are from the ridge.
40. What process occurs at deep ocean trenches?
Subduction
41. How do subduction zones help recycle the Earth’s crust?
Subduction allows parts of the ocean floor to sink back into the mantle
42. How long does subduction take?
Subduction takes tens of millions of years
43. Explain why the Pacific Ocean is shrinking.
The Pacific Ocean has many trenches and sometimes trenches can swallow more rock faster than new crust can be produced.
44. Explain why the Atlantic Ocean is expanding.
The Atlantic has a few short trenches and since it is attached to the North America it pushes it back.
Section 5 (pgs 32 – 36)
45. What did J. Tuzo Wilson propose about how the lithosphere is organized?
Wilson proposed that the lithosphere is broken into separate sections called plates.
46. What is a “scientific theory”?
A scientific theory is a well tested concept that explains a wide range of observations.
47. What does the theory of “plate tectonics” explain?
The theory of plate tectonic explains the formation, movement and subduction of Earth’s plates.
48. How can plates be moved?
Geologists believe that plates can be moved due the convection currents within the mantle.
49. What is produced when plates collide, pull apart or grind past one another? List specific examples.
When plates collide, pull apart and grind past each other, spectacular changes in Earth’s surface result such as volcanoes, mountain ranges, deep ocean trenches.
50. What is a fault?
A fault is breaks in the Earth’s crust along plate boundaries where rocks slip past each other.
51. What are the three types of plate boundaries?
The three types of plate boundaries are: Divergent, convergent and transform.
52. How do scientists detect movement of the pates and at what rate are they moving?
Scientists use instruments on satellites to measure plate motion precisely. Plates move at a rate of about 1 to 24 cm per year.
53. Define a divergent boundary, what forms as a result of this type of boundary?
A divergent boundary is a place where two plates move apart. Mid oceans ridges and rift valleys on land are formed.
54. Define a convergent boundary, what happens at this type of boundary?
A convergent boundary is a place where two plates come together or collide.
55. Explain what happens when continental and oceanic crust collide?
When continental and oceanic crust collides, density plays an important role in which plate comes out on top. Oceanic crust is denser, therefore is slips below the continental crust creating a zone of subduction.
56. Describe what happens when two continental plates collide?
When two continental plates collide, neither plate is denser that the other, therefore a mountain range is formed.
57. Define a transform boundary, what is typically produces as a result of this type of boundary?
A transform boundary is a place where two plates slip past each other moving in opposite directions. Earthquakes are produced as a result of this movement.