Download File - Science 8 core

Answers to WS 8.1
Geological Features at Sea and on Land p. 218
1. What has water done to Niagara Falls over the past 12000 years? Moved the edge of the falls
upstream 11 km
2. What will you study in this chapter? How water plays a role in shaping earth and determining the
climate in different regions
3. Describe the present day theory of plate tectonics based up on the work of Alfred Wegener.
Earths crust is made of sections called tectonic plates that float and move slowly around the earth
4. Describe Pangaea. A place 225 million years ago made of all the plates stuck together fg 1 p. 219
5. Define continental shelf. Place where the ocean floor slopes gently downward, away from the
continents
fg 3 p. 220
6. Why is the continental shelf important? Abounds in sea life
7. What is the continental shelf part of? Part of the continental crust and is an extension of the
continent, even though it is under the ocean
fg 2 p. 220
8. Define continental slope. Steeply sloped region that forms after the continental shelf
220
fg3 p.
9. What does the dark line show in figure 2? Continental slope
10. Explain the difference between a continental shelf and a continental rise. Continental rise is a
gentle slope that goes from bottom of the ocean to the continental slope. The continental slope is
a steep slope that connects the continental rise to the continental shelf
continental rise is the
place were the oceanic plate meets the continental plate
11. Define abyssal plains. Large flat ocean bottom
12. Why is the abyssal plains flat? Sediment from rivers and streams over time fill up holes and
basins
13. List two interesting things about the Mid-Ocean Ridge. Longest mountain range, goes through all
4 oceans of the world
14. Define volcano. Mountain that is formed when hot lava erupts through the Earth’s crust and
solidifies repeatedly
fg 4 p. 220
15. Define seamount. Underwater volcano fg 4 p. 220
16. How were the 19 Hawaiian Islands formed? Volcanic islands
17. Define guyot. A volcanic island that over time was eroded so that it is completely covered by
ocean again
fg 4 p. 220
18. FG. 4. What is the difference between a seamount and a guyot? Guyot is a volcanic island that
has been worn away
19. Define canyon. Deep, steep-sided valleys
20. How do most canyons form? formed by rivers that cut away the rock that it flows down
21. Define trench.
fg 5 p. 221
places where 2 oceanic tectonic plate collides with another tectonic plate
22. What is occurring in figure 5?
process is producing a trench
One plate is being pushed underneath another plate and in the
23. How wide might an ocean trench be? 200 km
24. Define basin. Depressions in the Earth’s surface
25. Describe how glaciers formed many lakes. Glaciers carved out large depressions on the Earth
during the last ice age
26. What is the difference between an inlet and an outlet? Inlet: place where river enters a lake,
outlet: place where river leaves a lake
27. How can landlocked lakes be saltier then ocean water? Ground water dissolves salts and minerals
form the soil and rock, and then carries these materials into the landlocked lake
28. Fg. 6a. What is a dam? A place where a river is blocked and water builds up forming a lake
29. Fg. 6b. List several ways natural dams may be caused. Landslides, lava flows, river deposits, ice,
or beavers
30. List 3 origins of rivers. Mountains, springs, glacier meltwater
31. What is a spring? Water coming (welling) up from under ground
32. What do tributaries do to a river? Join the river, adding water to it
33. When is river sediment deposited? When the water’s movement slows
34. Fg. 7. What are some differences between a young, fast-flowing river and an older one? Young
and fast have steep banks and few bends,
old rivers: a large flood plain around it, many
bends (meanders), gentle slopes
35. Define watershed. An area surrounded by high-elevation land in which all water runs to a
common destination
fg 8 p. 223
36. Fg. 8. Why does water go in two different directions on a mountain? The rain on 1 side of the
mountain flows 1 way, the other side flows the other way (front side, back side)
37. What does each watershed contain? Many smaller water sheds
38. Define Continental Divide. (Mountains that divide the continent) See fg 9 p. 224 tips of the
Rocky Mountains: it separates water flowing to the west into the Pacific Ocean from water that
will flow north into the Artic Ocean and East into the Atlantic ocean
39. Where is the Columbia Icefield. See fg 9 pl 224 at the heart of the continental Divide
40. Explain FG. 9. mountains split North America into 4 different drainage basins: the rain will then
flow into 1 of 4 directions, depending on which side of the mountain range it fell on