Water Shapes the Land

Size: px

Start display at page:

Download "Water Shapes the Land"

Marshall Charles
7 years ago
Views:

1 Indicate the answer choice that best completes the statement or answers the question. Water Shapes the Land Did you know that about three-fourths of Earth's surface is water? And that water is always moving? Streams begin as tiny trickles of water, high in the mountains. As streams flow downhill, they merge into rivers. River waters rush on, often emptying into oceans. In the oceans, water circulates continuously, moving around the globe. Waves never stop churning against shorelines and cliffs. Even frozen ice is on the move, creeping along Earth's surface. The natural forces of water and ice on Earth have slowly carved Earth's surface over centuries. Every day, water and ice flow. They move soil and wear away rock. This changes the shape of the land slowly, like a painting that is never finished. Carving Canyons Imagine standing at the edge of the Grand Canyon. At your feet is a narrow, rocky valley stretching as far as you can see. The walls of the canyon form colored bands sloping steeply one mile deep. At the bottom, you can see the Colorado River winding like a snake through the canyon. How did this enormous canyon come to be? The Colorado River played a critical role in the formation of the Grand Canyon. Canyons form as water flows and picks up rocks. The rocks dash against the sides of the canyon, acting like chisels. Over time, the rocks wear away. It took centuries, but the Colorado River shaped this natural wonder. Waves and Rivers Like rivers, ocean waves can carve and shape the land. The power of waves striking shorelines and cliffs wears them away. In some places, they produce striking rock formations. A sea cave, for example, is formed when waves wear away the base of a cliff, leaving a cavity in the rock. In other places, one section of shoreline might wear away more quickly than another because of waves. This can result in the formation of an inlet or a harbor. Oceans and rivers carry material from one place to another. Waves deposit sand along the shore, creating long, sandy land forms called barrier islands. Large rivers move small rocks and other materials, called sediment. Over time the sediment forms low-lying areas called river deltas. The Mississippi River delta is the best-known deltain the United States. This delta is a spider web of land and water sprawling from the mouth of the river into the Gulf of Mexico. Powered by Cognero Page 1

2 Ice on the Move In extremely cold places, such as the north and south poles, huge bodies of ice and tightly-packed snow form. These bodies, called glaciers, are so heavy that their own weight causes them to move. As they slowly move, glaciers carve and shape Earth's surface in much the same way as rivers and oceans. The huge ice sheets are bulldozers, pushing rocks and other loose materials as they creep along. Glaciers pick up large boulders, called erratics, and carry them over long distances. Long, long ago, enormous glaciers covered large parts of Earth's surface. Much of what is now the upper Midwestern United States was covered in ice. This huge glacier flattened the region as it crept along. It carved out big chunks of land. Then temperatures rose and the glacier began to retreat, or melt. Basins were left behind. The melting ice filled them with water, forming the Great Lakes. Alpine glaciers are found on mountain tops where it is cold enough to keep snow from melting. Alpine glaciers move slowly, forming U-shaped valleys and bowl-like depressions. 1. Which sentence best expresses the main idea of the article? a. Rivers play a role in forming canyons and deltas. b. Glaciers are bodies of ice so heavy that they move. c. Water makes up about three-fourths of Earth's surface. d. Water and ice have shaped Earth's surface over many centuries. 2. Read this sentence from the article. In the oceans, water circulates continuously, moving around the globe. What does circulates mean in the sentence above? a. combines b. drains c. freezes d. travels Powered by Cognero Page 2

3 3. Read this sentence from the article. And so the shape of the land slowly changes, like a painting that is never finished. Why does the author compare the land to a painting that is never finished? a. to show that the land is slowly disappearing b. to show that the land is beautiful and colorful c. to show that the shape of the land is still changing d. to show that the shape of the land is affected by water 4. Read this sentence from the article. At the bottom, you can see the Colorado River winding like a snake through the canyon. What does the simile in the sentence above mean? a. The river twists and turns on its path through the canyon. b. The river sparkles a green color at the bottom of the canyon. c. The river runs in and out of holes along the base of the canyon. d. The river makes a hissing sound as it flows through the canyon. 5. Which detail would best support the main idea of the section "Carving Canyons"? a. The Colorado River runs through seven states. b. Every year, many people visit the Grand Canyon. c. The Colorado River supports plant and animal life. d. Many centuries ago, the Grand Canyon did not exist. Powered by Cognero Page 3

4 6. Read this sentence from the article. This delta is a spider web of land and water sprawling from the mouth of the river into the Gulf of Mexico. Why does the author compare the Mississippi River delta to a spider web? a. to show that the land in the delta slows the river's flow b. to show that the mouth of the river covers a large area c. to show that the land and water form complex patterns d. to show that the delta traps many fish and small animals 7. Which feature on Earth's surface was formed by a glacier? a. sea caves b. barrier islands c. the Great Lakes d. the Grand Canyon 8. What text evidence supports the main idea of the section "Ice on the Move"? a. Glaciers have slowly shaped Earth's surface. b. Water continues to move even when it is frozen. c. Glaciers are found in Antarctica and on mountain tops. d. Large parts of Earth's surface were once covered by glaciers. 9. Read this sentence from the article. The huge ice sheets are bulldozers, pushing rocks and other loose materials as they creep along. What does the metaphor in the sentence above mean? a. Glaciers move very slowly. b. Glaciers are a powerful force. c. Glaciers move over large areas. d. Glaciers are a type of machine. Powered by Cognero Page 4

5 10. Which paragraph would the following detail best support? Glaciers carve out jagged ridges in the mountains, as well as peaks, called horns, where the ridges meet. a. paragraph 7 b. paragraph 8 c. paragraph 9 d. paragraph 10 Powered by Cognero Page 5

Earth Science Landforms, Weathering, and Erosion Reading Comprehension. Landforms, Weathering, and Erosion

Earth Science Landforms, Weathering, and Erosion Reading Comprehension. Landforms, Weathering, and Erosion Reading Comprehension Name 1 How many people have been to the Rocky Mountains or the Grand Canyon? When people go to visit these natural wonders, they may not realize that it took millions of years for