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EXPLORING EARTH’S
SURFACE
Lesson 4
Introduction
Lewis and Clark
In 1804, an expedition set out from near Saint Louis to explore the land
between the Mississippi River and the Pacific Ocean, The United States
had just purchased part of this vast territory from France. Few had
traveled far to the west.
Led by Meriwether Lewis and William Clark, the expedition first traveled up
the Missouri River. Then the group crossed the Rocky Mountains and
followed the Columbia River to the Pacific Ocean.
Big
Question
If you were going
on an expedition
to explore
unknown territory,
what supplies
would you bring
with you and
why? Choose
only five items.
Vocabulary Words
◦ Topography-is the shape of the land; it includes the area’s elevation, relief,
and landforms
◦ Elevation-the height above sea level of a point on Earth’s surface
◦ Relief-the difference in elevation between the highest and lowest parts of
an area
◦ Landform-is a feature of topography, such as a hill or valley, formed by the
processes that shape Earth’s surface; different landforms have different
combinations of elevation and relief
◦ Plain-is a landform made up of nearly flat or gently rolling land with low
relief
◦ Mountain-is a landform with high elevation and high relief
◦ Mountain base-is the base of a mountain, it can cover an area
of several square kilometers or more
◦ Mountain range-is a group of mountains that are closely
related in shape, structure, area, and age
◦ Plateau-a landform that has high elevation and a more or less
level surface; it is rarely perfectly smooth on top; rivers and
streams may cut into the plateau’s surface
◦ Landform region-a large area of land where the topography is
made up mainly of one type of landform
What Does the Topography of an Area Include?
Elevation
Relief
◦ The height above the sea level of
a point in the Earth’s surface
◦ The difference in elevation between the
highest and lowest parts of an area
◦ When Lewis and Clark started their
journey, they were about 140
meters above the sea level
◦ Early in their journey, they encountered
flat or rolling land that had low relief, or
small differences in elevation
◦ By the time they reached Lemhi
Pass in the Rocky Mountains, they
were more than 2,200 meters
above sea level
◦ In the Rocky Mountains, they crossed
huge mountains separated by deep
valleys
◦ These areas had high relief, or great
differences in elevation
Landforms
◦ If you followed the route of their
expedition, you would see many
differences in landforms.
◦ A landform is a feature of
topography, such as a hill or
valley, formed by the process
that shapes Earth’s surface
◦ Different landforms have
different combinations of
elevation and relief
CRITICAL THINKING
The word topography is a combination of two Greek
words: topos that means “place” and graphia that
means “to write”.
How does the word’s origin relate to its scientific
meaning?
What Are the Main Types of Landforms?
◦ Landforms vary greatly in size and shape
◦ They include level plains extending as far as the eye can see, rounded
hills that you could climb on foot, and jagged mountains difficult to hike
through
◦ Three major types of landforms are: plains, mountains, and plateaus
Types of Landforms
Plains
◦ Made up of nearly flat or gently rolling land with low relief
◦ A plain that lies along the seacoast is known as a coastal plain
◦ In North America, a coastal plain extends around the continent’s
eastern and southeastern shores
◦ Coastal plains have both low elevation and low relief
◦ A plain that lies away from the coast is called interior plain
◦ Interior plains are often low and have low relief, but their elevations
can vary
◦ The broad interior plains of North America are called the Great
Plains
Mountains
◦ A mountain is a landform with high elevation and high relief
◦ A mountain’s base can cover an area of several square kilometers or more
◦ Mountains usually exist as part of a mountain range
◦ A mountain range is a group of mountains that are closely related in shape,
structure, area, and age
◦ The different mountain ranges in a region make up a mountain system
◦ The Bitterroot Mountains are one mountain range in the mountain system known
as the Rocky Mountains
◦ Mountain ranges and mountain systems in a long, connected chain form a larger
unit called a mountain belt
◦ The Rocky Mountains are part of a great mountain belt that stretches down the
western sides of North America
Rocky
Mountains
The Rocky Mountains
stretch more than
3,000 miles (4,830 km)
from the
northernmost part of
British Columbia, in
western Canada, to
New Mexico, in the
southwestern United
States. The range's
highest peak is Mount
Elbert located
in Colorado at 14,440
feet (4,401 m) above
sea level.
LEARN MORE ABOUT THE ROCKY MOUNTAINS
https://www.princeton.edu/~achaney/tmve/wiki100k/docs/Rocky_Mountains.html
Plateau
◦ A plateau is a landform that has high elevation and a more or less level
surface (low relief)
◦ It is rarely perfectly smooth on top
◦ Streams and rivers may cut into its surface
◦ The Columbia Plateau in Washington State is an example
◦ The Columbia River, which Lewis and Clark expedition followed , slices
through this plateau
◦ The many layers of rock that make up the Columbia Plateau rise as high
as 1,500 meters
Palouse
River
Canyon
Basalt
fractures in
the plateau
Landform Regions
◦ A landform region is a large area of land where the topography is
made up mainly of one type of landform
◦ The Great Plains and the Rocky Mountains are examples of major
landform regions in the U.S.A.
◦ All of the land in one major landform region tends to have much in
common. For example, the land of the Atlantic Coastal Plain is
generally of low elevation and relief
◦ There are different landform regions: coastal plains, interior plains or
lowlands, mountains, plateaus or uplands, basins
Videos about Landforms
◦ http://www.youtube.com/watch?v=KWTDmg8OI_Y
◦ http://www.youtube.com/watch?v=0f3sX9lK4pU
Assess
◦ Place these features in order from smallest to largest:
mountain system, mountain range, mountain belt, and
mountain
◦ Answer-mountain, mountain range, mountain system,
mountain belt
Questions
◦ 1.) The topography of an area includes: ________, _______, and _________
◦ 2.) How do the elevations of hills, valleys, and mountains compare?
◦ 3.) Which two landforms are relatively flat features with low relief?
◦ 4.) How is a plain different from a plateau?
◦ 5.) Which landform has high elevation and high relief?
◦ 6.) Which landform region would have long ocean beaches?
◦ 7.) In which landform region could you visit many ski resorts?