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Lesson 12
Genre: Expository Nonfiction
Genre: Magazine Article
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Focus Skill
Text Structure: Cause and Effect
Authors of nonfiction texts may organize information in a cause-and-effect text structure. In
texts with this structure, the author tells what happened (the effect) and why it happened
(the cause). Sometimes a cause has more than one effect. You can use a graphic organizer
like this one to keep track of the cause-and-effect relationships in the text.
Cause
Effect
Effect
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Read the paragraph below. The graphic organizer shows the cause-and-effect relationship in the
last two sentences. The phrase as a result signals the effects.
Cause
The climate warmed.
Effect
The ice melted away.
Effect
The land had deep valleys and lakes.
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Vocabulary
Build Robust Vocabulary
eruption
constant
immediate
gradually
depths
revealed
contract
The Double Volcano
Mexico’s largest volcano, Popocatepetl (poh•puh•KA•tuh•peh•tuhl), is often called Popo. Its
last big eruption occurred in 1947. In 1995, another eruption seemed likely. Smoke and
ash started escaping from Popo. After two years, the smoke and ash stopped. Scientists
now keep a constant watch on the volcano. They say that the people who live near Popo
are not in immediate danger.
Popo is a volcano that formed on top of an older volcano.
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Popo has an almost perfect cone shape. Its sides rise gradually for more than 16,000 feet. The
crater at the top is shaped like an oval, and it is very deep. Peering into it is like looking
into the depths of the earth. On one side of Popo, a smaller cone shape sticks out. There,
the remains of an older volcano are revealed.
Popo’s peak is covered with snow. In the icy air, rocks contract and break apart. On its lower
slopes, forests grow. On a clear day, Popo is a beautiful sight.
No one knows when Popo will erupt again.
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Mountines
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Mountains are a dramatic reminder of ages past and ages to come. They seem to be solid and
unchanging, but they are not everlasting. Mountains are born, grow tall over the years,
change their shapes, and are finally worn down and disappear into the earth from which
they came.
The Height of Mountains
Mountains are tall, but just how tall does one have to be to be called a mountain? The
Himalayan Mountains in central Asia have at least fourteen peaks over 26,000 feet. Mount
Everest in the Himalayas is the highest mountain above sea level in the world, 29,028 feet.
That’s five and a half miles above sea level, taller than the world’s twenty-six tallest
skyscrapers stacked one atop another.
Mount Everest
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The Jungfrau
The Alps of Europe, the Andes of South America, and the Rockies of western North America
each have dozens of peaks taller than 10,000 feet. Air temperature drops about three
degrees Fahrenheit for every one thousand feet of altitude, so the peaks of many tall
mountains, such as the Jungfrau in the Alps, are always cold and are covered by snow year
round.
The Appalachians are a group of old, worn mountains 200 miles long in the eastern United
States. Only a few Appalachian peaks are as high as 6,000 feet and many are much lower.
This hill in New York’s Catskill Mountains is less than 3,000 feet above sea level. In the
Himalayas or the Alps, mountains like this would be called foothills. Whether to call
something a mountain seems to depend upon who is looking at it and how high its
surroundings are.
Catskill Mountains
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How Mountains Form
Most mountains are not solitary peaks but part of long chains or ranges. The Himalayas are
over 1,500 miles long and link up with other mountain ranges to stretch hundreds of miles
farther.
Mountain ranges do not arise just anyplace. Most are formed when plates, giant pieces of the
earth’s crust, push and pull against each other. The United States, Canada, Mexico, and
part of the North Atlantic Ocean are on the North American plate. The Rockies and the
coast ranges of the western United States and Canada were formed where the North
American plate pushed against the Pacific plate.
The Mid-Atlantic ridge, a 12,000-mile-long underwater mountain chain that stretches the
length of the Atlantic Ocean, was formed where the North Atlantic plate pulled away from
the Eurasian plate and the African plate. The islands of Iceland and Surtsey are actually the
tops of volcanic mountain peaks reaching above the surface of the ocean, which covers
most of the Mid-Atlantic ridge.
North American Plate
Juan De Fuca Plate
Pacific Plate
Cocos Plate
Nazga Plate
Antarctic Plate
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Caribbean Plate
Mid-Atlantic Ridge
Eurasian Plate
South American Plate
African Plate
Mid-Atlantic Ridge
The Mid-Atlantic ridge runs through the center of Iceland, which is made up entirely of lava.
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Folded peaks in the Rocky Mountains in Montana
Strata
Crust
Rocks are hard, but with time and pressure they can bend or fold. Hold a large piece of paper at
either end and slowly push toward the middle. The pressure of your hands causes the paper
to buckle and fold. In the earth’s crust, pressure pushes sideways against the rocks. The
rocks twist and bend, producing great folded mountain chains. It takes many thousands of
years to bring about changes in the rocks of the earth’s crust.
The Alps are folded mountains that formed as the Eurasian plate pushed against the African
plate. Most of the great mountain chains on earth, including the Himalayas, the Andes, the
Rockies, and the Appalachians, are folded mountains. When the bare mountainside is
exposed, you can see the folds in the layers of rock, called strata, such as these folded
peaks in the Rocky Mountains in Montana.
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Another type of mountain is formed by the pulling apart or breaking of rocks. Faults are breaks
in rock layers, and fault-block mountains form when one plate shifts or pulls away from
another plate. Deep within the earth, hot currents of magma, molten rock, may well up and
crack the weakened crust above. As the crust cracks, huge blocks of rock rise or fall,
forming mountains. These mountains usually have a steep face on one side and a more
gentle slope on the other side. The Sierra Nevada and the Grand Tetons of Wyoming
(shown here) are examples of fault-block mountains.
Crust
Strata
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Still other mountains are formed by the eruption of volcanoes. During a volcanic eruption,
magma squeezes up through cracks in the earth’s crust and explodes out as lava and ash.
When huge amounts of hardening lava and cinders pile up around the vent, or opening,
they form a volcanic mountain, such as Mount Hood in Oregon (above).
The Hawaiian Islands are the tops of volcanic mountains that rise 30,000 feet from the depths
of the ocean, making them even taller than Everest if you measure from the ocean bottom.
The aerial view of Hawaii below shows some of its volcanic cinder cones.
Vents
Magma
Crust
Strata
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Half Dome in Yosemite National Park, California
Strata
Crust
Magma
Dome mountains are formed by the same kind of molten rock that forms volcanic mountains.
Dome mountains do not act or even look like volcanoes. They too result from a welling up
of magma from deep within the earth through a crack in the earth’s crust. However, in
dome mountains, the magma does not come to the surface. Instead, the molten rock pushes
the ground up into a round or dome-shaped bulge, and the magma gradually hardens into
rock. When the softer rocks above are worn away, the great dome of underlying rock is
revealed.
The Adirondacks of New York and the Black Hills of South Dakota are dome mountains.
Yosemite’s Half Dome (above) is a dome mountain that was cracked in half when sheets
of granite fell off one side and were carried away by a glacier thousands of years ago.
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Weathering and Erosion
As soon as mountains rise, they begin to be worn down steadily and slowly by the forces of
erosion: wind, rain, moving water, and ice, as well as temperature and chemical changes.
Some kinds of rocks, such as limestone, dissolve in water, but most water erosion on
mountains is caused by streams and rivers that plunge down the steep sides, lifting up
rocks and pushing them along to rub and scrape against other rocks. In cold climates,
slowly moving rivers of ice, called glaciers, also carve away at mountains.
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Rocks expand daily in the heat of the sun and then contract again during the cold nights. These
constant temperature changes begin to crack the rock. Water gets into the tiny cracks,
freezes at night, expands, and opens the cracks wider. Finally, the rock breaks off from the
mountain. Sometimes the wind blows sand, which wears away mountains to produce
towers such as in Zion National Park in Utah (above).
On steep mountain slopes, rocks tumble downhill, pulled by gravity. Sometimes a rain shower
or a small earthquake can send rocks roaring down the mountainside in a rock slide or rock
avalanche. Rock glaciers, like those shown on the slopes of Shivling Mountain in India
(left), are rivers of small pieces of rock and soil frozen together that move slowly downhill
like ice glaciers.
At the foot of a mountain, piles of broken boulders, smaller rocks, and soil often spread out in a
fan-shaped pile called a talus slope. The material that makes up talus is called sliderock,
and it continues to move downhill.
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Climate Chenges
Mountains change shape slowly, but they have an immediate effect on weather and climate,
especially on the amount of rainfall, the pattern of winds, and the movement of weather
fronts. The reason for this is that mountains break up the flow of winds and force the air to
move up or around. Air contains a certain amount of an invisible gas called water vapor.
The cooler the air, the less water vapor it can hold. When air is forced to rise over a
mountain, it gets colder and the water vapor condenses into tiny drops of water in clouds,
mist, fog, and rain.
In the western United States, moisture-laden winds blow from the Pacific Ocean against the
coastal mountain ranges of Washington, Oregon, and California. Clouds form and rain falls
heavily on the rain forests of the western slopes.
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On the eastern slopes of the mountains in these states, and in Wyoming, Montana, and Nevada,
scarcely any rain falls at all. This is called the rain shadow effect. The driest deserts in
America are separated from the wettest rain forests by only a few hundred miles.
Not many people live on mountains, but mountains are important to all of us. Mountains create
rain forests and deserts. Mountains store water on their snow y peaks and release it in
rivers that make the valleys below green and fertile. Many farms and cities depend on
mountain lakes for their drinking water, and the rivers are often harnessed to manufacture
electricity. Mountains offer a chance for people to climb or ski or just take pleasure from
some of the most spectacular scenery in the world.
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Think Critically
1 What causes rock to expand during the day? TEXT STRUCTURE: CAUSE AND EFFECT
2 Are the earth’s oldest mountains also its tallest mountains? How do you know? DRAW
CONCLUSIONS
3 Where have you seen the effects of water or wind?MAKE CONNECTIONS
4 What might you find if you measured Mount Everest today and then measured it again a
hundred years from now? MAIN IDEA
5 WRITE Different types of mountains form in different ways. Use information and details
from the selection to explain:
• how dome mountains form, and
• how dome mountains are different from volcanic mountains. EXTENDED RESPONSE
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About the Author
Seymour Simon
Seymour Simon taught science for twenty-three years. Often he couldn’t find the right book on
a topic he wanted to teach. So he began to write his own books.
“If you take a walk and really look, listen, and feel the world around you, it can be a strange
experience,” says Seymour Simon. “You begin to wonder about things that you’ve seen
thousands of times—clouds, trees, rocks, machines. You ask questions: Why do some
leaves turn red in the fall, while others turn yellow? What kind of rock has glittery little
specks in it? How is an airplane able to fly? My books are full of questions.” Seymour
Simon’s books have asked—and answered—thousands of questions.
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To the Top of the World
Science
Magazine Article
What would you do to stand at the top of the World? Brave temperatures as low as 40 below?
Cross an ice gorge supported only by two aluminum ladders lashed together? Climb so
high that your oxygen-deprived mind starts playing tricks on you?
All mountains are dangerous and feature unpredictable weather, but Mount Everest is the
granddaddy of them all when it comes to risk. The wind whipping across the mountainside
reaches 80 miles an hour— hurricane force.
With a single missed step, a climber can plunge into an icy crevasse. And even when they reach
the top, climbers are usually too numb with exhaustion and oxygen deprivation to admire
the of glory of the view.
At Everest’s altitude there is so little oxygen that the brain struggles to think. On Everest, even
the smartest person has difficulty figuring out simple things, like which way to turn the
valve on an oxygen tank to shut it off, or in which direction to walk.
Why do it, then? For filmmaker David Breashears, climbing is a passion, and climbing Everest
is the ultimate. Breashears was asked about how he scaled Mount Everest in pursuit of
amazing film footage. Here is what he said about the experience.
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I left for work in the pitch of darkness. It was 38 degrees below zero. I walked out into a place
where the air is so thin that a person could suffocate, where no animal or plant could
survive. I was carrying a 40-pound movie camera nearly five and a half miles into the sky,
to the top of the world.
My crew and I were on Mount Everest filming a movie in a special format called IMAX.
IMAX creates movies that are viewed on huge screens and give viewers a feeling of really
being there. This was my chance to show people what it’s like to stand on top of the world.
I’m David Breashears, one of the world’s few mountain-climbing filmmakers. I’ve seen it all at
high altitude: joy, pain, excitement—and, sadly, death.
The Path to the Top
I was born in Fort Benning, Georgia. I grew up all over the world as my dad, an army major,
was stationed in different places. Now I live in Newton, Massachusetts, when I’m not on
location, making movies.
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David Breashears uses his breath to keep his viewfinder free of ice.
Next, I want to make a movie about Kilimanjaro, Africa’s tallest peak. I’m also writing a book
on my experiences.
My love of mountain-climbing came before I decided to become a filmmaker. When I was 12, I
saw a picture of Tenzing Norgay standing on top of Mount Everest. Sir Edmund Hillary,
the New Zealand mountaineer and Norgay’s climbing partner, had taken the picture. They
were the first to climb Everest, back in 1953. The other climbers in their party had given
up. Norgay and Hillary went on to the summit alone. That image of Norgay stuck with me
and sparked my interest in climbing.
I started climbing in high school as an alternative to team sports, which I wasn’t very good at. I
was too skinny. But climbing built up my muscles, and it taught me many other things too.
Many things I learned as a Boy Scout in Troop 225, Cheyenne, Wyoming, have been vital in
my climbing. Winter camping is one of the best things you can do. It teaches you what you
need to survive.
I know about surviving: I’ve climbed Everest eleven times and led the trip four times. In 1983,
I was the first to send TV pictures from the summit, and I was the first American to reach
the summit twice.
Funny thing is, I don’t like heights. But making movies at high altitudes is what I do. My
climbing skills make it possible for me to make some amazing movies, like the IMAX film
“Everest.”
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Survival Mode
You might think that once you get to the top of Everest, you give your climbing partners highfives. Not true. When you’re on Everest, you’re in survival mode. Emotions take up a lot
of energy, so you can’t have strong emotions.
After all, reaching the summit isn’t the end—it’s only halfway. And walking downhill is
dangerous; gravity’s with you, and it’s easy to fall. You have to remember that the finish
line on any hike is back where you started.
An Extra Load
Climbing is a challenge in itself, and climbing with the IMAX camera is even more so.
The standard IMAX camera is big— it weighs 92 pounds—so we developed a lighter version
to take up the mountain. The rolls of film are 500 feet long, weigh five and a half pounds,
and shoot just 90 seconds of images.
Setting the camera up, filming, and taking it down took an hour altogether. I had to take off my
gloves to load the film, but I had practiced by sticking my hands into a mountaintop
snowbank for a minute to make sure I could do it.
The Importance of Learning
I didn’t go to film school, unlike a lot of other filmmakers. Instead, I carried cameras, ran
sound, and did the other behind-the-scenes tasks that go into making a movie. An
apprenticeship— studying with people older and wiser than you—is a great way to learn.
If you want to succeed, I’d give you this advice: Have a passion, something you really want to
do, like climbing mountains, making music, or building things. Then, learn everything you
can about what you want to do. That way, you never forget—whether you’re making a
movie or trying to climb the world’s tallest mountain. Remembering can save your life.
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Connections
Comparing Texts
1. How are other mountains you know about similar to or different from those described in
“Mountains”?
2. Compare and contrast the descriptions of Mount Everest in “Mountains” and in “To the Top
of the World.”
3. Mountains go through many changes. What kinds of changes do people go through during
their lives?
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