Guiding Comprehension

Compare and Contrast

• Inferential

Name two ways that the crust is different from the mantle.

The crust is thin and solid; the mantle is thick and gooey.

Vocabulary • Dictionary

Look up the words core and crust in a dictionary. How can the other definitions of these words help you remember the structure of Earth?

A core is also the middle part of an apple or pear. That makes me remember that the core is the middle of Earth. A crust is also the outside part of bread. That makes me think of the outside layer of Earth.

then…
use the vocabulary skill
instruction on
p. 389.

If… students are unable to use a dictionary to answer
the question,

Dictionary

Graphic Sources

• Inferential

Text to World On which layer do we live and work and build our houses, offices, and schools? Use the diagram to help you answer the question.

The crust.

VOCABULARY SKILL

Dictionary

TEACH

Model finding and applying the other definitions for core and crust.

MODEL I look up core in the dictionary and see that it is the hard middle of apples and pears. Apples are shaped like Earth, so I can see how the core of each can be similar. Then I look up crust. One of the definitions is the outside part of bread. Earth’s crust is its outside, so I can think of bread to remember what crust means.

PRACTICE AND ASSESS

Have students use a dictionary to identify other unfamiliar words in the selection. Tell them to make sure they choose the correct definition for multiple-meaning words.

Check Predictions Provide the following prompt: Go back to p. 384 and look at your prediction for the selection. Was your prediction correct? Revise your old prediction or make a new one about the rest of the selection.

Similes

Remind students that to compare and contrast is to find similarities and differences. Point out that a simile is a comparison of two unrelated things that are alike in one way. Similes have different forms. They can use like or as (“He slept like a baby”) or a comparative adjective and than (“Her cheeks are pinker than a rose”).

If you want to teach this selection in
two sessions, stop here.

"Volcanoes: Nature's Incredible Fireworks"
by David L. Harrison

Student Edition
Unit 3, pp. 384–393

Expository nonfiction gives facts and information. Look for facts about volcanoes as you read.

Earth is constantly moving. Volcanoes quietly erupt each day somewhere and prove there is activity inside our planet.
Earth is like a giant ball with four layers. We live on top, on the miles-deep crust. But the crust is really many huge pieces that almost fit together. Where the pieces don't exactly meet is where most volcanoes and even earthquakes happen.
The pieces that form Earth's crust are called plates. They rest on the layer beneath, called the mantle. In the mantle it is so hot that rocks can melt into sticky magma. When a big volcano erupts, magma can shoot up as red-hot lava—nature's incredible fireworks. Buried deeper still is Earth's core. The outer core is so hot that iron melts into liquid. At the very center is Earth's solid inner core.
Volcanoes erupt when fiery hot magma finds a weak spot and bubbles up. They can occur on the ocean floor. Some erupt up a chimney-like cone. Then lava cools back into rock, and they erupt again. This can happen over and over for thousands of years, until mountains are created. (The islands of Hawaii are really volcanoes.)
Or a volcano can erupt in an old volcanic mountain that looks peaceful and quiet. Mount St. Helens in the United States suddenly exploded in 1980 with tremendous force.
Most volcanoes don't make the news. They have been occurring for millions of years. Yet a very big one happened almost 2,000 years ago in Italy. Mount Vesuvius erupted and buried two cities and all their people and animals.
When magma rubs against the bottom of a plate, rocks can move and the earth trembles. Plates bump into each other so often around the Pacific Ocean that the vast area is called the Ring of Fire. Some of Earth's most serious eruptions and earthquakes have happened there.
Scientists study volcanoes so they can learn more about these powerful natural giants. They also want to be able to predict the next big blow-up.



	Close
	Activate Prior Knowledge Have students think about what they may have studied about earth science in their native language. Encourage them to explain what they know or remember, allowing them to use English and understand the text. If necessary, they may look up specific terms, such as crust, mantle, and core, in their native language using a bilingual dictionary or an online translator. Encourage them to record any new words they learn in a notebook reserved for vocabulary. PRACTICE LESSON VOCABULARY Read sentences aloud and have students fill in the blanks orally. Mountains with holes from which lava flows and rocks erupt are _________. (volcanoes) The author compares a volcano's explosion to _______. (fireworks) Sometimes the earth's surface shakes and _________. (trembles) BUILD CONCEPT VOCABULARY Review previous concept words with students. Ask if students have come across any words today in their reading or elsewhere that they would like to add to the Concept Web.

"Volcanoes: Nature's Incredible Fireworks" by David L. Harrison

"Volcanoes: Nature's Incredible Fireworks"
by David L. Harrison