Guiding Comprehension

Steps in a Process • Inferential

Go through the selection and
identify the steps in the
formation of a volcano.

Steps students include will vary,
but they should include the
following: 1. Rocks in the earth's
mantle melt; 2. The magma is
pushed up toward the earth's
crust; 3. Magma comes out of
the ground where the plates that
form the crust meet; 4. A
mountain of hardened lava and
ash forms.

Summarize • Critical

What have you learned about
volcanoes from reading this
article?

Possible response: From far
away, volcanoes can look
beautiful. Up close, they can be
very dangerous. Volcanoes are
formed when the hot magma at
the earth's core is pushed out
through the earth's crust.
Sometimes the magma oozes
out, and sometimes it explodes
out. Some volcanoes have
blown away sides of mountains
or covered entire cities.

Cause and Effect • Critical

Text to World Are earthquakes
or volcanoes common where
you live? How does this article
explain why that is?

Responses will vary. Check that
students understand that areas
near plate divisions (e.g. the
west coast of the United States)
experience more frequent
earthquakes and volcanic
activity than other areas.

Summarize When students finish reading the selection, provide this prompt: Imagine that you want to tell a friend what Volcanoes: Nature's Incredible Fireworks is about. In four or five sentences, explain its important points.

STRATEGY SELF-CHECK

Monitor and
Fix Up

Have students look back at their summaries and think about any questions they have. Then have them go back through the selection. Explain that sometimes rereading can help us better understand what we have read. After they have reread the selections, have students check their summaries for accuracy and correct them if necessary. Have them compare what they read with what they already knew about volcanoes. Use Practice Book 3.1, p. 147.

SELF-CHECK

Students can ask themselves:

Does my summary make all the points the article made?
Do I have any questions about the article?
Did I understand everything I read?

then…
use the
Reteach
lesson on
p. 399b.

If… students
have difficulty
making
comparisons
and monitoring
their
comprehension,

Compare and Contrast

Practice Book 3.1 p. 147

with | without Answers

"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
	Understand Idioms Point out the idiom blow its top on p. 393. Here, it is actually used as it was originally intended—to refer to a volcano exploding and blowing away the top of a mountain. Explain that it also has a second meaning: to become very angry. Use the expression in a sentence, for example, "My father really blew his top when I left his drill outside and it rained." Have students use it in a sentence of their own. PRACTICE LESSON VOCABULARY Students orally respond yes or no to each question and provide a reason for each answer. Can you compare a volcano to a giant chimney on a mountain? (Yes, if you think of the mountain releasing smoke and ash from its top like a house does through a chimney.) Can you see the effects of earthquakes on the earth's surface? (Yes, you can see damaged buildings, and sometimes the earth itself is torn.) Are volcanoes found beneath the earth's surface? (No, although the source of a volcano is.) BUILD CONCEPT VOCABULARY Review previous concept words with students. Ask if students have met 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