Guiding Comprehension

Compare and Contrast

• Literal

In the last sentence of the first paragraph on p. 386, to what does the author compare volcanoes?

Fireworks.

then… use the skill
and strategy instruction
on p. 387.

If… students are unable to recognize
the comparison,

Compare and Contrast

Sensory Words • Critical

Which words in the selection help you see, hear, and feel what the author is describing?

Fiery, scalding hot, gritty, blast, dark, and roar.

Find information on volcanoes, especially currently active volcanoes, such as in the Hawaiian Islands or Mount St. Helens in Washington.

SKILLS

STRATEGIES IN CONTEXT

Compare and
Contrast

TEACH

Explain that to compare and contrast is to look for similarities and differences.
Tell students that sometimes, but not always, authors use clue words such as like or as to show comparisons.
Model identifying the comparison on p. 386, paragraph 1.

MODEL I read that “from far off [volcanoes] look like beautiful fireworks.” I see the word like. That’s one of the clue words. I think the author is comparing volcanoes to fireworks.

PRACTICE AND ASSESS

Have students reread pp. 386–387 and find three more comparisons the author makes. (Possible responses: “looks like sparks,” “heavier than elephants,” some volcanoes explode while others just let lava escape.) To assess, check that students have identified the clue word that pointed them to the comparison.

"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
	Build Background Help students recognize words that are important to the selection, such as erupt, ashes, geysers, and scalding. When a volcano erupts, lava and particles explode out of an opening in the ground. It is so hot, it burns, or scalds, everything and creates ashes, or what is left of burnt objects. Geysers are similar to volcanoes—they are eruptions of hot gases and steam from an opening in the earth. Have students describe the photos on pp. 386–387 using these terms. World Communities Since a major eruption in A.D. 79, which covered several cities, including Pompeii and Herculaneum, Mt. Vesuvius in southern Italy has gone through several stages of eruption and silence. It last erupted in 1944. Despite the possibility of another eruption, the area around Vesuvius is a busy, populated area. Several cities are nearby, and small towns and villages dot the slopes of the mountain, where citrus fruits and grapes for wine grow.

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

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