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Pumice: The Rock That Floats on Water

5th grade nonfiction passage about pumice: 201 words, six questions, an answer key and vocabulary.

5th grade nonfiction pumice 201 words

Pumice: The Rock That Floats on Water

Most rocks sink the moment you drop them into a pond. Pumice is different. This light gray stone can bob on the surface of water like a cork. It even feels odd in your hand, because it is rough, scratchy and surprisingly light.

Pumice is born in a volcano. Deep underground, melted rock called magma holds a lot of dissolved gas. When the volcano erupts, the magma shoots upward, and the pressure on it drops quickly. The gas expands into thousands of bubbles, just as a soda fizzes when you open the bottle.

Then the froth cools so fast that it hardens before the bubbles can escape. The result is a rock full of tiny holes. Because so much of it is trapped air, pumice weighs far less than most stone of the same size, and that is why it floats.

Pumice has many uses. Pieces of it can be ground into a gentle powder or used as a scrubbing stone for rough skin. Gardeners mix crushed pumice into soil so that roots can find air and water.

Sometimes after an eruption near the sea, floating pumice washes across the ocean in great rafts. Small animals sometimes ride along on them.

Questions

  1. What makes pumice different from most rocks? in the text

  2. Where does pumice come from? in the text

  3. What happens to the gas in magma when a volcano erupts? in the text

  4. Why does pumice float? think about it

  5. How do gardeners use crushed pumice? in the text

  6. Why does the passage compare an eruption to opening a soda? think about it

Words to know

pumice
a light rock full of tiny air holes
magma
hot melted rock beneath the earth
erupts
bursts out with force, like a volcano
pressure
the force of something pushing on something else
froth
a mass of small bubbles
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One passage, three levels

The same topic and facts written three ways, so a mixed class can read and talk about one text. Each group’s sheet shows only a shape; the key says which is which.

● Easier · 195 words · Flesch-Kincaid grade 3.6

Most rocks sink when you drop them in a pond. Pumice is different. This light gray stone can float on water like a cork. It feels odd in your hand, too. It is rough and scratchy, and it is very light.

Pumice is born in a volcano. Deep under the ground, melted rock called magma holds a lot of gas. When the volcano erupts, the magma shoots up, and the pressure on it drops fast. The gas grows into thousands of bubbles, just like a soda fizzes when you open the bottle.

Then the froth cools so fast that it hardens before the bubbles can get out. The rock is full of tiny holes. Much of it is trapped air, so pumice weighs far less than most stone of the same size. That is why it floats.

People use pumice in many ways. It can be ground into a soft powder or used as a scrubbing stone for rough skin. Gardeners mix crushed pumice into soil so roots can find air and water.

After an eruption near the sea, floating pumice can wash across the ocean in big rafts. Small animals sometimes ride on them.

▲ This passage · 201 words · Flesch-Kincaid grade 5.4

Most rocks sink the moment you drop them into a pond. Pumice is different. This light gray stone can bob on the surface of water like a cork. It even feels odd in your hand, because it is rough, scratchy and surprisingly light.

Pumice is born in a volcano. Deep underground, melted rock called magma holds a lot of dissolved gas. When the volcano erupts, the magma shoots upward, and the pressure on it drops quickly. The gas expands into thousands of bubbles, just as a soda fizzes when you open the bottle.

Then the froth cools so fast that it hardens before the bubbles can escape. The result is a rock full of tiny holes. Because so much of it is trapped air, pumice weighs far less than most stone of the same size, and that is why it floats.

Pumice has many uses. Pieces of it can be ground into a gentle powder or used as a scrubbing stone for rough skin. Gardeners mix crushed pumice into soil so that roots can find air and water.

Sometimes after an eruption near the sea, floating pumice washes across the ocean in great rafts. Small animals sometimes ride along on them.

■ Harder · 214 words · Flesch-Kincaid grade 8.1

Nearly every rock sinks the instant it is dropped into a pond, but pumice behaves quite differently. This pale gray stone is capable of bobbing on the surface of water like a cork. It even feels peculiar in your hand, because it is rough, scratchy and astonishingly light.

Pumice is born inside a volcano. Deep underground, molten rock called magma holds a considerable amount of dissolved gas. When the volcano erupts, the magma surges upward, and the pressure bearing down on it falls abruptly. The gas expands into thousands of bubbles, just as a soda fizzes when the bottle is opened.

The froth then cools so swiftly that it hardens before the bubbles have a chance to escape. The result is a rock riddled with tiny holes. Because so much of it consists of trapped air, pumice weighs far less than most stone of comparable size, which explains why it floats.

Pumice has numerous practical uses. Pieces of it can be ground into a gentle powder or used as a scrubbing stone for rough skin. Gardeners blend crushed pumice into soil so that roots can reach both air and water.

Occasionally, after an eruption near the sea, floating pumice drifts across the ocean in enormous rafts, and small animals sometimes ride along on them.

Download as one PDF

How to use it

  1. Press Read it big (or B) to put the text on the projector, or Full screen (F) to fill the whole screen.
  2. Ask the questions one at a time and use Show answer when the class has decided. A shows or hides every answer.
  3. Print student copy for the class, or Print with answers for yourself.

Ideas for class

  • Before reading, put pumice, magma, erupts, pressure and froth on the board with their meanings from the Words to know section and have students predict what the text will be about.
  • Read it aloud once while students follow along, then have them reread it alone or with a partner. At a calm 100 words a minute it takes about 2 minutes to read aloud.
  • Use the Read it big button (or B) to put the text on the projector, and Show answer on one question at a time so the class commits to an answer first.
  • Question 4 asks the reader to infer. Ask students to point to the words in the passage that led them to their answer.
  • Ask students to write one question the passage did not answer, then look for the answer in a book or on a classroom screen.
  • Print the student copy for independent work and keep the answer-key copy for yourself.

Related

Questions

What reading level is "Pumice: The Rock That Floats on Water"?

It was written for 5th grade. It has 201 words and works out to a Flesch-Kincaid grade level of about 5.4. That is a formula's estimate from sentence length and syllables, and it is not a Lexile or a guided reading level, so check it against your students.

What do the questions ask?

There are six. 4 ask for something the text says directly and 2 ask the reader to work something out from clues. Each has an answer in the key, and the answers are written as a teacher would accept them, not as the only possible wording.

How long does it take to read?

About 2 minutes read aloud at 100 words a minute. For a one-minute fluency check, paste it into the fluency timer and use the word count.

Can I print it?

Yes. Print student copy gives the passage, the questions with lines to write on, and the word meanings. Print with answers gives the same page with the answers filled in. Both are made in your browser.

Is this passage from a published book?

No. It was written for Peabody Teach, so there is no book to buy and no login to read it.

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