by Lorrie Oestreicher
Scott Foresman Science 3.11
Genre Comprehension Skill Text Features Science Content
Nonfi ction Cause and Effect Captions
Glossary
Changes in Matter
ISBN 0-328-13838-X
Vocabularychemical change
mixture
physical change
solution
states of matter
What did you learn?1. What are three states of matter?
2. Why is cutting paper a physical change?
3. Is a salad a mixture? Why or why not?
4. In this book you read about dissolving salt in water. Write to explain why it is a mixture and how you could demonstrate this. Use details from the book as you write.
5. Cause and Effect What causes water to turn into ice? What is the effect on the state of matter?
Photographs: Every effort has been made to secure permission and provide appropriate credit for photographic material. The publisher deeply regrets any omission and pledges to correct errors called to its attention in subsequent editions. Unless otherwise acknowledged, all photographs are the property of Scott Foresman, a division of Pearson Education. Photo locators denoted as follows: Top (T), Center (C), Bottom (B), Left (L), Right (R) Background (Bkgd)Opener: (Bkgd) John Gillmoure/Corbis, (Bkgd) The Image Bank/Getty Images; Title Page: Garry Black/Masterfile Corporation; 2 Robb DeWall; 6 Garry Black/Masterfile Corporation; 10 Stone/Getty Images; 12 (BR, BL) DK Images; 13 (CL) Richard Megna/Fundamental Photographs, (CR) Dave King/Pitt Rivers Museum/University of Oxford/DK Images; 14 Stone/Getty Images; 15 Doug Scott/Age Fotostock
ISBN: 0-328-13838-X
Copyright Pearson Education, Inc.
All Rights Reserved. Printed in the United States of America. This publication is protected by Copyright and permission should be obtained from the publisher prior to any prohibited reproduction, storage in a retrieval system, or transmission in any form by any means, electronic, mechanical, photocopying, recording, or likewise. For information regarding permissions, write to: Permissions Department, Scott Foresman, 1900 East Lake Avenue, Glenview, Illinois 60025.
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Changes in Matterby Lorrie Oestreicher
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What are physical changes in matter?Making a Physical Change
Workers are carving this mountain into a statue of
the Native American leader Crazy Horse. They must
blast away and hammer bits of rock to do this.
The workers are causing a physical change to
the mountain. A physical change is when matter
changes the way it looks but does not become a new
kind of matter. This mountain looks different. Its
shape has changed. But it is still a solid mountain.
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Some Ways to Cause Physical ChangeThe clothes and paper in these pictures have gone
through physical changes. The clothes were folded.
The paper was cut.
One kind of physical change is when matter
changes form, or state. States of matter are the
different forms matter can have. They are solid, liquid,
and gas. The state of matter can change. But the kind
of matter stays the same.
Folding clothes causes a physical change. Cutting paper causes
a physical change.
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Water can change its state of matter. Freeze a cup
of water. It turns into ice. It changed from a liquid to
a solid. The state changed, but the kind of matter did
not. Water and ice are the same kind of matter. If you
melt the ice, it is still water. Its state changed from a
solid back to a liquid.
This water is a solid.
This water is a liquid.
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Changes in temperature can cause matter to
change its state. If you boil water, its state changes.
It evaporates. That means it changes into a gas called
water vapor. A physical change takes place. The gas
is still a form of water. But you cannot see it. The
water particles are far apart in the air. The water
has changed state. But it has not become a new
kind of matter.
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Ice is water in a solid state. It can change to a
liquid. Hold an ice cube in your fist. The particles in
a solid vibrate in place. The heat from your hand
changes it. The heat makes the particles slide past
one another. You feel water drip from your hand. A
physical change takes place. But the kind of matter is
still the same.
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What are some ways to combine matter?Mixtures
Each coin you see below is made up of matter.
Putting different coins together makes up a mixture.
A mixture is made of two or more kinds of matter
that are placed together. There can be different
amounts of each kind of matter in a mixture.
In mixtures, the matter does not change into new
matter. You can separate each kind of matter from
the others.
A magnet can help separate this mixture of sand and iron.
How many of each type of coin make up this mixture?
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Some mixtures are very easy to separate. The coins
are easy to separate. A strainer can help separate
some mixtures. The bigger matter stays in the strainer.
The smaller matter passes through the holes. A sand
and iron mixture is harder to separate. A magnet can
pull the iron out. The sand is left behind.
A strainer helps separate the parts of this marble and sand mixture.
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SolutionsMix lemonade powder and water together. The
lemonade powder will look as if it has disappeared.
But it is still there. Its particles have just become
too small for you to see. The powder has dissolved,
or broken down, in the water. It is now a solution.
A solution forms when one or more substances
dissolve in another. It is a kind of mixture. You
cannot see the powder. But you know it is there
when you taste the lemonade.
There are many kinds of solutions. Soda is a
solution. Carbon dioxide gas and other substances
are dissolved in water to make soda.
The carbon dioxide gas dissolved in this soda is escaping.
This glass of lemonade is a solution.
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Solutions can be separated since they are mixtures.
Salt dissolves in water. You can separate this mixture if
you boil the salt water. The water evaporates. The salt
is left.
Both the lemonade and the salt dissolved in water.
But even these changes are just physical changes. The
kind of matter in each solution is still the same.
Straining doesnt separate the salt from salt water.
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What are chemical changes in matter?Forming Different Materials
Have you ever watched bread being made? It starts
as a mixture. Flour, water, baking powder, and other
ingredients are mixed in a bowl. After it is baked, you
have bread. Baking the bread in an oven causes a
chemical change. During a chemical change, one
kind of matter changes into a different kind of matter.
The heat of the oven causes a new substance to form.
Bread is the result.
Baking bread causes a chemical change.
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Chemical changes can happen quickly or slowly.
Fire changes paper or wood into ashes. It takes only
minutes. Rust forms on an iron chain very slowly
over time. The iron changes into rust. A new kind of
matter forms.
You cannot often get the original matter back after
it has gone through a chemical change. You cannot
easily change the rust back into iron. You cannot
change the ashes back into paper. You cannot change
bread back into its ingredients.
Rusting is a slow chemical change.
Burning is a fast chemical change.
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Using Chemical Changes
We use chemical changes every day. When we eat
food, chemical changes take place. As the food moves
through your body, it changes. It gives your body
energy. It helps you grow.
Cars burn gasoline when they run. The chemical
change sends energy through the car engine.
Chemical changes help make things easier to do.
Soap causes chemical changes that remove stains.
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Another chemical change lets you use your CD
player. You push the buttons to play it. Chemicals
combine inside the batteries. New
