CHAPTER 10
Changes in
Matter
Lesson 1
Changes of State. . .
396
Lesson 2
Physical Changes . .
406
Lesson 3
Chemical Changes. . 4 1 6
In what ways can matter change?
394
Key Vocabulary
melt
to change from a solid
to a liquid (p. 398)
More Vocabulary
evaporate, p. 399
condense, p. 400
freeze, p. 401
boil
to change from a liquid
to a gas (p. 399)
physical change
a change in the way
matter looks (p. 408)
mixture
different kinds of matter
mixed together (p. 410)
solution
when one or more kinds
of matter are mixed evenly
into another kind of matter;
a solution can be a solid, a
liquid, or a gas (p. 411)
chemical change
a change that causes
different kinds of matter
to form (p. 418)
395
Lesson 1
Changes
of State
A winter storm can bring snow and
ice. What happens to snow on a warm,
sunny day? What causes this change?
396
ENGAGE
What happens when ice
is heated?
Materials
Make a Prediction
How does ice change as it is heated?
Write a prediction.
thermometer
Test Your Prediction
Measure Place a thermometer in a cup of ice.
Measure the temperature of the ice. Record the
temperature in a table like the one shown.
plastic cup
of ice
Place the cup in a warm place, such as on
a sunny windowsill.
Measure Stir the ice and measure its
temperature every 10 minutes for the next
hour. Record the temperature in the table.
Describe how the ice changes.
Draw Conclusions
spoon
Step
Time
Temperature
Communicate How did the ice change as
it was heated? Was your prediction correct?
Infer What happened to the temperature
of the water as the ice melted? At what
temperature does ice melt?
Explore More
Step
Predict What will happen to the water as
it continues to sit in the warm place after the ice
has melted? Test your prediction and find out.
397
EXPLORE
Main Idea
Adding or removing
heat can cause matter
to change state.
Vocabulary
melt, p. 398
boil, p. 399
evaporate, p. 399
condense, p. 400
freeze, p. 401
-Glossary
at
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Reading Skill
Predict
What happens when matter
is heated?
When matter is heated, it gains energy.
Its temperature rises. At certain temperatures,
matter will change state.
Changing from a Solid to a Liquid
If you heat most solids to a high enough
temperature, they will melt. To melt is to change
from a solid to a liquid. Different kinds of matter
melt at different temperatures. Ice melts at a
lower temperature than rocks. Ice melts at
32˚F (0˚C). Rocks melt at over 1,100˚F (593˚C)!
Remember that all matter is made up of
tiny particles. In solids these particles are held
closely together. When a solid is heated and gains
energy, its particles begin to move away from
each other. They flow around each other and
are no longer held tightly together. This causes
the solid to lose its shape. It becomes a liquid.
Technology
Explore how matter changes
with the Secret Agents.
The lava flowing
from this volcano
is rock that melted
deep beneath
Earth’s surface.
398
EXPLAIN
Changing from a Liquid to a Gas
If you heat a liquid to a high enough temperature,
it will boil. To boil is to change from a liquid to a
gas. Energy from heat causes the particles in a liquid
to move faster. They spread apart. The liquid turns
into a gas.
These clothes
will dry when
the liquid
water changes
into a gas.
Liquids can also evaporate, or change into a gas,
slowly. When wet clothes are placed in the Sun, the
water in the clothes evaporates. The Sun heats water
droplets in the clothes. The water turns into a gas
and your clothes dry. The gas state of water is called
water vapor. You cannot see water vapor, but it is
part of the air.
Heating Water
solid
liquid
gas
Read a Diagram
What happens when you heat ice?
Quick Check
Clue: Arrows show a sequence.
Predict What will happen
to cheese when it is heated?
Watch how matter
changes at www.macmillanmh.com
Critical Thinking How does
a blow dryer get your hair dry?
399
EXPLAIN
What happens when
matter is cooled?
When matter is cooled, it loses energy.
Its temperature drops. At certain
temperatures, matter will change state.
Changing from a Gas to a Liquid
If you cool a gas to the right
temperature, it will condense (kuhn•DENS).
To condense is to change from a gas to
a liquid. For example, on cool mornings,
small droplets of water called dew can
appear on grass and windows. This
happens when water vapor in the air
touches cool objects and loses energy.
Particles of water vapor come closer
together. They change into drops of
liquid water.
Dew forms when water vapor
in the air cools and condenses.
Water vapor in this tiger’s breath
condenses on a cold day.
400
EXPLAIN
Changing from a Liquid
to a Solid
If you cool a liquid to the
right temperature, it will freeze.
To freeze is to change from a
liquid to a solid. The particles in
the liquid lose energy and move
slower and closer together. They
get locked into position and
form a solid. For example, when
you put liquid water into the
freezer, it loses energy. It cools to
a certain temperature and turns
into ice.
Condense Water Vapor
Observe Feel an empty plastic
cup. Does it feel wet or dry?
Does it feel hot or cold?
Record your observations.
Fill your cup with ice
cubes. Next add cold
water to the cup.
Observe Feel your cup
again. Does the cup feel
wet or dry? Does the cup
feel hot or cold? Record
your observations.
Observe Look at your cup after
five minutes. What do you notice
about the outside of the cup?
Is it wet or dry?
Infer Where did the water on
the cup come from?
When juice is cooled enough,
it will freeze and become a solid.
Quick Check
Predict What will happen to
water vapor when it is cooled?
Critical Thinking How could
you make an ice pop?
401
EXPLAIN
How is water different from
other kinds of matter?
Most kinds of matter shrink as they freeze. Their
particles get packed more closely together. They take
up less space. Yet water gets larger when it freezes.
As water freezes, its particles rearrange
themselves. They make a special pattern. Empty
spaces form between the particles. The frozen water
takes up more space than the liquid water. This is
why freezing a glass of water cracks the glass.
Ice floats in liquid water. This keeps lakes and
ponds from freezing from the bottom up. Living
things can survive under the ice.
Quick Check
Predict What would happen if you put
a plastic bottle filled with liquid water in
the freezer? Why does this happen?
Critical Thinking Describe how water
changes when it melts.
The particles in ice are
more spread out than the
particles in liquid water.
This is why ice floats.
solid water
liquid water
402
EXPLAIN
Ice, liquid water, and water vapor are all forms of water.
Visual Summary
When most solids
are heated, they melt
into liquids. When
a liquid is heated, it
changes into a gas.
When a gas cools it
usually condenses
into a liquid. When a
liquid cools it freezes
into a solid.
Think, Talk, and Write
Main Idea How can heat
change matter?
Vocabulary What happens when
a gas condenses?
Predict After a rainstorm the Sun
comes out and shines brightly. What
will happen to puddles of rainwater?
Water is a special
kind of matter. It
gets larger when
it freezes.
Critical Thinking You see drops of
water on the bathroom mirror after a
shower. What caused the water drops
to form?
Make a
Study Guide
Make a LayeredLook Book. Use
it to summarize
what you
learned about
changes of state.
Writing Link
Write a Story
Describe how your life would be
different if liquids changed into
solids when heated. For example,
it could snow when the temperature
outside was very hot.
Test Prep How is water different
from other liquids?
A Water gets larger as it freezes.
B Water gets smaller as it freezes.
C Water stays the same as it freezes.
D Water never freezes.
Math Link
Find the Difference
Ice melts at 32°F. Water boils at
212°F. How many degrees are there
between water’s melting and boiling
temperatures?
-Review Summaries and quizzes online at www.macmillanmh.com
403
EVALUATE
Inquiry Skill:
Predict
You just learned about how liquids change
to solids. Which do you think freezes faster,
salt water or fresh water? To find answers to
questions like this, scientists first predict what
they think will happen. Next, they experiment
to find out what does happen. Then, they
compare their results with their prediction.
Learn It
When you predict, you state the possible results
of an event or experiment. It is important to record
your prediction before you do an experiment. Next,
you record your observations as you experiment and
record the final results. Then you have enough data
to figure out if your prediction was correct.
Ice floats on the salt water
of Shoup Bay in Alaska.
404
EXTEND
Try It
Which do you think freezes faster,
salt water or fresh water? Predict what
will happen when you freeze fresh water
and salt water. Write your prediction on
a chart like the one shown. Then do an
experiment to test your prediction.
Materials measuring cup, water, two
plastic cups, salt, measuring spoon
Which Freezes Faster?
My Predictions
Observations
of fresh water
Pour 125 mL of water into a plastic
cup. Label this cup Fresh Water.
Observations
of salt water
Pour 125 mL of water into another
plastic cup. Add 1 tablespoon of
salt and stir with a spoon. Label
this cup Salt Water.
Results
Place both cups into the freezer.
Check them every 15 minutes.
Draw or write your observations.
Now answer these questions. Which
freezes faster, fresh water or salt water?
Was your prediction correct?
Apply It
Now that you have learned to
think like a scientist, make another
prediction. Do you predict that salt
water or fresh water will evaporate
faster? Plan an experiment to find
out if your prediction is correct.
405
EXTEND
Lesson 2
Physical
Changes
Changes take place around you all
the time. This clay is changing shape.
What objects around you change
every day? How do they change?
406
ENGAGE
How can you change matter?
Materials
Purpose
Find out some ways you can change matter.
Procedure
Make a table like the one shown below.
Object
Change
paper
Properties changed
Paper
Clay
clay
Ice cubes
ice cubes
Observe Look at each object. What
properties does each object have? How can
you change each object? Record your plan.
scissors
Experiment Change each object.
What properties does each have now?
Record the property that has changed.
Be Careful. Handle scissors carefully.
Step
Draw Conclusions
How are the objects different after you
made the changes?
Infer Do you think you changed the kind
of matter making up the object? Explain.
Explore More
Experiment What would happen if you
added a spoon of salt to a cup of water?
How would the salt and water change? How
could you remove the salt from the water?
407
EXPLORE
What are physical changes?
Main Idea
Matter looks different
after a physical change,
but it is still the same
kind of matter. You can
mix matter together
to form mixtures and
solutions.
Vocabulary
physical change, p. 408
mixture, p. 410
solution, p. 411
-Glossary
at
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Reading Skill
Draw Conclusions
Matter can change. A physical change
(FIZ•i•kuhl CHAYNJ) is a change in the way
matter looks. Tearing a sheet of paper is a
physical change. The size and shape of the
paper are different, but the paper is still paper.
Matter looks different after a physical change,
but it is still made of the same kind of matter.
A change of state is also a physical change.
When liquid water freezes, its state changes
from a liquid to a solid. The water looks
different, but it is still water.
Not all types of matter change in the same
way. If you pull on a rubber band it stretches.
When you let go, it returns to its original size.
If you pull on a metal spoon, nothing happens.
If you pull on a piece of thread, it might break.
Painting an object does not change
what the object is made of. 408
EXPLAIN
How Steel Changes
Solid steel is melted into a liquid.
The melted steel can be shaped
to make the frame of a car.
The steel hardens. Now it is a solid.
It is combined with other materials
to make a car.
The steel is now part of a car. The car
is ready to drive on the highway.
In time, the car is crushed. The steel
can be melted and used again to make
other steel products.
Read a Chart
What physical changes have happened to
the steel?
Clue: Look at how the steel has changed in
each photograph. Use the captions to help.
Quick Check
Draw Conclusions Why is a change of state
a physical change?
Critical Thinking Make a list of three physical
changes you could make to a piece of paper.
409
EXPLAIN
What happens when you
mix matter?
Another kind of physical change is a mixture
(MIKS•chuhr). A mixture is different kinds of
matter mixed together. When you pour milk
on your cereal, you are making a mixture.
In a mixture the properties of each kind of
matter do not change. The milk is still milk,
and the cereal is still cereal.
A mixture can be a combination of solids,
liquids, and gases. Vegetable soup is a mixture
of liquids and solids. Salad dressing can be a
mixture of different liquids. Clouds are a mixture
of air, dust, and water droplets.
410
EXPLAIN
Solutions can be solid.
What makes up
this mixture?
Solutions
There are many kinds of mixtures. One kind of
mixture is a solution (suh•LEW•shuhn). A solution
forms when one or more kinds of matter are mixed
evenly into another kind of matter.
Salt water is a solution. If you add salt to water,
the salt mixes evenly with the water. You cannot see
the salt, but it is still there. If the water evaporates,
the salt will be left behind.
Not all solids form solutions in liquids.
Try to mix sand with water. The sand will
just sink to the bottom. Some things will not
form solutions no matter how long you stir.
Some solutions contain no liquids at all. Air is a
solution of different gases. Brass is a solution
of several solids, including copper and zinc.
Brass is a solution
of metals. It is used
to make musical
instruments.
Quick Check
Draw Conclusions Do all kinds of
Ocean water is a mixture.
It contains many different
types of matter, including
salt, water, and oxygen.
matter form solutions with water?
Explain your answer.
Critical Thinking You cannot see
that salt is in salt water. How do
you know it is there?
411
EXPLAIN
Separating Mixtures
Mix some sand, marbles, and
paper clips together in a bowl.
Experiment Design an
experiment to separate
this mixture.
Observe Were you able to
completely separate the
mixture? How do you know?
Experiment How could you
separate a mixture of sugar
and water?
How can mixtures
be separated?
Some properties help you separate
mixtures. These properties include
size, shape, and color. One way to
separate a mixture is to pick out each
different type of matter. In a mixture
of spaghetti and meatballs, you can
pick out the meatballs.
Another way to separate a mixture
is by evaporation. Leave a solution
of salt and water in a warm place. As
the water evaporates, the salt is left
behind. The photos below show some
other ways to separate mixtures.
Quick Check
Draw Conclusions How can
you separate peas from carrots?
Critical Thinking List some
ways to separate sand from salt.
Objects that float, such
as these cranberries,
can be separated from
objects that sink. 412
EXPLAIN
Filters separate
mixtures by size. Magnets separate
certain metals from
other objects. Visual Summary
Think, Talk, and Write
Physical changes
cause matter to
look different. The
kind of matter stays
the same.
Main Idea Describe and explain
A mixture is a
combination of
two or more types
of matter.
Draw Conclusions A sculptor
carves a statue out of a rock. Is this a
physical change? How do you know?
three types of physical changes.
Vocabulary What is a mixture?
Some properties can
help you separate a
mixture.
Critical Thinking How could you
separate plastic paper clips from
metal paper clips?
Make a
Study Guide
Test Prep Noodles and broth could
Make a Trifold
Book. Use it to
summarize what
you learned about
physical changes.
Math Link
Sort and Classify Materials
What materials dissolve in water?
Try mixing several materials, such as
salt, flour, sugar, soil, and cooking
oil, with water. Then classify the
materials into groups to show which
dissolve and which do not. Make a
chart to show your results.
be separated by
A heating in an oven.
B boiling in a pot.
C filtering.
D freezing.
Art Link
Experiment with Color
Cut a circle out of a coffee filter. Use
a black marker to draw a spot in the
center of the filter. Put the filter on
a plate. Add a few drops of water to
the spot. Watch what happens. Why
do you think this happens? What
does this tell you about ink?
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413
EVALUATE
Did you use something made of
metal today? You might have if you ate
breakfast with a spoon or rode your
bike to school. Both are made of metals.
Metals come from the earth. Metals
are found in ores. Ores are rocks that
have useful minerals. Some of these
minerals contain metals, such as silver
or copper. Ores can be found in all kinds
of places, from volcanoes to river valleys
to mountains.
An ore is usually mined from the ground.
Then it is crushed into powder. Magnets,
oil, chemicals, and streams of water can
be used to separate the minerals from the
powdered rock. Later, these minerals
are heated to high temperatures to
draw out the metals inside them.
Once separated, the metals
can be mixed with other
metals. Then the metals are
used to create products, such
as the spoon or bicycle you
used today.
414
EXTEND
Science, Technology, and Society
rock crusher
Infer
When you infer
you use what you
already know
you use facts in
the article
you form new ideas
Write About It
Infer Read the article with a partner. Use what you
know and what you read in the article to answer this
question. Why do you think it is important for people
to recycle metals? Write a paragraph to share your ideas.
-Journal Write about it online
at www.macmillanmh.com
415
EXTEND
Lesson 3
Chemical
Changes
Have you ever baked a cake? Why doesn’t
a cake taste like the ingredients it is made
from? What happens to the ingredients to
make them taste different?
416
ENGAGE
How can matter change?
Materials
Make a Prediction
How do flour and baking soda change when
each is mixed with vinegar? Write a prediction.
Test Your Prediction
vinegar
flour
Be Careful. Wear goggles.
baking
soda
Observe List the properties of the
vinegar, flour, and baking soda.
Measure Use a funnel to put 2
tablespoons of flour in one balloon.
Add 50 mL of vinegar to a plastic bottle.
goggles
funnel
Experiment Carefully, put the balloon
over the bottle’s opening without letting
any flour fall into the bottle. After you
attach the balloon, raise it up so the
flour goes into the bottle. Record your
observations.
measuring cup and spoons
Repeat steps 2 and 3 using the second
balloon and baking soda instead of flour.
Draw Conclusions
2 balloons
Did your results match your prediction?
Explain your answer.
Infer What do you think caused the
differences in the balloons?
2 plastic
bottles
Step
Explore More
Experiment What might happen to the
balloon if you add two tablespoons of baking
soda and 50 mL of water to a container? Try
it and find out.
417
EXPLORE
What are chemical changes?
Main Idea
Chemical changes cause
different kinds of matter
to form.
Vocabulary
chemical change, p. 418
-Glossary
at
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Reading Skill
Infer
You may have seen an apple turn brown
or a burning log change into ash and smoke.
Both are examples of a chemical change
(KEM•i•kuhl CHAYNJ). A chemical change is a
change that causes different kinds of matter
to form. The properties of the new matter are
different from those of the original materials.
Chemical changes happen every day. Your
body uses chemical changes to break down
the food you eat. Green plants use the Sun’s
energy to change carbon dioxide and water
into food and oxygen. Cooking also uses
chemical changes. Cake batter changes when
you bake it. You know that it has changed
because it feels and tastes different.
A Chemical Change
unripe
ripe
overripe
A chemical change happens when fruit ripens.
As bananas ripen, they change color. They also
become softer and sweeter.
Read a Diagram
How have the bananas in these
photographs changed?
Clue: Compare the three photographs
to find differences.
418
EXPLAIN
Not all chemical changes are
useful. A car made out of iron may
rust. Rust is very different from
iron. It is weaker and it peels. Food
spoils as a result of chemical changes.
Materials in food can break down
and form new materials. When this
happens food may change color or
smell bad.
Quick Check
Infer Is it a physical or chemical
change when milk spoils? Why?
Critical Thinking Why are
chemical changes important to
living things?
A Chemical Change
Observe Look closely at
some pennies. Make a list
of their properties.
Place 1 teaspoon of salt in a
bowl. Add 150 mL of vinegar.
Stir until the salt dissolves.
Experiment Dip a penny
halfway into the
liquid. Slowly
count to 20 as
you hold the coin
there. Then remove
the penny. Compare the half
you held with the half that was
in the liquid.
Infer What caused the change
in appearance?
Water and oxygen
caused the iron in
this train to rust. 419
EXPLAIN
What are the signs of a
chemical change?
Sometimes a chemical change happens
when different materials are put together.
Certain signs can show that a chemical
change has happened. Here are a few.
Light and Heat
A burning log changes into carbon
dioxide gas and ash. As the log burns, it
releases light and heat. The light and heat
are signs of a chemical change.
Heat and light are
two signs of a
chemical change.
Formation of Gas
The formation of a gas can be a sign of a
chemical change. When you add baking soda
to vinegar, carbon dioxide gas forms. As this
gas escapes from the liquid, bubbles form.
Color Change
Sometimes a color change shows that
a chemical change has happened. The Statue
of Liberty used to be the same color as
a penny. It turned green as a result
of a chemical change.
Quick Check
Infer Is a burning match a
physical or chemical change?
How do you know?
Critical Thinking Is sugar
dissolving in water a physical
or chemical change? Explain.
420
EXPLAIN
These bubbles tell
you a chemical
change is occurring.
The Statue of Liberty
got its green color from
a chemical change. Visual Summary
Chemical changes
cause different kinds
of matter to form.
Think, Talk, and Write
Main Idea List three things that
may tell you a chemical change
has occurred.
Vocabulary What is a chemical
You observe chemical
changes every day.
change? Give an example.
Infer Two clear liquids are combined.
Bubbles form. What kind of change
might have happened? Explain.
Light and heat,
formation of a gas,
and a color change
are signs of a
chemical change.
Critical Thinking Mrs. Hall wiped a
discolored pot with a special cleaner.
The pot returned to its original color.
What happened?
Make a
Study Guide
Make a Trifold
Book. Use it to
summarize what
you learned
about chemical
changes.
Test Prep Which is a chemical
change to a piece of paper?
A folding
B cutting
C tearing
D burning
Math Link
Solve a Problem
A log takes one hour to burn down
to ash. A banana turns brown and
mushy in four days. How many
hours did the longer chemical
change take?
Social Studies Link
Conduct Research
Bread is made differently in other
countries. Different ingredients
make different chemical changes.
Research how bread is made in
other countries.
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421
EVALUATE
Materials
chalk
Structured Inquiry
How can physical and chemical
changes affect matter?
Form a Hypothesis
hand lens
How will breaking chalk change the chalk? How
will adding vinegar to the chalk change it? Write
a hypothesis.
Test Your Hypothesis
black construction
paper
Observe Break a piece of chalk in half.
Use a hand lens to look at the broken end of
the chalk. Record your observations. Is this
a chemical or physical change?
Experiment Rub one
vinegar
Step
of the chalk pieces on a
piece of black paper. Using
the hand lens look at the
chalk on the paper. Record
your observations. Is this a
chemical or physical change?
Experiment Use a dropper to add
dropper
one drop of vinegar to the chalk on the
black paper. Record your observations.
Is this a chemical or physical change?
Draw Conclusions
Interpret Data What did you
observe? Which changes were
physical changes? Was there
a chemical change?
Step
422
EXTEND
Infer Describe what happened to the chalk when
you added the vinegar. What caused this to happen?
Communicate Use your observations to write your
own definitions of chemical and physical change.
Guided Inquiry
Open Inquiry
What are the signs of
a chemical change?
Form a Hypothesis
How can you tell a chemical change
has happened? Write a hypothesis.
What else would you like to know
about physical and chemical
changes? Come up with a question
to investigate. For example, how
does iron rust? Design an experiment
to answer your question.
Test Your Hypothesis
Design an experiment to investigate
chemical changes. Use the materials
shown. Write the steps you plan
to follow. Record your results and
observations.
Remember to
follow the steps of
the scientific process.
Ask a Question
Materials
Form a Hypothesis
plastic
cups
spoon
milk
Test Your Hypothesis
Draw Conclusions
iron
wool
vinegar
baking
soda
Draw Conclusions
What changes did you observe?
Did your experiment support your
hypothesis? Why or why not?
423
EXTEND
CHAPTER 10 Review
Visual Summary
Fill each blank with the best term
from the list.
Lesson 1 Adding
or removing heat
can cause matter to
change state.
chemical change, p. 418
Lesson 2 Matter
looks different after a
physical change, but
it is still the same kind
of matter.
freeze, p. 401
Lesson 3 Chemical
changes cause
different kinds of
matter to form.
condense, p. 400
evaporate, p. 399
mixture, p. 410
melt, p. 398
physical change, p. 408
solution, p. 411
1. When you mix spaghetti and
meatballs together, you make
a
.
Make a
Study Guide
2. Tearing a sheet of paper is
a
.
Glue your lesson study guides to a
piece of paper as shown. Use your
study guide to review what you
have learned in this chapter.
3. If you
a solid.
a liquid, it becomes
4. A change that causes different kinds
of matter to form is a
.
5. To change from a liquid to a gas
slowly is to
.
6. When you mix salt with water you
make a
.
7. To change from a solid to a liquid
is to
.
8. If you cool a gas to the right
temperature, it will
, or turn
into a liquid.
424
-Review Summaries and quizzes online at www.macmillanmh.com
Answer each of the following in
complete sentences.
9. Infer What kind of change occurs
when you toast bread? What kind
of change occurs when butter
melts on a piece of toast? Explain
your answer.
10. Expository Writing Describe
what happens to water as
it freezes.
Act It Out!
With a partner, act out one important
term or idea from this chapter. For
example, you may choose a term such
as melt. You may not speak during
your skit.
Present your skit to the class. Then let
other students guess the term.
What information about your term
or idea did you show? How did you
show it?
11. Predict It is a warm, sunny day.
You leave a bar of chocolate on the What details helped you guess other
window sill. How do you think it will
pairs’ terms and ideas?
change? Can you change it back?
12. Critical Thinking You add sugar
to a glass of lemonade and stir
it. You cannot see the sugar
anymore. The lemonade tastes
sweet now. What kind of mixture
is this? How do you know?
13. Study the photograph. In what
two states of matter is water
shown? Describe how they
are different.
1. Which of the following BEST
describes what happens when
a log burns?
A A chemical change is taking place.
B The logs are becoming a liquid.
C The logs are getting bigger.
D Smoke is boiling.
14. In what ways can matter
change?
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Environmental Chemist
Do you like helping keep plants and
animals healthy? Are you concerned
with keeping the environment clean?
If so, then you might like to be an
environmental chemist.
An environmental chemist is a kind of
scientist. These scientists help keep the
water, land, and air free of pollution.
Pollution can hurt plants, animals, and
people. Environmental chemists protect
living things by helping clean up pollution.
Environmental chemists also show people
how to reduce pollution.
To become an environmental chemist,
you should begin learning about the
environment where you live. Start a
recycling program in your home or at
school to reduce waste. You could also join
a group that helps protect the environment.
This scientist is collecting
data on water pollution.
Here are some other
Physical Science careers:
• carpenter
• lab technician
• chemical engineer
• pharmacist
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This chemist is testing to
see how much oil is left
on a beach after a spill.
-Careers at www.macmillanmh.com