Sound physical science

Physical Science

by Timothy Sandow

Genre

Nonfiction

Comprehension Skill

Compare and
Contrast

Text Features

•
•
•
•

Captions
Labels
Diagram
Glossary

Science Content

Sound

Scott Foresman Science 3.14

ISBN 0-328-13847-9

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Vocabulary

What did you learn?

compression wave

1. How is sound made?

pitch

2. Describe the two ways stringed instruments
are played.

vibration

Sound

by Timothy Sandow

3. Explain how your ears help you hear.

Illustrations: 7, 14 Jeff Mangiat
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: ©Jake Rajs/Getty Images; Title Page: ©DK Images; ©Lynn Stone/Index Stock Imagery; 2
©Joseph Sohm/ChromoSohm Inc./Corbis; 4 (CL, BR) ©DK Images; 5 Getty Images; 6 Getty Images,
8 Getty Images; 9 (CL, CC, BL) Getty Images; 11 ©Robert Brenner/PhotoEdit; 12 ©P. Freytag/Zefa/
Masterfile Corporation; 13 ©Scott Tysick/Masterfile Corporation; 15 (CL) ©Mark Tomalty/Masterfile
Corporation, (CC) ©Christiana Carvalho-Frank Lane Picture Agency/Corbis, (BR) ©DK Images, (BL)
Stone/Getty Images

ISBN: 0-328-13847-9
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.
3 4 5 6 7 8 9 10 V010 13 12 11 10 09 08 07 06 05

4.

In this book you have read
about vocal cords and the pitch of your voice.
Write to explain how their relationship works.
Use details from the book.

5.

Compare and Contrast How do people
make sounds? How do animals make sounds?

Compare and contrast the ways people and
animals make sounds.


What causes sounds?
Take a walk in the city. Cities are noisy. Car horns
honk. Buses and garbage trucks roar by. People talk

Sounds are everywhere. Some sounds you hear
may hurt your ears. You may like other sounds. Each
sound you hear is different. Sounds are also alike in
some ways.

on the street. It is much quieter in the country. Birds
chirp. Cows moo. Water trickles in a creek.

Noisemakers are sometimes
used on New Year’s Eve.
Do you like the sounds they
make?

2

3


The Causes of Sound
Sound happens when matter moves back and forth

Hitting or Plucking to Make Sound

Some instruments make sounds when you hit them.

very quickly. This movement is called a vibration.

They are called percussion instruments. Drums are

There must be movement to make sound.

percussion instruments. Drums are played with rubber

The instruments pictured make sounds. They can

hammers, wooden sticks, brushes, or your hands. If

make high sounds. They can make low sounds. Pitch

you tap a drum lightly, you hear a soft sound. Hitting

is how high or low a sound is. Objects that vibrate

the drum harder makes a stronger vibration. This

slowly make a low-pitched sound. Objects that vibrate

makes a louder sound.

quickly make sounds that have a higher pitch.

You must hit or shake
a tambourine to make

a sound.

The blocks on this
instrument vibrate
when they are hit with
a rubber hammer.

These drums are different shapes
and sizes. Each one makes a
sound with a different pitch
when struck.

4

5


Stringed instruments are played in two ways. You
can pluck the strings. Or you can rub a bow across

Using Air to Make Sound
The sound of your voice is made by vibrations in

them. Both ways make sounds. The strings are

your windpipes. When air from your lungs passes

different sizes. They can be long or short and thick

between your vocal cords, they vibrate. You can speak

or thin. Some are stretched tighter than others. Long,

and sing because your vocal cords vibrate. When you

thick strings make a lower-pitched sound. Short,

speak, your cords tighten. The tighter they get, the

thin, tight strings make faster vibrations. They make

higher the pitch of your voice.

higher-pitched sounds.
Your vocal cords are
two pairs of thin tissue
in your windpipe.

Have you ever heard a
harp before? The strings
of this harp must be
plucked to vibrate.

6

7


A wind instrument’s sound comes from vibrating air

Some wind instruments use reeds. A reed is a thin

inside it. Blow into a trumpet. Your lips vibrate against

piece of wood. It is attached to the mouthpiece. When

the mouthpiece as you blow. This makes the air inside

a person blows on a reed, it vibrates. The vibration

the trumpet vibrate. It also makes sound.

makes the air inside the wind instrument vibrate.

You can change the pitch of the trumpet’s sound

The vibrating air makes a sound. If you press the keys

in two ways. Change how your lips vibrate. Or

of the wind instrument, you can change the pitch of

press on the valves of the trumpet. Pressing on the

the sound.

valves changes how long the air column is inside
the trumpet.

All three of these wind

instruments use reeds.

Clarinet

Saxophone
Do you know how to
play a trumpet?

Harmonica

8

9


Sound waves travel through matter. Some of the

How does sound travel?

particles that make up matter get squeezed. Other

What are sound waves?

particles are spread apart. The particles of matter take

A bell rings. Its vibrations move in the air. Some air

turns being squeezed and spread out. The length of a

particles are spread out. Others are squeezed together.

sound wave can be measured. We measure from the

The particles take turns doing this. This allows the

center of one squeezed area to the center of the next.

bell’s vibrations to move between these particles. This
movement makes a wave called a compression
wave. Sound waves are compression waves.

Sound travels as
waves in the air.

Wavelength
Sound waves from a jackhammer have lots
of energy. If you were standing nearby, you
would hear a very loud sound. Sound waves
lose energy as they move away. Farther
away, the sound would not be as loud.

10

11


Sound and Matter
You hear sound only when it travels through matter.

Echoes are sound waves that hit something and

bounce back. Scientists use sound waves and echoes

Sound can travel through solids, liquids, and gases.

to study the ocean. A ship sends out a sound wave.

The speed of a sound wave is different in each kind

When the sound wave hits the bottom of the ocean, it

of matter.

bounces back. Scientists measure how long the sound

The gases of air have particles that are far
apart. Sound travels slowly through gases. Liquid

wave takes to bounce back. Then they can figure out
how deep the ocean is at that spot.

particles are closer together. Sound travels more
quickly through a liquid than a gas. Solid particles
are closer together than gases or liquids. Sound travels
fastest through solids.
Sound travels at about
1,530 meters per second
in water. Some whales
can make sounds that
can be heard up to 160
kilometers away.

Speed of Sound
Material

Speed
(meters per second)

Solid—Steel

5,200

Liquid—Seawater

1,530

Gas—Air

340

Light travels faster than sound.
That is why you may see fireworks
before you hear them.

12

13


The Ear

Many animals have vocal cords like people do.

We hear sounds with our ears. The outer ear catches

They make sounds when their vocal cords vibrate.

sound waves. The waves travel inside the ear to the

Dogs bark. Cows moo. Some animals make sounds

eardrum. When the sound waves hit the eardrum,

that do not use vocal cords. Bees and mosquitoes

they make it vibrate. The vibrating eardrum makes

make buzzing sounds when their wings vibrate.

little bones vibrate. The little bones touch the shell-like

Bats send out sounds people cannot hear. The

inner ear. It is filled with liquid and tiny hairs. The

sounds are high-pitched and bounce off insects.

vibrating little bones make the tiny hairs move. The

The sounds return to the bats’ ears. This helps the

hairs are connected to nerves. The nerves carry signals

bats find their food.

to the brain. The brain recognizes the signals. Then we
know what we are hearing.

Many insects make sounds by
rubbing body parts together.

Little bones

Eardrum

Outer ear
Chimpanzees grunt,
bark, squeak, scream,
and even laugh.

Inner ear

14

Zebras make sounds
by vibrating their vocal
cords, lips, and nostrils.

15

Glossary
Vocabulary

What did you learn?

compressionwave
wave
compression

the wavelike movement of

pitch

particles squeezing together

vibration

and spreading out again

pitch

how high or low a sound is

vibration

the back-and-forth movement
of matter

Illustrations: 7, 14 Jeff Mangiat
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: ©Jake Rajs/Getty Images; Title Page: ©DK Images; ©Lynn Stone/Index Stock Imagery; 2
©Joseph Sohm/ChromoSohm Inc./Corbis; 4 (CL, BR) ©DK Images; 5 Getty Images; 6 Getty Images,
8 Getty Images; 9 (CL, CC, BL) Getty Images; 11 ©Robert Brenner/PhotoEdit; 12 ©P. Freytag/Zefa/
Masterfile Corporation; 13 ©Scott Tysick/Masterfile Corporation; 15 (CL) ©Mark Tomalty/Masterfile
Corporation, (CC) ©Christiana Carvalho-Frank Lane Picture Agency/Corbis, (BR) ©DK Images, (BL)
Stone/Getty Images

ISBN: 0-328-13847-9
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.
3 4 5 6 7 8 9 10 V010 13 12 11 10 09 08 07 06 05

16

1. How is sound made?
2. Describe the two ways stringed instruments
are played.
3. Explain how your ears help you hear.
4.

In this book you have read

about vocal cords and the pitch of your voice.
Write to explain how their relationship works.
Use details from the book.

5.

Compare and Contrast How do people
make sounds? How do animals make sounds?
Compare and contrast the ways people and
animals make sounds.