Scott Foresman Science, Grade 3, Leveled Readeralarm clock ring? What do you eat for breakfast? Your...

Scott Foresman Science 3.14

Genre Comprehension Skill Text Features Science Content

Nonfi ction Compare and Contrast

• Captions

• Labels

• Diagrams

• Glossary

Sound

ISBN 0-328-13848-7

ì

1. How is sound produced?

2. What does plucking or rubbing the strings of a violin do?

3. Sound travels fastest through which type of matter? Why?

4. In this book you have read about sound. Write to explain how your ears help you hear sound. Include details from the book.

5. Compare and Contrast Sound vibrations can be fast or slow. How is the pitch of a slow vibration different from the pitch of a faster vibration?

What did you learn?Vocabularycompression wavepitchvibration

Picture CreditsEvery 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.

Photo locators denoted as follows: Top (T), Center (C), Bottom (B), Left (L), Right (R), Background (Bkgd).

13 (Bkgd, BR) Getty Images.

Scott Foresman/Dorling Kindersley would also like to thank: 3 Kim Taylor/DK Images; 15 Denoyer-Geppert International/DK Images; 7 (TL) Stephen Oliver/DK Images.

Unless otherwise acknowledged, all photographs are the copyright © of Dorling Kindersley, a division of Pearson.

ISBN: 0-328-13848-7

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 permission(s), write toPermissions 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

13848_01-04_CVR_FSD.indd Cover213848_01-04_CVR_FSD.indd Cover2 5/11/05 4:30:21 PM5/11/05 4:30:21 PM

by Wendy Weiss

13848_05-20_FSD.indd 113848_05-20_FSD.indd 1 5/11/05 4:30:58 PM5/11/05 4:30:58 PM

What Sound Is

RING

SIZZLE SIZZLE

SIZZ

LE

RING

RING

Sounds are all around us. Think about how many sounds you hear each morning. What wakes you up in the morning? Does an alarm clock ring? What do you eat for breakfast? Your parents may cook eggs. The eggs probably sizzle in the frying pan. These are sounds you may hear in the morning.

2


Some sounds may bother you. They may be so loud that they hurt your ears. Fire truck and ambulance sirens may make you cover your ears. Other sounds may bother you when you are trying to do something else.

Luckily, many sounds are nice to hear. Do you like to listen to music? There are many different types of music. Most people have a favorite type of music they like to listen to. There are sounds in nature too. Maybe you like to listen to chirping birds or a rushing river.

3

What sound does an ambulance make?

CHIRP CHIRP CHIRP


4

All the different sounds in the world are created in the same way. Sounds are made when matter moves back and forth really fast. A vibration is the back-and-forth movement of matter. When something vibrates, a sound is created.

Sounds can be loud or soft. Loudness describes how loud or soft sound is. Big vibrations make loud sounds. Small vibrations make soft sounds. Sounds can also be high or low. Pitch tells you how high or low sound is. Slow vibrations have a low pitch. Faster vibrations have a higher pitch.

The vibrations of the tuning fork are causing the water to splash.

Vibrating cymbal

Tuning fork


5

You can learn something about vibrations when you listen to the loudness and pitch of sounds around you.

When a book falls off a desk and hits the fl oor, it makes a loud, low thud. The sound is loud. The pitch is low. Does that mean the vibrations are big or small? Fast or slow? The book’s big vibrations are slow.

Now think about tapping a water glass with a spoon. What type of sound would you hear? Loud or soft? High or low?

TINGTING


How Sound Is MadeLet’s explore how sound is made. When a book

is dropped and a glass is tapped, two different sounds are made in two different ways. Animals are also able to make sounds in a number of ways.

An elephant makes a loud, trumpeting sound when it is upset. Just like people, elephants force air past their vocal cords in order to make a sound. Some insects, such as the grasshopper, make chirping sounds by rubbing their wings.

An elephant uses its trunk and throat to make a loud, trumpeting sound. A grasshopper uses

its wings to make a chirping sound.

WingTrunk

6


Musical instruments make sounds in different ways too. Hitting two objects together can create musical sounds. Wooden blocks and sticks are great for making music. Think about the pretty ringing sound a music triangle makes when you hit it with a metal rod.

Can you describe the sound that two wooden sticks make when you hit them together?

What sound does a triangle make if you hit it with a metal rod?

7


A violin is a stringed musical instrument. The strings make musical sounds when someone pulls at, or plucks, them. Rubbing a bow across the strings also creates sound. When you pull at or rub the strings, they begin to move. Their vibrations make sound. When you pluck a violin string, you can make a short sound. If you rub a bow across that string, you can make a sound that lasts as long as you want.

This girl is rubbing the strings of a violin with a bow.

8


You can also use air to make sounds. In order to talk, you need to let out air. The air passes over your vocal cords. They make the air vibrate. The tighter your vocal cords are, the higher the pitch of your voice.

Think about blowing into an empty glass bottle. Does this make a sound? If you do it right, yes! Can you whistle? If you can, it is because you are able to push air out through your lips. This causes the air to vibrate.

Blow into bottles fi lled with liquid. Does the amount of liquid change the sound each bottle makes?

9


How Sound MovesYou now know that sound is created by

vibrations. You have also learned how different sounds are made by using air, by hitting objects, or by pulling and rubbing strings. But how does sound get from the place where it is made to your ears?

10


Sound can travel through all three forms of matter—solids, liquids, and gases. Sound comes from vibrations. These vibrations make particles of matter squeeze together and move apart very, very quickly. This type of vibration makes a wave pattern that scientists call a compression wave. All sound waves are compression waves.

This sound wave is traveling through the air. The area of squeezed particles moves along the wave. It moves in the direction the sound is traveling.

Area of squeezed air particles

Direction of sound wave

11


We usually cannot see sound traveling through matter. Scientists have special tools to measure the size and speed of sound waves. Scientists know that sound travels fastest through solids. This is because the particles are closest together in this form of matter. Since the particles are so close together, they bump into each other more easily. Then the wave is able to move quickly through the particles. Sound moves the slowest through gases. Gas particles are spread far apart and cannot transfer vibrations as easily or quickly.

Sound travels through steel

at 5,200 metersper second.

Sound travels through water at 1,530 meters

per second.

Sound travels through air

at 340 metersper second.

Ball made of steel

Bowl of water Balloon fi lled with air

12


Some sound waves have special names. Echoes are sound waves that have been traveling forward but suddenly hit a large, solid object. Then the waves bounce back the way they came. Echoes are fun to hear, such as when you shout your name while standing in an empty gym.

Echoes are also useful. Scientists use a type of echo called sonar to fi gure out how deep the ocean is. They do this by sending a sound wave to the bottom and waiting for it to bounce back. The depth is based on how long this takes.

Ships use sonar to measure ocean depths.

13


How We Hear Sounds

What happens when sounds reach your ears? Ears are shaped to catch the sounds from all around us. Each part of the ear has a special job.

Think about the shape of your ear. Does it seem silly to you? It’s actually very useful. The cuplike shape collects sounds that travel near the ear. The shape also helps move these sounds inside the ear.

As sound waves travel into the ear, the fi rst thing they reach is the eardrum. The eardrum is a thin, skinlike layer that stretches across the inside of the ear. When sound waves hit the eardrum, it begins to vibrate. Then these vibrations move farther into the ear.

14

RINGRING


Next, the vibrations reach three tiny bones that touch the eardrum. These bones vibrate when the eardrum does. They pass the sound along to the inner ear.

The inner ear has a part that is shaped like a shell and is lined with tiny hairs. This part is full of liquid. The vibrations from the tiny bones make the hairs in the liquid vibrate. These hairs are attached to nerves that carry vibration signals to the brain. The brain then identifi es the sound.

15

Outer ear

Eardrum Ear bones Inner ear

Parts of the ear


compression wave a sound wave created by the in-and-out movement of particles of matter

pitch the speed of vibrations that create a low or high sound

vibration very quick back-and-forth movement of matter

Glossary

16


1. How is sound produced?

2. What does plucking or rubbing the strings of a violin do?

3. Sound travels fastest through which type of matter? Why?

4. In this book you have read about sound. Write to explain how your ears help you hear sound. Include details from the book.

5. Compare and Contrast Sound vibrations can be fast or slow. How is the pitch of a slow vibration different from the pitch of a faster vibration?

What did you learn?Vocabularycompression wavepitchvibration

Picture CreditsEvery 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.

Photo locators denoted as follows: Top (T), Center (C), Bottom (B), Left (L), Right (R), Background (Bkgd).

13 (Bkgd, BR) Getty Images.

Scott Foresman/Dorling Kindersley would also like to thank: 3 Kim Taylor/DK Images; 15 Denoyer-Geppert International/DK Images; 7 (TL) Stephen Oliver/DK Images.

Unless otherwise acknowledged, all photographs are the copyright © of Dorling Kindersley, a division of Pearson.

ISBN: 0-328-13848-7

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 permission(s), write toPermissions 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

13848_01-04_CVR_FSD.indd Cover213848_01-04_CVR_FSD.indd Cover2 5/11/05 4:30:21 PM5/11/05 4:30:21 PM

previous: next:

Scott Foresman Science, Grade 3, Leveled Readeralarm clock ring? What do you eat for breakfast? Your...

Documents

Transcript of Scott Foresman Science, Grade 3, Leveled Readeralarm clock ring? What do you eat for breakfast? Your...