Scott Foresman Science 3.6

Genre Comprehension Skill Text Features Science Content

Nonfi ction Make Inferences Captions

Map

Labels

Glossary

Weather

ISBN 0-328-13823-1

Illustration: 5, 6 Big Sesh Studios 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)Title Page: DK Images 2 John Lund/Corbis 4 Leonard Lessin/Peter Arnold, Inc. 6 DK Images 8 Corbis 9 Tom Uhlman/Visuals Unlimited 10 Tom Bean 11 Julie Eggers/Bruce Coleman Inc. 13 (T) Getty Images, (B) Allan Davey/Masterfile Corporation 14 Boden/Ledingham/Masterfile Corporation

ISBN: 0-328-13823-1

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

Vocabularyatmosphere

blizzard

hurricane

tornado

weather

What did you learn?1. What are some qualities that weather has?

2. Name three weather tools that help to measure weather. Tell what each tool does.

3. What do high air pressure and low air pressure tell us about the weather?

4. In this book you have read about the pollution that happens in cities. Write to explain how pollution forms. Use examples from the book.

5. Make Inferences Why do you think the coast of the state of Washington gets wet weather in the winter, while the Cascade Mountains in the middle of the state get snow?

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Weatherby Timothy Sandow

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What makes up weather?Parts of Weather

Weather is what the air is like outside. The air

temperature is part of the weather. So is the water in

the air. The wind speed and kinds of clouds are part of

the weather too.

Most clouds are made of water droplets. Clouds

hang in the air. When a cloud cant hold any more

water, it rains. Puffy, white clouds usually mean good

weather. Dark clouds often bring rain.

2

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Measuring Weather

You might say that the weather is hot today. But

your friend might disagree. To your friend, the weather

might not feel hot. So scientists use tools to measure

the weather. That way, we know exactly what the

weather is like!

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4

Earth has a blanket of

air around it. That blanket

is called the atmosphere.

It contains gases that have

no color, taste, or odor. The

atmosphere has weight. It

presses down on Earth. How

much it presses down is called

air pressure. High air pressure

is caused by the atmosphere

pressing down more. Low

air pressure is caused by

the atmosphere pressing

down less.

The atmosphere has many parts. Weather happens in the lower part. Planes often fly above the weather.

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Changes in air pressure lead to changes in the

weather. Scientists use a tool called a barometer to

measure air pressure.

High air pressure means good weather is coming

or is here. The skies are clear or will be clearing. Low

air pressure often means bad weather. The weather

is cloudy or rainy or will be cloudy or rainy. Storms

happen during low air pressure.

Barometer

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Enlarge

6

A hygrometer measures the airs

water vapor, or humidity. High

humidity causes damp, wet air. Low

humidity causes dry air.

A rain gauge shows how much rain

has fallen. An anemometer tells the

speed of the wind. Wind vanes tell the

direction of the wind.

All these tools help scientists learn

more about weather. They also help

scientists predict what the weather will

be like.Hygrometer

Anemometer

Wind vane

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Weather Map

Weather tools give scientists data, or facts. Scientists

use the data to make weather maps. The maps show

temperatures, air pressure, and storms. Look closely at

the weather map below. Do you see the key? The keys

pictures help you better understand the weather.

This weather map uses pictures to show what the weather is like. What is the weather like in Atlanta, Georgia?

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Weather satellites move around Earth and take

pictures. They send the pictures back to Earth.

Scientists study the pictures. The pictures help

scientists tell which way storms are moving. This

helps scientists talk about the weather.

Weather satellite

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Enlarge

9

Pollution Alerts

Cars, trucks, and factories can pollute the air

in cities. The pollution they make is a gas, called

exhaust. The exhaust moves into the air. The exhaust

can hang over the city. The Suns rays can turn the

exhaust into smog and ozone.

Weather scientists make pollution alerts when

theres smog or ozone in the air. The alerts warn

people to stay inside because smog or ozone can be

harmful to health.

Smog makes it hard for some people to breathe.

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How are weather patterns different?Weather Patterns

Weather changes follow patterns. The same weather

happens over and over again. Weather patterns

depend on the Sun, water, and where you live. People

near the ocean have one kind of weather. People far

from the ocean have another kind of weather.

The coast along the state of Washington has rainy

winters. The Cascade Mountains, near the middle of

the state, have snowy winters. And the eastern section

of Washington has dry, cold winters.

Eastern Washington State does not get much rain or snow.

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It rains on the coast because the air is warm and

wet. The rain turns to snow in the mountains because

the air is colder there. And the mountains block rain

and snow from going past them.

Each kind of desert has its own weather pattern. The

Sonoran Desert in Southern Arizona and California

has a hot, dry summer season. But storms come with

heavy rain. The rain is due to moist air from the Gulf

of California. Saguaro cactus take in the rain and save

it for later.

What kind of weather does this desert have?

11

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Dangerous Storms

Some storms only bring rain. Thunderstorms can

be dangerous. Lightning can strike people, trees, and

buildings, so people should find shelter.

A hurricane is a huge storm. It starts out over an

ocean. It has very strong winds. When it hits the land

it causes great damage. People usually know about

hurricanes before they happen.

A hurricane can cause heavy rain and huge waves.

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A tornado is a spinning column of air that touches

the ground. Tornadoes form below thunderstorm

clouds. They are smaller than hurricanes. But their

winds are much stronger. Tornados form quickly. When

a tornado is spotted, people must go to a safe place.

Heavy rains or big waves can cause flooding.

Flooding can make roads dangerous to travel on.

People usually know about flooding beforehand and

move to higher ground.

A tornado is very dangerous.

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A blizzard is a winter storm. Blizzards have very

cold air and a lot of snow. Strong winds blow the

snow. It is dangerous to be out in a blizzard. Blizzards

can trap people in the snow. They can also make

people too cold. It is important to stay indoors during

blizzards in order to be safe.

These students are sent home from school during a blizzard.

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The National Weather Service warns people about

storms. A storm watch means that a storm could be

happening soon. A storm warning means that a storm

is about to happen or is already happening.

Different kinds of weather happen every day. It is

difficult to figure out why certain weather happens.

But tools help scientists understand the weather!

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16

Glossary

atmosphere the blanket of air that surrounds Earth

blizzard a heavy snowstorm with strong winds

and cold temperatures

hurricane a huge storm with strong winds and

heavy rains that starts over an ocean

tornado a spinning, funnel-shaped column of

air that touches the ground

weather what the air is like outside

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Illustration: 5, 6 Big Sesh Studios 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)Title Page: DK Images 2 John Lund/Corbis 4 Leonard Lessin/Peter Arnold, Inc. 6 DK Images 8 Corbis 9 Tom Uhlman/Visuals Unlimited 10 Tom Bean 11 Julie Eggers/Bruce Coleman Inc. 13 (T) Getty Images, (B) Allan Davey/Masterfile Corporation 14 Boden/Ledingham/Masterfile Corporation

ISBN: 0-328-13823-1

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

Vocabularyatmosphere

blizzard

hurricane

tornado

weather

What did you learn?1. What are some qualities that weather has?

2. Name three weather tools that help to measure weather. Tell what each tool does.

3. What do high air pressure and low air pressure tell us about the weather?

4. In this book you have read about the pollution that happens in cities. Write to explain how pollution forms. Use examples from the book.

5. Make Inferences Why do you think the coast of the state of Washington gets wet weather in the winter, while the Cascade Mountains in the middle of the state get snow?

13823_CVR_FSD Sec1:213823_CVR_FSD Sec1:2 05/12/2005 18:29:0205/12/2005 18:29:02

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