K 1 2 3 4 5GR W • Benchmark 48 • Lexile 870 Real-World Problem Solving Math and ScienceMath and Science

M

ATH E M ATICS

ISBN: 978-0-02-101108-7MHID: 0-02-101108-7

Math and Social Studies Math and Social Studies Math and ScienceMath and Science

Taking to the Skies

Water Works

Inside a Science Museum

How Big is the Solar System?

The Shifting Nature of Weather

Matter All Around

Nature’s Delicate Balance

Into Uncharted Territory

Early American Settlements

Our Nation’s Fifty States

Life in Colonial America

Flags: Shaping History

Exploring the World by Sea

A Growing Nation

City Planning

About the Cover

Copyright © McGraw-Hill Education. All rights reserved.Except as permitted under the United States Copyright Act, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without prior permission of the publisher.

Send all inquiries to:McGraw-Hill Education8787 Orion PlaceColumbus, OH 43240-4027

ISBN: 978-0-02-101108-7MHID: 0-02-101108-7

Printed in the United States of America.

7 8 9 10 DOC 20 19 18 17 16 15 14

Cover Credit: Brad Perks Lightscapes/Alamy

We often see fog in the morning and then it seems to disappear. What do you think happens to it?

1. Look at page 5. Describe how to find the fraction of Earth’s water that is not made up of the ocean. [Section 2]

2. Look at page 15. One city receives rain 17 more days than Tucson. Write a fraction to represent this part of a year. Use a simplified fraction. [Section 3]

3. Look at page 16. Find the average monthly rainfall in New York City from February to May. (Hint: find the total amount of precipitation and then divide by four.) [Section 3]

4. Look at page 16. Explain why Luis chose to make a bar graph instead of a circle graph to represent the data in the table. [Section 3]

5. Look at page 16. What information can you get from the bar graph? [Section 3]

Real-World Problem Solving

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What is a Cycle?. . . . . . . . . . . . . . . . .2

The Water Cycle . . . . . . . . . . . . . . . . .4

Precipitation . . . . . . . . . . . . . . . . . . . 10

Floods and Droughts . . . . . . . . . . . . 18

Returning to Earth . . . . . . . . . . . . . 20

Glossary . . . . . . . . . . . . . . . . . . . . . . 24

2

What is a Cycle?Many different kinds of cycles exist

on Earth. A cycle is a series of events that happens over and over in the same way each time. The four seasons of the year and the rising and setting of the Sun each day are both cycles. Can you think of other examples of cycles?

The water cycle is one of the most important cycles that occur on our planet. The water cycle brings fresh water to the earth and replenishes supplies of water in oceans, lakes, rivers, and under the ground. Without sources of fresh water, animals and plants will eventually die; therefore, all living things need water to survive.

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The Water CycleSalt water makes up most of Earth’s water

supply. This water is too salty for drinking, washing, and most other everyday uses. The water cycle replenishes Earth’s supply of fresh water. The illustration below shows each step of the water cycle.

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1. Water evaporates from oceans and other water sources.

2. Water vapor in the air cools and forms clouds.3. Water from clouds falls to Earth as rain, ice, or snow.4. Water runs along the ground and returns to oceans,

rivers, and lakes. Some water soaks into the ground.

Oceans make up about 96.5% of all the water on Earth. That means that only 3.5% of Earth’s water comes from lakes, rivers, streams, groundwater, and other sources.

Oceans

Other

Earth’s Water

6

TALK ABOUT IT

You probably think of water as a clear liquid, but water on our planet moves and changes form constantly. The majority of water in the oceans, rivers, lakes, and under the ground is in liquid form. However, a huge amount of the Earth’s supply of water stays frozen in the polar ice caps.

Water vapor in the air also retains trillions of gallons of additional water. Water vapor forms when heat from the Sun causes tiny droplets of water to change to a gas through a process called evaporation. All of this water vapor rises into the air and forms clouds. In addition to the Sun heating droplets of water, trees and other plants also give off water vapor through their leaves.

Imagine you are conducting a science experiment about evaporation. Your measurements show that 1.8 ounces of water evaporates from a container of water each day. Estimate the total amount that will evaporate after 30 days.

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Evaporation happens when water from oceans, lakes, rivers, plants, and the soil rises into the air as a gas called water vapor.

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TALK ABOUT IT

Water vapor cools as it rises into the air. The cooled water vapor then returns to liquid form. This entire process is called condensation. Clouds are formed when water vapor condenses onto dust particles in the air.

Clouds come in a variety of shapes, colors, and sizes. Scientists have a name for every kind of cloud. The way clouds form depends on the weather, air temperature, and wind conditions. Clouds that form close to the ground are made of tiny droplets of liquid water, whereas clouds that form higher in the sky are made of ice crystals.

Cirrostratus

Stratocumulus

Nimbostratus

Fog is actually a very low-lying cloud! The lowest clouds are known as stratus. When these clouds come in contact with the ground, we see fog.

Which type(s) of clouds are between 2 kilometers and 5 kilometers above the ground?

Cirrus

Cirrocumulus

Cumulonimbus

Altocumulus

Altostratus

Cumulus

Stratus

Hig

h cl

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Mid

dle

clo

uds

Low

clo

uds

13 km

5 km

2 km

0 km

TALK ABOUT IT

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PrecipitationClouds get heavier as water droplets

continue to condense. Eventually, the clouds become saturated, so the water then falls back to Earth in the form of precipitation.

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Suppose your class measured rainfall on your playground. After 3 days, your cup had 5.6 inches of rain. Estimate how much rain fell per day.

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When water falls to Earth, it can be in various states, such as rain, sleet, snow, freezing rain, or hail. Rain is liquid precipitation. If rain freezes solid as it falls through the cold air, it becomes freezing rain, snow, or another form of ice depending on the weather. Sleet is partially-frozen rain. Snow falls as flakes of fine, frozen ice crystals, while hail is a hard pellet of ice.

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Hail

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Snow

The heaviest piece of hail ever recorded in the United States weighed 1.7 pounds!

PACIFICOCE A N

200 miles0

200 kilometers

100

1000

PACIFICOCEAN

400 miles0

400 kilometers

200

2000

ARCTIC OCEAN

Ber

ing

Str

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BeringSea

Gulf of Alaska

Yearly Precipitation Across the United States

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Do you receive a lot of rain or snow throughout the year where you live? Some parts of the country get a lot of precipitation, while other places remain dry. Landforms, wind patterns, and oceans can significantly affect the amount of precipitation an area gets. The map below shows how much precipitation falls in different areas of country.

Gulf of Mexico

AT L A N T ICOCE A N

300 miles0

300 kilometers

150

1500

More than 60 inchesVery wet40–60 inchesWet20–39 inchesDryLess than 20 inchesVery dry

Average yearly precipitation

15

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Tucson, Arizona, gets much less rain than Columbus, Ohio. One year, it rained a total of 132 days in Columbus. It rained only 1 __ 4 as many days in Tucson. How many days did it rain in Tucson that year?

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Luis decided to compare the amount of precipitation that fell each month in different cities. He chose four cities in different regions of the United States. Luis researched the amount of rainfall or snowfall over four months and recorded the data he found in a table and on a graph. He presented his findings as part of a science project.

City Name

Austin, Texas

Chicago, Illinois

New York City, New York

San Diego, California

February

2.17

1.36

3.28

1.64

March

1.87

2.69

4.08

1.77

April

2.56

3.64

4.20

0.79

May

4.78

3.32

4.42

0.19

Precipitation Amounts (inches)

12345

Precipitation Amounts

0Chicago,Illinois

FebruaryMarchAprilMay

Austin,Texas

San Diego,California

New York City,New York

City

Prec

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What is an advantage of showing data in a table? What is an advantage of showing data in a graph?

TALK ABOUT IT

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Flood and DroughtsFlooding is a major problem in some

parts of the United States. Floods occur when rain falls so quickly or for such a long period of time that it cannot be absorbed by the earth. Rivers or lakes may overflow. Land, streets, cars, and even houses may be submerged in water.

Floods can cause big problems.

The town of Greenville had a flood after it rained every day for three weeks. In those 21 days the total amount of rainfall was around 40 inches. Estimate to find out about how much rain fell on average each day.

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A drought occurs when an area experiences dry conditions for a long period of time. Areas experiencing a drought may go weeks, months, or even years without precipitation.

During a drought, the soil becomes dry and cracked, and lakes and rivers dry up. Droughts can have grueling consequences for living things. People, animals, and plants cannot find the water they need.

Droughts happen when there is not enough rain for a long time.

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Returning to EarthAs you have read, when it rains or

snows, the water returns to Earth and replenishes our water supply. Some water goes directly back into the oceans. When rain falls over land or when frozen snow and ice finally melt, the water soaks into the ground or flows into rivers and lakes.

Scientists have ways of measuring and estimating the total rainfall over large areas of land. The numbers they are working with are often so large that scientists use scientific notation when recording the amounts of precipitation in a given area.

A scientist recorded the total rainfall over a large forest as 9 × 106 gallons. This means 9 × 10,000,000. What is this amount written in standard form?

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Rainwater that sinks deep into the ground is called groundwater.

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The precipitation that is absorbed into the ground seeps through cracks in rocks and soil. While trees and other plants use some of this water, most of it continues to seep farther into the ground. Eventually, it reaches the groundwater supply that is deep below the soil. Can you find the groundwater in the diagram?

Some groundwater is pumped out through wells that people use to get the water they need for bathing, cooking, drinking, and washing, while some groundwater ends up back in oceans, rivers, and lakes.

The amount of groundwater in the United States is 20 to 30 times greater than the amount of water found in lakes, rivers, and streams combined.

TALK ABOUT IT

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Our sources of water are renewed over and over again through the water cycle. Water evaporates, makes clouds, rains back down to Earth, and then the cycle begins again. The cycle never stops.

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The United States is one of the largest water-well markets in the world with about 16 million wells. This amount is 4 times as large as the amount of water wells in China. About how many water wells does China have?

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condensationWater changing from a gas to a liquid. (page 8)

evaporatesWater changing from a liquid to a gas state. (page 5)

groundwaterStored amounts of water beneath the ground. (page 22)

precipitationAny form of water particle falling to Earth’s surface. (page 10)

water cycleThe continuous movement of water between Earth’s surface and the air, changing from liquid to gas, and back to liquid. (page 2)

Glossary

About the Cover

Copyright © McGraw-Hill Education. All rights reserved.Except as permitted under the United States Copyright Act, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without prior permission of the publisher.

Send all inquiries to:McGraw-Hill Education8787 Orion PlaceColumbus, OH 43240-4027

ISBN: 978-0-02-101108-7MHID: 0-02-101108-7

Printed in the United States of America.

7 8 9 10 DOC 20 19 18 17 16 15 14

Cover Credit: Brad Perks Lightscapes/Alamy

We often see fog in the morning and then it seems to disappear. What do you think happens to it?

1. Look at page 5. Describe how to find the fraction of Earth’s water that is not made up of the ocean. [Section 2]

2. Look at page 15. One city receives rain 17 more days than Tucson. Write a fraction to represent this part of a year. Use a simplified fraction. [Section 3]

3. Look at page 16. Find the average monthly rainfall in New York City from February to May. (Hint: find the total amount of precipitation and then divide by four.) [Section 3]

4. Look at page 16. Explain why Luis chose to make a bar graph instead of a circle graph to represent the data in the table. [Section 3]

5. Look at page 16. What information can you get from the bar graph? [Section 3]

Real-World Problem Solving

K 1 2 3 4 5GR W • Benchmark 48 • Lexile 870 Real-World Problem Solving Math and ScienceMath and Science

M

ATH E M ATICS

ISBN: 978-0-02-101108-7MHID: 0-02-101108-7

Math and Social Studies Math and Social Studies Math and ScienceMath and Science

Taking to the Skies

Water Works

Inside a Science Museum

How Big is the Solar System?

The Shifting Nature of Weather

Matter All Around

Nature’s Delicate Balance

Into Uncharted Territory

Early American Settlements

Our Nation’s Fifty States

Life in Colonial America

Flags: Shaping History

Exploring the World by Sea

A Growing Nation

City Planning