California Leveled Science Readers (Grade 5) Content leveled readers teach science concepts, vocabulary, and reading skills – at each student’s reading level – and allow students to read and explore the wonders of nonfiction. Leveled science readers deliver science content to help address the individual needs of all students. They reinforce reading skills and strategies while promoting science understanding. Each grade 5 science reader is a richly illustrated, selfcontained little book with 10 to 14 double pages. BELOW 5.1 Building Blocks of Matter (Physical Sciences) 5.2 Changes in Matter (Physical Sciences) 5.3 Basic Structures of Organisms (Life Sciences) 5.4 MISSING 5.5 Water on Earth (Earth Sciences) 5.6 Weather (Earth Sciences) 5.7 The Solar System (Earth Sciences) ON 5.1 Understanding Matter (Physical Sciences) 5.2 How Matter Changes (Physical Sciences) 5.3 The Building Blocks of Organisms (Life Sciences) 5.4 Systems of the Human Body (Life Sciences) 5.5 Earths Hydrosphere (Earth Sciences) 5.6 How Weather Works (Earth Sciences) 5.7 Earths Solar System (Earth Sciences) ADVANCED 5.1 Atoms (Physical Sciences) 5.2 Acids and Bases at Work (Physical Sciences) 5.3 MISSING 5.4 MISSING 5.5 MISSING 5.6 Hurricanes (Earth Sciences) 5.7 The Red Planet (Earth Sciences)
Trang 1Genre Comprehension Skill Text Features Science Content
Nonfi ction Main Idea and Details • Captions
• Labels
• Diagrams
• Glossary
Water on Earth
Scott Foresman Science 5.5
Standards Preview
Standard Set 3 Earth Sciences
3 Water on Earth moves between the
oceans and land through the processes
of evaporation and condensation As a
basis for understanding this concept:
3.a Students know most of Earth’s
water is present as salt water in the
oceans, which cover most of Earth’s
surface.
3.b Students know when liquid water
evaporates, it turns into water vapor
in the air and can reappear as a liquid
when cooled or as a solid if cooled
below the freezing point of water.
3.c Students know water vapor in
the air moves from one place to another and can form fog or clouds, which are tiny droplets of water or ice, and can fall to Earth as rain, hail, sleet, or snow.
3.d Students know that the amount
of fresh water located in rivers, lakes, underground sources, and glaciers is limited and that its availability can be extended by recycling and decreasing the use of water.
3.e Students know the origin of water
used by their local communities.
ISBN 0-328-23464-8 ì<(sk$m)=cdegeg< +^-Ä-U-Ä-U
by Kristin Cashore
Earth Sciences
Trang 2aquifer
condensation
evaporation
precipitation
reservoir
salinity
sea level
sleet
water cycle
water table
watershed
Picture Credits
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 copyright © of Dorling Kindersley, a division of Pearson.
ISBN: 0-328-23464-8
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 to
Permissions Department, Scott Foresman, 1900 East Lake Avenue, Glenview, Illinois 60025.
1 2 3 4 5 6 7 8 9 10 V010 13 12 11 10 09 08 07 06
by Kristin Cashore
Trang 3How can the oceans
be described?
The Hydrosphere
Bodies of water, such as rivers, lakes, and oceans, are
very important to us We can travel and catch food on
bodies of water We can enjoy them for their natural beauty
What bodies of water are near you?
The hydrosphere is made up of all of the water on
Earth It covers three-fourths of Earth’s surface
Oceans, rivers, and lakes are all part of
the hydrosphere Only 3/100 of the
hydrosphere is not in the ocean
The Pacifi c Ocean is the
biggest ocean Next comes the
Atlantic Ocean, the Indian
Ocean, the Southern
Ocean, and the Arctic
Ocean The oceans
are all connected to
each other
3
The Pacifi c Ocean is the biggest ocean It is the deepest ocean too Its average depth is about 4,000 meters It is more than 11,000 meters deep at its deepest place
Every ocean is different Each ocean’s water is at different average depths Some have more storms than others do They have different temperatures and different
amounts of salt Even sea level, the level of the ocean’s
surface, is slightly different from ocean to ocean
Trang 4Earth’s Oceans
Ocean water is salty Rivers make the oceans salty Rain
falls on the oceans and the land Rain can dissolve salts
and other minerals when it falls on land Rivers then carry
these salts and minerals into the oceans Water evaporates
from the surface of the ocean, but the salts are left behind
in the water
Salinity is a measure of the amount of salt in water
Some parts of the ocean have less salt than others Places
where fresh water from rivers fl ows into the ocean have low
salinity In warm, dry places ocean water evaporates fast
This leaves salt behind, so the ocean has a higher salinity
Cold water with high salinity weighs more than the
same amount of water that is warmer It also weighs more
than the same amount of water with lower salinity The
blue-colored water below is warmer and has lower salinity
than the clear water The blue water fl oats on the clear
water because of this
The blue water is at room
temperature and has one-half of
a spoonful of salt The red water
is warm and has no salt The
blue layer fl oats on top of the
clear water, which is cold and has
more salt.
5
Ocean Temperatures
Not all ocean water is at the same temperature Ocean water near the equator is about 30°C Ocean water near the poles can be as cold as a –2°C
Currents in the ocean move water back and forth Some currents carry warm water toward the poles The Gulf Stream is one current that does this It brings warm water from the Carribean Sea to the North Atlantic Ocean Other currents carry cold water toward the equator The California Current runs along the west coast of the United States It brings cold water toward the south
Ocean Resources
The oceans are very important to our Earth People get food and other materials from the ocean A lot of the salt
we use for food is from the ocean People who process salt let ocean water fl ow into shallow ponds When the water evaporates, salt is left behind
When ocean water in these ponds evaporates, salt is left behind.
Trang 5Where is fresh water
found?
Drinking water is also called fresh water Fresh water
has much less salt than seawater Almost all fresh water
begins as rain or snow Some sinks into the ground Some
collects in rivers and lakes Some freezes into ice sheets and
glaciers
Some places have much more fresh water than others
But fresh water around the world is limited People should
try to use less water They should recycle water if they can
Groundwater
Groundwater is rain or melted snow that sinks into the
ground Groundwater fi lls spaces between pieces of rock and
soil It sinks until it reaches a layer of rock or clay it cannot
move through Water can fl ow over these layers
The layer of rock and
soil that groundwater fl ows
through is called an aquifer
The top level of groundwater
in an aquifer is the water
table The level of the water
table depends on how much it
rains or snows People can use up
the water in an aquifer if they are
not careful
7
Rivers
Rivers, streams, and lakes are all surface waters Creeks run downhill, full of rainwater and melted snow The creeks join to form streams and rivers Groundwater also seeps
into rivers Most rivers fl ow into the ocean A watershed is
the area from which water drains into a river
A watershed can have a big effect on a river If chemicals are dropped in a watershed, they can be carried
by water to rivers This can change river ecosystems
Lakes
Lakes form when water collects in a low spot Lakes may be surrounded by higher land or blocked by a dam A
reservoir is usually an artifi cial lake that forms behind
a dam
A lake, pond, stream, or swamp forms where the water table meets the surface.
Trang 6Ice
About seven-tenths of Earth’s fresh water is frozen!
This makes it hard for people to use In Greenland and
Antarctica, big ice sheets cover most of the land The sheets
can be several kilometers thick These places are where
much of Earth’s ice is found
Glaciers
Smaller sheets of ice are called glaciers Valley glaciers
sit in the valleys of high mountains They move slowly
downhill As they move, they cut into the rock and move it
This changes the shape of the valley
Glaciers and ice sheets form when the amount of
snowfall is greater than the amount of snow that melts
Over time, the snow underneath is pressed into ice by the
snow on top Large pieces of glaciers and ice sheets can
break off into the ocean These pieces are called icebergs
9
Getting Water to Homes
In the United States, some towns get water from groundwater or surface water But sometimes this water has harmful bacteria or is polluted with chemicals Water must
fi rst be treated before it is safe to use
Water is treated at a treatment plant First, water is pumped from a river or lake through screens to a tank
Then, chemicals are added to the water These chemicals make small particles stick together The larger particles that are formed then sink to the bottom of the tank Next, the water passes through fi lters made of sand and gravel
The fi lters take out smaller particles Finally, even more chemicals are added to the water Chemicals such as chlorine kill harmful bacteria After the water is treated, it
is stored in a water tower
Now you know that a lot must happen before water gets to your home This is why it is very important not to waste water
This iceberg is in Greenland Only 1/10 of the iceberg fl oats above the water You cannot see the 9/10 that is underwater.
Trang 7<PHOTO: pick up image of
dam from page 168 of SE.>
10
What are some
California water
sources?
Too Much or Not Enough?
Some parts of California get a lot of rain Other parts
are very dry The northern coastal region of California gets
about 250 centimeters of rain every year But the deserts of
southeastern California get only about 10 centimeters of
rain every year Because of this, the supply of fresh water in
southern California is limited However, southern California
uses about two-thirds of the fresh water used in the state!
A lot of California’s water comes from winter snow
When the snow melts, its fresh water runs from the
mountains into streams and lakes This water is collected
and sent all over the state
11
Transporting Water Throughout California
Aqueducts help to carry water throughout California
An aqueduct is a system of pipes that carries water from one place to another Aqueducts carry water from rivers and lakes to where it is needed
There are many aqueducts in California The California Aqueduct brings water from the mouth of the Sacramento River to communities more than 400 kilometers away
The Los Angeles Aqueduct carries water from a number of sources to Los Angeles The Colorado River Aqueduct carries water from the Arizona border to Riverside County That is
a distance of almost 390 kilometers! From there it travels south to San Diego
Melted snow runs out of the Sierra Nevada It provides drinking water to many Californians.
Trang 8This farm uses reclaimed water for watering crops to help save water.
Local Water Sources
Did you know that everyone lives in a watershed? The
amount of water in the watershed determines how much
water an area has to use Water from rain and snow falls in
streams, rivers, and lakes Water also sinks into the soil and
becomes groundwater Both surface water and groundwater
are available for people to use
The way land in a watershed is used affects how clean
the water is Chemicals that are use in cities and on farms
can be carried in water that runs off streets and farms Soil
that is being disturbed by construction can also get into
water The land must be used wisely to help keep water safe
This is why there are laws to keep water safe
Conservation is using a resource such as water wisely
so that it lasts longer Taking shorter showers and fi xing
leaky faucets and toilets are some of the ways people can
conserve water
13
Reclamation
Water can be recycled and used again This is called reclamation In reclamation, wastewater is carried to a treatment plant After being treated, the water can be used for things other than drinking For example, it can be used
to water lawns or crops
Finding Out About Local Water Sources
Some places get their fresh water from nearby water sources Other places use aqueducts to get water from far away
The amount of water in these lakes and rivers depends
on how much rain and snow falls there It also depends on how people use the water
Where does your water come from? Try contacting your local water company or going to the library-media center to fi nd out
Trang 9Condensation
What is the
water cycle?
Water in the Air
Did you know that the air around you has water in it?
This water is not in a liquid form, like the water in a river It
is also not in a solid form, like the ice in a glacier The water
in the air is an invisible gas called water vapor
Air always has some water vapor in it Even desert air
contains water vapor Water vapor was liquid water at some
time in the past It may have been part of a river or an
ocean, or may have even been inside a plant!
The particles of water vapor are like the particles of
other gases They are always moving
Evaporation
Precipitation
15
The Water Cycle
Water moves from the oceans to the land and back
again through a process called the water cycle The
water cycle is the repeated movement of water through the environment in different forms It is also called the hydrologic cycle The water cycle has many steps
Evaporation is the changing of liquid water to water
vapor Liquid water changes into water vapor when it is heated by the Sun Condensation happens when air cools
water vapor Condensation is the changing of water
vapor back into a liquid, such as water droplets in clouds
or fog The droplets are so small that they hang in the air
In precipitation, the air cools the water droplets even
more The water droplets grow big and heavy, and fall as rain, hail, sleet, or snow Water can go many different ways through the water cycle
Trang 10Water runs off the land and evaporates from plants.
Groundwater slowly moves through aquifers into rivers, lakes, and the ocean.
16
Many Paths of the Water Cycle
The water cycle is not as simple as it seems Water is not
always in the nonliving part of the environment Living
things use water During photosynthesis, plants break down
water as they make sugar Living things also release water
They do this during respiration
Because salt is left behind when water evaporates, the oceans remain salty.
As water vapor rises,
it may form a cloud.
17
Energy in the Water Cycle
The energy of the Sun is very important to the water cycle Sunlight causes melting and evaporation It also causes sublimation, or the changing of ice directly to water vapor The energy to raise water vapor to the clouds comes from the Sun The energy to move water vapor with winds also comes from the Sun
When water vapor condenses into liquid water, it releases energy This energy heats nearby air or water
When liquid water evaporates, it takes in heat energy
This cools nearby air and water
This heating and cooling can affect weather patterns
Trang 11How do clouds form?
Temperature and Pressure
Clouds come in many shapes and sizes They form when
water vapor condenses This forms water droplets or ice
crystals The condensation of water vapor to form clouds is
an important part of the water cycle
The temperature of the air is part of why a cloud is
made of water droplets or ice crystals It is much colder in
the clouds than it is on the ground Even on hot days, many
clouds are made of ice crystals
Air pressure also affects the way clouds form Clouds
often form when air rises into areas of lower air pressure As
air rises, the pressure goes down With less pressure, the air
expands and cools If the air cools enough, water vapor will
form droplets or ice crystals
Cirrus clouds are high-altitude clouds
that are thin, wispy, and white.
19
Vertical clouds are sometimes called thunderheads because they often cause thunderstorms.
Precipitation
Most rain in the United States starts as snow This is because the temperature of the air up high is often below 0°C Clouds made of ice crystals form The crystals grow bigger until they fall as snowfl akes If the temperature of the air between the cloud and the ground is less than 0°C, the ice crystals fall to the ground as snow
Falling ice crystals may change as they pass through different layers of air Ice crystals will melt if they go through air that is warmer than 0°C Then they will fall as rain If the air near the ground is very cold, the rain may freeze before
it hits the ground These frozen raindrops are sleet Freezing
rain forms when rain freezes right as it hits the ground
Hail Formation
Hail forms when strong winds blow upward into a cloud The winds blow raindrops up into the freezing air at the top of the cloud The raindrops freeze into pieces of ice
The winds blow the ice back up into the cloud many times
More layers of water freeze onto the ice Hailstones fall when pieces of ice grow too heavy for the winds to lift