The Sun, Water Cycle and Climate TG quark - Discovery Education ...

The Sun, Water Cycle,
and Climate
Distributed by...
From the series
Water Smart
Written and Produced by
Alan Sealls, B.S., M.S.
800.323.9084 | FAX 847.328.6706 | www.unitedlearning.com

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© 2004 Alan Sealls

Table of Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Links to Curriculum Standards . . . . . . . . . . . . .2
Summary of the Program . . . . . . . . . . . . . . . . .3
Instructional Notes . . . . . . . . . . . . . . . . . . . . . .4
Pre-Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Student Preparation . . . . . . . . . . . . . . . . . . . . . .4
Student Objectives . . . . . . . . . . . . . . . . . . . . . .5
Introducing the Program . . . . . . . . . . . . . . . . . .5
View the Program . . . . . . . . . . . . . . . . . . . . . . .6
Discussion Questions . . . . . . . . . . . . . . . . . . . .6
Description of Blackline Masters . . . . . . . . . . .7
Answer Key . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Extended Learning Activities . . . . . . . . . . . . . .15
Script of Narration . . . . . . . . . . . . . . . . . . . . . .16
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The Sun, Water Cycle, and Climate
from the series Water Smart
Grades 3-8
Viewing Time: 15 minutes
INTRODUCTION
Water Smart is a unit of study comprised of four programs.
Spectacular video examples and supporting material make the
study of water come alive to students. Every program's
teacher's guide lists water-related projects that students at even
the lowest grades can undertake, while each guide suggests
advanced study topics and projects. The series is an entire
"course" in the courses of water in our world and in our lives.
Each program stands alone in approaching the various facets of
water on Earth. These colorful, educational, and entertaining
programs highlight the crucial role water plays in life and how
kids can help to conserve and protect it.
The Water Smart series is written and produced by Alan Sealls,
an award-winning meteorologist recognized nationally in science
textbooks, CD-ROMs, and educational TV programs.
Alan Sealls holds B.S. and M.S. degrees in Meteorology. He
has worked for WGN-TV, CNN, and other TV stations around
the United States.
The Sun, Water Cycle, and Climate shows us how the sun produces
heat to drive the water cycle. It's made clear that the
water cycle continues in the absence of sunlight or heat. We
learn how the two components of climate- temperature and precipitation,
are influenced by the water cycle. By the program
conclusion, kids are able to explain how the water cycle and climate
are dependent on the sun.
1

LINKS TO CURRICULUM STANDARDS
The Sun, Water Cycle, and Climate correlates to the following
science standards:
National Science Education Standards, K-4
Science as Inquiry
CONTENT STANDARD A:
Abilities necessary to do scientific inquiry
Understanding about scientific inquiry
Physical Science
CONTENT STANDARD B:
Properties of objects and materials
Life Science
CONTENT STANDARD C:
The characteristics of organisms
Organisms and environments
Earth and Space Science
CONTENT STANDARD D:
Properties of earth materials
Objects in the sky
Changes in earth and sky
Science and Technology
CONTENT STANDARD E:
Abilities of technological design
Science in Personal and Social Perspectives
CONTENT STANDARD F:
Personal health
2

National Science Education Standards, 5-8
Science as Inquiry
CONTENT STANDARD A:
Abilities necessary to do scientific inquiry
Understandings about scientific inquiry
Physical Science
CONTENT STANDARD B:
Properties and changes of properties in matter
Motions and forces
Earth and Space Science
CONTENT STANDARD D:
Structure of the earth system
Science and Technology
CONTENT STANDARD E:
Abilities of technological design
Science in Personal and Social Perspectives
CONTENT STANDARD F:
Personal health
SUMMARY OF PROGRAM
The Sun, Water Cycle, and Climate presents the sun as the
source of energy for Earth, driving the water cycle. This program
covers the fundamental phases of the water cycle but goes
beyond precipitation, evaporation, and condensation. We recognize
how plants assist in evaporation via transpiration. We
also see how ice "evaporates" in the process of sublimation.
Runoff is presented as a link between precipitation and evaporation
as water flows into lakes and oceans. The heat capacity
of oceans and large water bodies is shown to be a climate control,
all at a level that kids comprehend. Excellent visuals and
animations illustrate unique forms of condensation in dew and
frost. Students become aware that the water cycle is far-reaching,
never-ending, and crucial to life in plants and people.
3

At the program conclusion, a true/false quiz assesses students
understanding. Teachers will be able to further illustrate components
of the water cycle using the eight experiments and
demonstrations provided. Measuring rainfall, for example,
allows practice in recording and charting data. In addition,
twelve unique Internet links will lead to further study by kids,
and additional lesson plan ideas for the classroom.
INSTRUCTIONAL NOTES
Before presenting this lesson to your students, we suggest that
you preview the program and review the guide and accompanying
Blackline Master activities in order to familiarize yourself
with their content.
As you review the materials presented in this guide, you may
find it necessary to make some changes, additions, or deletions
to meet the specific needs of your class. We encourage you to
do so; for only by tailoring this program to your class will they
obtain the maximum instructional benefits afforded by the
materials.
PRE-TEST
Pre-Test is an assessment tool intended to gauge student comprehension
of the objectives prior to viewing the program.
Explain to the students that they are not expected to get all
answers correct, but they are expected to try their best. You can
remind them that these are key concepts that they should focus
on while watching the program.
STUDENT PREPARATION
Find information on the Internet or from your local county
cooperative extension on how much rain or snow falls in your
community each year. Have students guess the number of inches.
Have students list what happens to the rain or snow after it
hits the ground. Have them describe where they've seen it go.
4

Likely answers are that the snow melts, and like rain, it flows
into drains or downhill into streams. Some kids may note that
the water also seeps into the ground.
Speculate what would happen if several years of below-average
rain or snow occur. Look for articles describing the effects of
drought. Likewisem look for current event articles of the effects
of too much precipitation.
Use Blackline Master #5 to introduce vocabulary relevant to
water on the Earth. Have students look up and define each
word. Any one of the Blackline experiments will help raise the
interest of students as you start the program.
STUDENT OBJECTIVES
Upon completion of the program and follow-up activities, students
should be able to:
• Identify the source of energy for the water cycle.
• Explain unique forms of condensation.
• Describe the role of plants in the water cycle.
• Illustrate the large heat capacity of water.
• Discuss how runoff fits into the water cycle.
• Describe the phases of water.
• Define transpiration, percolation, evaporation, and condensation.
• Discuss the role of clouds in influencing temperature.
• Outline the water cycle.
• Describe how the water cycle provides fresh water.
• Predict relative rates of evaporation for water.
INTRODUCING THE PROGRAM
Engaging the students before they view the program is key in
maximizing its impact. Start by simulating the water cycle.
Demonstrate how water in a pot will evaporate when heated.
Hold another pot or pan above the steam from the evaporating
5

water to see it condense and fall back as droplets. Draw parallels
between evaporation, condensation, precipitation, and
runoff. Ask students to describe what they think controls the
water cycle, and how the water cycle might control the climate
for a city.
It is best to identify misconceptions and misinformation about
the water cycle before the lesson. Pre-Test or discussion questions
may be used to help accomplish this.
A video quiz corresponding to Blackline Master #4 is at the
program conclusion. You may choose to pause the program for
a longer period of time between questions to allow for answers
or discussion.
VIEW THE PROGRAM
The program runs 15 minutes. Blackline Master #4, Video
Quiz, corresponds to the ten true/false questions at the end of
the program.
DISCUSSION QUESTIONS
These questions appear on Blackline Master #3, they can be
duplicated and distributed to the class. Following the program,
you may find it helpful to discuss the key concepts as a class.
You may choose to use these questions to begin a discussion
prior to viewing the program. Avoid answering questions directly;
ask the students higher-level questions allowing them to
discover the answer as a group. Feel free to add or delete questions
to suit the needs of your class. Answers are included in the
answer key of this guide.
6

DESCRIPTION OF BLACKLINE MASTERS
Blackline Master #1, Pre-Test, is an assessment tool intended
to gauge student comprehension of the objectives prior to participating
in the program.
Blackline Master #2, Post-Test, is an assessment tool to be
administered after viewing the program and completing additional
activities. The results of this assessment can be compared
to the results of Pre-Test to determine the change in student
comprehension before and after participation in this lesson.
Blackline Master #3, Discussion Questions, can be included
before viewing the program to help assess the students’ comprehension
and misgivings before beginning the lesson. Give
them to the whole class or to small groups to research and
report back to the class.
Blackline Master #4, Video Quiz, is intended to reinforce the
key concepts of the program immediately following the presentation
of the program. The quiz can be used as a tool to outline
salient points before viewing the program
Blackline Master #5, Vocabulary List, will reinforce words
used within the program and provide related vocabulary not
used in the program. From the list, you may have students look
up words to define, write essays, poetry, or short stories.
Blackline Master #6, Word Search #1, is a fun way to learn
vocabulary.
Blackline Master #7, Word Search #2, is also a fun way to
learn vocabulary.
Blackline Master #8, Crossword Puzzle #1, is another fun
way to learn vocabulary.
7

Blackline Master #9, Crossword Puzzle #2, is a fun way to
learn vocabulary.
Blackline Master #10, Crossword Puzzle #3, is also a fun way
to learn vocabulary.
Blackline Master #11, Fact Sheet Quiz, offers trivia along
with website links to further information that kids may use to
develop a game show.
Blackline Master #12, Experiment #1: Make the Water
Cycle, is a clear illustration of the components of the water
cycle.
Blackline Master #13, Experiment #2: Erosion, allows study
of what determines the rate and amount of erosion.
Blackline Master #14, Experiment #3: Fast Evaporation,
gives the opportunity to measure and determine rates of evaporation.
The amount of water used is not critical as long as it is
the same in both containers.
Blackline Master #15, Experiment #4: Terrarium, ties the
water cycle and biology together to demonstrate that they are
both linked.
Blackline Master #16, Experiment #5: Transpiration, will
amaze students as they discover how much water plants give to
the atmosphere.
Blackline Master #17, Experiment #6: Frost, teaches that
frost is not frozen water; it is vapor that turns directly to ice
crystals.
Blackline Master #18, Experiment #7: Salty Water to Fresh
Water, shows principles of evaporation and condensation
while teaching kids how to distill or desalinate saltwater.
8

Blackline Master #19, Experiment #8: Holding Heat, provides
insight into why large lakes and oceans are so important
in controlling temperatures around the world.
Blackline Master #20, Additional Internet Sites, goes further
than the sites listed in Fact Sheet Quiz. It provides a large number
of links, downloadable projects, lesson plans, and fun activities
for students. Preview all Internet sites before recommending
them to students to be certain they are appropriate for your
intended use.
ANSWER KEY
Blackline #1, Pre-Test
1. The water cycle is the cycling of water from gas to liquid or
solid, as it goes from condensation to precipitation to runoff to
evaporation. It spreads water around the Earth.
2. The sun is the source of energy for the water cycle.
3. Precipitation is any form of water that falls from clouds. It
may be rain, snow, sleet, or hail.
4. Condensation is when invisible water vapor becomes visible
as water droplets or ice crystals. This is commonly seen as
clouds, or it could be dew or frost.
5. Evaporation is when liquid water disappears into invisible
gas in the air.
6. Transpiration is when trees, bushes, and plants give off water
through their leaves.
7. Percolation is when water sinks, seeps, or soaks into the
ground.
8. Runoff is when water or melted snow flows downhill, eventually
to rivers or bodies of water.
9. Water can be in three phases, even at the same time.
10. A rain gauge measures rainfall.
Blackline Master #2, Post-Test
1. Liquid, solid, or gas. These can be also referred to as water,
ice, or vapor. Note that vapor may also refer to visible clouds
but in this program, it signifies invisible water as a gas.
9

2. Precipitation may be rain, snow, sleet, or hail.
3. Plants remove water from the ground through capillarity and
then release it into the air as water vapor through transpiration.
4. No, the water cycle never stops.
5. Frost and dew are found outside after a clear night with calm
wind, when the relative humidity reaches 100%.
6. Evaporation is when liquid water disappears into invisible
gas in the air.
7. Transpiration is when trees, bushes, and plants give off water
through their leaves.
8. Condensation forms clouds, water droplets, dew, or frost.
These are visible forms of water.
9. Percolation is when water sinks, seeps, or soaks into the
ground.
10. Clouds can block and reflect sunlight when they are thick to
keep us cool. At night, thick clouds act like a blanket to help the
Earth retain heat.
Blackline Master #3, Discussion Questions
1. The water cycle continues because heat from the sun lingers
in the air and in the water, even after sunset. Each portion of the
cycle requires another portion to happen.
2. The more direct sunlight an area gets the warmer its climate
will be. Increased temperature means a more active water cycle
due to increased evaporation. Areas with a lot of sun and bodies
of water will have warm and humid (rainy) climates. Areas
with less sun (nearer to the poles) will be colder. The water
cycle will continue but on a slower pace. These areas will have
cold climates that are drier unless they are near large bodies of
water.
3. Transpiration assists in evaporation. It removes a large
amount of water from the ground wherever there are forests,
farm fields, grass, or other plants or bushes.
4. Evaporation generally leaves pollutants and contaminants
behind. Fresh water falls in rain and snow. Snow melts and
along with rain, it flows into lakes or percolates into the ground
to restore aquifers.
5. If the water cycle stopped, eventually life would end as we
10

know it because people, plants, and animals would run out of
sources of fresh water.
6. Snow, sleet, or hail.
7. We see condensation as dew or frost on grass and windows.
We also see condensation as water droplets on the outside of a
cold soda bottle.
8. Clouds can block sunlight to give a region a cool climate. If
the clouds carry a lot of moisture, they can produce daily precipitation
to give a region a wet climate.
9. Plants help in evaporating water that falls on their leaves, and
water that transpires from their leaves. Plant roots help to
reduce runoff by slowing how fast water moves on the ground.
10. Precipitation soaks into the ground and it causes runoff.
Runoff fills rivers or bodies of water. The more water that is
spread out on the ground, the more evaporation occurs.
Transpiration pulls water out of the ground and contributes to
evaporation. As evaporation increases, the air becomes saturated
and we get condensation. Condensation produces clouds
which grow to the point of producing precipitation.
Blackline Master #4, Video Quiz
1. False. The water cycle never stops.
2. True.
3. True.
4. True.
5. False. The water cycle is everywhere.
6. True.
7. True.
8. False. There is water in the air and in the ground in a desert.
9. True.
10. True.
Blackline Master #6, Word Search #1
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Blackline Master #7, Word Search #2
Blackline Master #8, Crossword Puzzle #1
Across Down
3. porous 1. ecosystem
6. sediment 2. cycle
7. meteorologist 3. particles
11. hail 4. sun
12. frost 5. climate
8. reflect
9. solid
10. vapor
Blackline Master #9, Crossword Puzzle #2
Across Down
4. clouds 1. moisture
6. runoff 2. temperature
7. erosion 3. percolate
8. humid 5. dew
10. precipitation 9. weather
11. glacier
12. sleet
13. weather
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Blackline Master #10, Crossword Puzzle #3
Across Down
3. dissolve 1. evaporation
5. rain 2. condensation
8. snow 4. sublimation
9. transpiration 6. liquid
11. phase 7. groundwater
12. ocean 10. sea
Blackline Master #11, Fact Sheet Quiz
1. c 2. d 3. b 4. e 5. a
Blackline Master #12, Experiment #1: Make the Water Cycle
1. Heat makes the water boil.
2. The water evaporates faster as it boils.
3. Water droplets (condensation) appear on the bottom of the
pot, and then fall as precipitation.
4. This is the same process that occurs in the water cycle.
5. The ice was used to cool the air faster and resulted in
increased condensation.
Blackline Master #13, Experiment #2: Erosion
1. The water slowly soaks into the sand when sprayed gently.
2. When sprayed close up, the force of the water erodes the pile
and moves the sand grains.
3. The sand and water run off and go down the slope.
4. Erosion depends on how hard the rain falls and on how loose
the soil is that the rain lands on.
5. More water can go into the sand if it is sprayed gently, or if
grass or some other plant is grown to hold the sand together and
protect it from the direct force of falling water. You can also put
the sand in a container or build a fence or wall around it.
Blackline Master #14, Experiment #3: Fast Evaporation
1. Answers will vary.
2. Answers will vary but times should be longer than when the
water is fanned.
13

3. The fan helps the water evaporate by constantly exposing
more of the water (molecules) to air.
4. The closer the fan is to the water, the faster evaporation is.
The faster the air moves from the fan, the faster evaporation is.
5. Wind increases the rate of evaporation.
Blackline Master #15, Experiment #4: Terrarium
1. Condensation occurs on the inside of the glass.
2. The water evaporates, condenses on the glass, and then drips
into the soil.
3. The plants should live and grow.
4. This is a closed community where the water is cycled from
liquid to gas to vapor, and shared in the community.
5. We see evaporation from the cap, transpiration from the
plant, condensation on the jar, and precipitation as water
droplets fall, or run down, the sides of the jar.
Blackline Master #16, Experiment #5: Transpiration
1. We find water in the bags.
2. The water comes from the leaves of the plant. It traveled up
from the ground in the plant's roots.
3. Leafy plants and trees should transpire more than those with
needles.
4. Over time, it is possible to get enough water to drink, especially
if you use multiple bags.
Blackline Master #17, Experiment #6: Frost
1. Tiny crystals of ice are in the bag.
2. The ice crystals came from the vapor that was in your breath.
3. This is the process of condensation.
4. After a half hour, we see water droplets from the melted ice.
5. There is moisture in our breath and in our bodies.
Blackline Master #18. Experiment #7: Salty Water to Fresh
Water
1. Water condenses to form droplets in the tube.
2. The empty bottle receives water from droplets falling from
the tube.
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3. Dark colors absorb more heat. Warmer water evaporates
faster, so it speeds up the process.
4. The water in the clear bottle should not be salty.
5. Desalination or distillation.
Blackline Master #19, Experiment #8: Holding Heat
1. The thermometer in the empty cup cools fastest.
2. Heat from outside the refrigerator will change the readings
on the thermometers.
3. Yes, both thermometers should end up at the same temperature.
4. The thermometer in the empty cup warms fastest.
5. Water is dense and it has a high capacity to retain heat.
6. Cities near large bodies of water are more likely to have a
climate where the temperatures don't change very fast or very
much, compared to cities not near large bodies of water.
EXTENDED LEARNING ACTIVITIES
• Tour a golf course with a groundskeeper to hear how he or she
maintains the greens and how things such as rainfall, sunlight,
dew, type of grass, angle of slopes, fertilizers, and pesticides are
all a big factor.
• A field trip to a nearby National Weather Service office will
introduce the students to people who focus on water's role in
weather and climate. Aside from forecasters, many offices
employ a hydrologist.
• Visit the local water utility to see how they secure fresh water
and provide it to your community.
• Invite a local TV weather forecaster to talk about the water
cycle and some of the extremes it produces in your area.
• Ask a person from a city or county parks department to lead a
field trip through a park where the students can observe the role
of the water cycle in plants, and in erosion.
15

SCRIPT OF NARRATION
Water is as old as the Earth. As far as we know, the amount of
water on Earth has never changed. That's amazing when you
think that the water in your faucet may have been deep in the
sea millions of years ago. Or it may have been in a glacier for a
thousand years. When you are done with it, it goes down the
drain, and sooner or later, back to a lake or ocean where it may
rise up into the sky and form a cloud that travels around the
world to be used again.
All over the planet, the sun helps nature recycle water in the
water cycle. The water cycle has three main parts. Evaporation
is when water turns into invisible water vapor and rises into the
air. Condensation is when water vapor forms clouds, dew, or
frost. And precipitation is when water falls from clouds as rain,
snow, sleet, or hail. There's also a fourth part to the water cycle.
It's called runoff; and that's when water runs downhill to flow
into streams, lakes, or oceans. In the water cycle, we see water's
different forms and properties. It can be solid ice that does not
change shape, liquid water that moves and flows, or water
vapor that floats in the air.
The parts of the water cycle can control the climate of cities
worldwide. Some places stay warm and wet, while others stay
cold and dry. The water cycle is like an engine and the fuel for
it is heat from the sun. The more heat that comes from the sun,
the faster the water cycle works. At night, and even in places
where you don't have much heat, the water cycle continues as
liquid water, changes to ice, or water vapor, and back again. We
call these phase changes. The water cycle makes sure that clean
water falls from the sky and is spread around the Earth in one
way or another. This makes it possible for people, plants,
insects, and animals to survive and live almost anywhere.
Evaporation is when tiny water droplets rise into the air as clean
water vapor. Heat from the sun makes evaporation go faster.
That's why, if you heat a pot of water for a long time, it turns to
16

steam and the water disappears. Moving air or wind also speeds
up evaporation. Water vapor is invisible, but when there is a lot
in the air, we feel the moisture on our skin. In the summer, people
say the air is humid when it is filled with water vapor. After
the rain ends on a warm day, we watch how quickly puddles
and pavement dry off as the water evaporates. From salty
oceans, lakes, and even swimming pools, water evaporates as
fresh water. It is not always easy to notice when water is deep,
but if you watch closely and take measurements, you'll find that
all water evaporates into the air.
Water that is in the ground can also evaporate, but that is slower
since soil particles get in the way.
Trees and plants help water turn into water vapor through transpiration.
Transpiration is when the leaves of plants give off
water that evaporates into the air. In a forest, transpiration plays
a big part in the water cycle. The roots of plants, bushes, and
trees pull water out of the ground, and then the leaves allow it
to escape. You can do a simple experiment to prove this. Just
put a clear bag over some leaves of a tree or bush, for an hour.
Examine it and you'll find clean water.
Did you know that ice can turn directly into water vapor without
melting first?! When ice turns straight to water vapor, that's
called sublimation. Sublimation is how snow can disappear
after a few days, even when the temperature stays below freezing.
It doesn't melt. It changes directly to vapor. You can see
this by leaving ice cubes in your freezer for a few weeks. Notice
that they gradually get smaller and smaller as the ice changes
phase from solid to vapor.
Condensation is when water vapor changes to a bunch of tiny
water droplets that we see together as clouds. Sometimes these
clouds are made of crystals of ice instead of water droplets.
Condensation happens when air cannot hold any more water
vapor. To make condensation, just keep filling the air with
water vapor by evaporating more and more of it. When we
shower, many of us make condensation clouds.
17

The clouds that nature creates take on many shapes, sizes, and
colors. They form at any height and sometimes they even form
on the ground as fog. These clouds make it easy for wind to
push a lot of water around the Earth to places that need moisture.
Clouds can keep us cool by blocking sunlight during the
day.
Another way to make condensation is to cool the air. This can
happen when wind blows over cool water or cool land, or when
air rises up the side of a mountain.
There are two special kinds of condensation where no cloud is
formed. They both happen after a clear night, with calm wind.
Sometimes we wake up to find small beads of water on grass,
or cars. That's dew. When the temperature is below freezing you
might see ice crystals instead, especially on windows. That's
frost. You can tell that it didn't fall from the sky because the sky
is clear. Dew and frost happen when the temperature cools
down and the air can't hold any more water vapor. In deserts,
these are important ways for plants, insects, and animals to get
water. You've probably noticed that after you take something
out of the refrigerator, you see water droplets form on it. We
also notice condensation on a glass of ice water. When you take
something out of the freezer, you find ice crystals on that.
As clouds get thicker, the water droplets inside of them grow
heavy enough to fall. Water or ice that falls from clouds is
called precipitation. Precipitation is rain, snow, sleet, or hail.
Rain can cool off a hot city, help to fill a reservoir, and supply
water to ecosystems. Too much rain causes problems. Lakes’
levels can rise and flood people's homes. Flood water can
drown animals, people, and even plants and trees. The places on
Earth that get the most rain are near large bodies of water, near
the equator. Away from the equator, snow falls in layers to keep
the ground from getting too cold. Too much snow at once can
stop us from getting where we want to go. Snow that piles up is
very heavy, and it may damage tree branches and property.
Sleet is half frozen rain or half melted snow that can make a
18

slushy mess. Hail is pieces of ice that fall from powerful thunderstorms.
When hail is large, it damages plants, crops, trees,
and rooftops. All precipitation delivers water to the Earth's surface.
A scientist who predicts precipitation is called a meteorologist.
Runoff describes what happens to precipitation after it hits the
ground. It simply will run off, downhill. Of course if it is snow,
sleet, or hail, it has to melt first, but a lot of the water that falls
from the sky flows in streams and rivers until it ends up in a
lake or ocean. When water runoff is always in the same path or
when it is very heavy and fast, it carries pieces of soil and rock
and moves them downhill. That's called erosion. You can see
erosion by spraying water onto a pile of sand. Runoff from
heavy precipitation can be destructive. It can fill streams with
solid soil pieces, called sediment, that make it hard for fish to
breath. Heavy runoff can also carry pollution great distances. It
can muddy the water so plants have a hard time getting sunlight
to remain healthy. Runoff may weaken tree roots.
It's always worse in cities with a lot of pavement. Runoff is also
heavy in fields where there is little grass or plant life to help
slow the water and soak it up. It's a good idea for any construction
area to use fences to keep soil and pollutants from being
washed away.
Precipitation that does not run off slowly soaks into the soil.
This is called percolation. If the ground is sandy, water can percolate
into it pretty fast. When the ground lets water soak in
fast, we say it is porous. But if the ground has a lot of clay in it,
then it's not very porous and the percolation will be slow. As the
water sinks into the ground, the soil and plants help to filter it
and clean it. You can demonstrate how porous something is
using muddy water, cotton balls, and a funnel. Pour the water
into the cotton in the funnel to see how fast it moves through
and to see how much of the sediment the cotton can catch.
Water that percolates down into the ground is then called
groundwater.
All forms of water take a lot of heat from the sun to slowly
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warm up. Once water is warm, it takes a long time to cool
down, so all parts of the water cycle control temperature, precipitation,
and climate. Climate is the average kind of weather
that a place has. Islands with a lot of sunshine near the equator
have climates that are humid and rainy because the sun's heat
speeds up evaporation, condensation, precipitation, and runoff.
All parts of the water cycle are connected.
In sandy deserts, dry climates include hot days and cold nights.
Without much water from the water cycle, it's easier for the
temperature to rise and fall fast.
Water plays an important role on Earth in weather and climatic
patterns. Runoff from precipitation can wear things down in
erosion, and carry them away. Water can also dissolve anything
that sits in it long enough, so we call it the universal solvent.
This makes water valuable in keeping ecosystems healthy.
The water cycle produces climates where humans and animals
can live and find fresh water.
Now that you are Water Smart, let's take a quiz. True or False:
Number one. The water cycle stops at night.
Number two. Hail is a type of precipitation.
Number three. Percolation helps to clean water.
Number four. Dew is condensation.
Number five. There is no water cycle where it is cold.
Number six. Evaporation is faster when it is warm.
Number seven. Snow helps to deliver fresh water.
Number eight. There is no water anywhere in a desert.
Number nine. There is more runoff on pavement than on grass.
Number ten. Plants help out in the water cycle.
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