Water Cycle Webquest: Student Capture Sheet ANSWER KEY
Go to http://pmm.nasa.gov/education/interactive/water-cycle-webquest to find this
webquest. Use this student capture sheet to provide your answers to the questions.
Before you begin this webquest, answer these questions using your background
knowledge.
 How much of Earth’s surface is covered by water?
 How much of the water on Earth’s surface is actually freshwater?
 Where does the water that we use to meet our everyday needs come from?
GPM is an unmanned satellite that will be launched in February 2014. Here is an
introductory video to give you a sense of what it will do and why the science behind the
mission is so important. http://pmm.nasa.gov/education/videos/gpm-freshwaterconnection
 Where does the water that we drink come from? From precipitation
 Why is it important for scientists to measure how much precipitation is falling
across the world? “Understanding how much snow is falling is important for
transportation, safety, how much freshwater falls and is stored in snowpacks.”
 How could that information be used to help society? We could use the
information to help us predict natural disasters and to see where the freshwater
resources are so we can make sure people have enough water to drink and use
for agriculture.
Let’s begin by following a molecule of water as it makes its way through the water cycle
in this short animation. http://pmm.nasa.gov/education/videos/tour-water-cycle
 Is there a specific beginning or end in the water cycle? Why or why not? There
really isn’t an actual beginning or end as it is a cycle. It doesn’t matter where in
the water cycle a droplet of water is because it will go through all of the stages
again and again.
 What “powers” the water cycle? The sun
Scan the article titled, “The Water Cycle” from to answer the questions below.
http://earthobservatory.nasa.gov/
 How much of Earth’s water is found in our oceans? About 96.5%
 How much water is stored in polar icecaps, glaciers, and permanent snow? 1.7%
 How much water is stored in groundwater, lakes, rivers, soil, and streams? 1.7%
 Why is the amount of freshwater on Earth important for human needs? We need
it for our agriculture and to drink.
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Next, click on “A Multi-Phased Journey” at the bottom of the page, and use that
information to do the following:
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Look at the diagram of the hydrologic cycle, and use it to help you to write a
paragraph that explains how a droplet of water that falls as rain can move
through the atmosphere, the biosphere, the geosphere, and the hydrosphere. Be
specific as you explain the processes (evaporation, condensation, transpiration)
that occur because of interaction between Earth’s spheres.
In your response, be sure to
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Give the state of matter that water is in as it moves through Earth’s systems
Describe what processes occur to change water from one state of matter to
another
Explain how interactions between Earth’s spheres keep water cycling between
them
Example of a thorough response:
A droplet of water falls to the Earth as rain as it moves through Earth’s atmosphere,
biosphere, geosphere, and hydrosphere. As precipitation is a form of water, it is part of
the hydrosphere, as all water on Earth; solid like ice, liquid like rain, or in a gas like water
vapor; are part of Earth’s hydrosphere. The droplet of water is in the liquid form as it
falls through Earth’s atmosphere, which is the blanket of gases surrounding Earth. If it
falls onto a farmer’s crops, then it provides water to help the crops grow. The crops are
part of the biosphere, which includes the living things on Earth. When people eat the
crops, then that water also goes into another part of the biosphere. When the sun
shines and adds heat to the geosphere, Earth’s land surfaces, the water droplet may get
so hot that it evaporates into water vapor, and is now a gas. This also will happen to the
water that is in the crops when it gets hot enough, and it will turn into water vapor, in a
process known as “transpiration”. Now the water, in the form of a gas, has evaporated
into the atmosphere. As the water vapor comes together, clouds may be formed, and
the water becomes liquid or solid as the temperatures decrease. Clouds form, and
eventually gravity causes the water to fall back to Earth in the form of a solid; as hail,
sleet, or snow; or as a liquid, as rain. The same water will continually cycle through
Earth’s atmosphere, geosphere, and biosphere in the forms of a liquid, a gas, or a soliddepending on the temperature.
Let’s learn more about how our water cycle is able to distribute both water and heat as
it moves through the water cycle: http://pmm.nasa.gov/education/videos/earths-watercycle.
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Where is more than two-thirds of Earth’s freshwater stored? in Earth’s polar ice
caps, snow packs, or glaciers
Why is there more evaporation in the tropics? The ocean temperatures are
warmer there, and thus more water is evaporated
Why do you think that clouds and water vapor act like “insulators” from the
sun”? The water vapor makes up the clouds, and the clouds help to shield the
Earth from the Sun, and trap the heat from below.
What are two things that water variability affects for us?
1. The type and amount of vegetation, which is the primary source of food for
people and animals.
2. Causing extremes, such as droughts or floods, which can result in both
economic and human losses
At this website, http://pmm.nasa.gov/education/videos/water-cycle-heating-ocean, you
will find out more about how the oceans impact the water cycle.
 How are the land, air, and water heated each day? They absorb sunlight and are
heated.
 Look at the second animation. Explain the differences that the data shows
between the heating of the land and the water during the day and night cycle.
The land surfaces get warmer after the sun rises, and cool off fairly quickly after
the sun sets, while the ocean surface temperature doesn’t vary much at all from
day to night.
 Look at the third animation. Explain how the movement of warm currents might
affect the climate in Florida. The climate in Florida will be warmer than other
parts of the US throughout the entire year because the warm tropical water is
being pushed toward Florida throughout the seasons.
The next website will focus on how evaporation and winds combine to move water from
the oceans to the land. http://pmm.nasa.gov/education/videos/water-cycle-steamingair
 How does the ocean lose water to the air? Water from the ocean evaporates
into the air
 Why doesn’t the water vapor just stay over the ocean? Winds spread the water
vapor across the globe
 Why don’t the oceans simply reabsorb the water that evaporates? The water
vapor is moved by the winds and ends up over other parts of the world
 Why does more water evaporate off of oceans than off of land? Because the
oceans cover almost 75% of the Earth’s surface, so there is a lot more ocean
water than water on land to evaporate
 About how long does water vapor remain in the air? An average of 10 days
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As you watch the animations depicting wind and evaporation data over the
world, describe what you notice about the patterns the winds and clouds follow:
Do clouds and wind appear to follow the same patterns? Can you find any
patterns in the direction that they move? Both the winds and the clouds move in
the same directions. In the northern hemisphere between North America and
Asia, the winds move from west to east near the equator, and then circulate
around clockwise and move from east to west in the higher latitudes.
We know that everything needs freshwater to survive. Go to this site and find the
answers to these questions:
http://www.epa.gov/WaterSense/our_water/water_use_today.html
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Where does the freshwater that you use in your home come from? From
precipitation
About how much water does the average American family of four use per day in
their home? About 300 gallons
What percentage of water do we use for washing our clothing? 21.7%
What percentage of water do we use for flushing our toilets? 26.7%
Look at the pie graph depicting how freshwater is used for industrial, agricultural, and
electric water use, and use that information to answer these questions.
 What percentage more of water is used to provide us with electricity versus for
irrigation? 41.5 – 37 = 4.5% more
 Do we use more freshwater in our homes or to provide us with electricity? We
use a lot more freshwater, about 41.5%, to provide us with electricity than in our
homes, which is about 8.5%.
At this website, http://pmm.nasa.gov/education/videos/water-cycle-watering-land you
will find out the processes of condensation and precipitation. Read the description, and
then answer these questions.
 How do clouds form? Clouds form as water vapor rises, cools, and condenses
into little water droplets.
 What role do clouds play in regulating Earth’s energy balance? Clouds reflect
sunlight away from Earth
 About how much of Earth is covered by clouds at any one time? About 50%
 What is the ratio of water than falls on land as compared to the amount that falls
onto the oceans? About 100 trillion tons of water over land compared to 400
trillion over water, so 1:4
As you watch the animations, watch the direction that the wind is blowing in.
 Does the direction change in different regions of the world? yes
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How does the direction that the wind is blowing in affect how much precipitation
the Eastern seaboard of the United States gets per year? There is wind blowing
down from Canada as well as blowing in from the Atlantic Ocean. Both of these
wind patterns converge at the Eastern seaboard, and cause a lot of precipitation
to occur in this area and just off to sea in the Atlantic Ocean.
Why do you think the northern part of Africa doesn’t receive very much
precipitation per year? There appears to be very little ocean water vapor that
gets blown over the northern part of Africa, and so it receives very little
precipitation.
Now sit back and enjoy this video about the water cycle and the importance of water to
life on Earth. http://pmm.nasa.gov/education/videos/water-water-everywhere
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What is special about water as a compound? It is the only compound that can
be found naturally as a liquid, gas, and solid.
How does water regulate climate? By storing heat during the day and
releasing it during the night, and by carrying heat from the tropics to the
poles
What drives water evaporation? Heat from the sun
Why is the water vapor fresh water when it rises from the ocean? The salt
stays behind in the ocean
Why might freshwater in the form of snow take longer to enter the water
cycle again than liquid precipitation? It may stay locked in a glacier or an ice
sheet or in the soil for a long period of time.
What is an aquifer? Any underground storage area for water
What role do people play in the water cycle? Pumping water out of the
ground for irrigation, cutting down forests for development, and building
roads, when we control the water after it has fallen, putting in dams
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