Name____________________________________________________Block________
Before you begin the Water unit, mark each statement with a T for true or an F for false.
At the conclusion of the unit, mark the statements again to show what you have learned.
STATEMENT
Before
After
1. Adhesion is when water molecules attract to other water molecules.
T
F
T
F
2. A water molecule has 10 electrons.
T
F
T
F
3. Rocks being cracked by freezing water is called frost wedging.
T
F
T
F
4. Most of the Earth’s surface water is fresh water.
T
F
T
F
5. Much of the Earth’s fresh water is found in aquifers.
T
F
T
F
6. A solute is the most abundant part of a solution.
T
F
T
F
7. Solubility is the maximum amount of a solute that can dissolve in a solvent.
T
F
T
F
8. Cohesion is when water molecules stick to other surfaces.
T
F
T
F
9. Precipitation is rain, snow, sleet, or hail.
T
F
T
F
10. The majority of Earth’s water is used for agricultural purposes.
T
F
T
F
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3
Directions: Define the following terms. You will be quizzed on you knowledge of the
vocabulary.
Term
adhesion
aquifer
cohesion
condensation
density
Definition
the property of water molecules to be attracted to other materials
a deep underground source of water contained within a layer of rock, sand,
gravel, silt, or clay
the property of water molecules to be attracted to other water molecules
when water vapor liquefies to form fog, clouds, or rain, or solidifies to form snow
or hail; changing from a gas to a liquid or solid
amount of mass per volume; amount of “stuff” per volume of a material
desalination
processes that remove excess salt and minerals from water
evaporation
the changing of a liquid into a gas
hydroelectric
electricity created using the force of falling water
power
precipitation
falling products of condensation in the atmosphere (rain, snow, sleet, or hail)
solubility
maximum amount of a solute that can dissolve in a given amount of solvent
surfactant
any substance that when dissolved in water reduces its surface tension
surface
tension
weathering
attraction of water molecules at the surface of a body of water
physical or chemical processes that cause exposed rock to break down
Directions: After assembling your water molecule model, use it to answer the following
questions.
1. How many electrons does a hydrogen atom have?
_____
2. How many electrons does an oxygen atom have?
_____
3. How many electrons does a water molecule have?
_____
4. What charge does the hydrogen end of a water molecule have? _______________________
5. What charge does the oxygen end of a water molecule have?
_______________________
4
Directions: Assemble the parts to your water molecule on the page, then glue.
5
Have you ever filled a glass to its rim with water? What did you notice? The water forms
a “dome” that appears higher than the rim itself. This is due to the
water’s surface tension (see Fig. A). Surface tension is created
by water molecules being attracted to other water molecules, or
cohesion. The hydrogen end of a water molecule is positively charged.
The oxygen end of a water molecule is negatively charged. Just like
magnets, opposite sides, or charges attract (see Fig. B). If you’ve ever
seen an insect moving on top of water, then you have seen surface
tension (see Fig. C). Water is also attracted to molecules of other
substances, and this is called adhesion. In Figure D, you can see water
molecules attracting to the spider web.
6
Water is called the "universal solvent" because it dissolves more substances than any
other liquid. When one substance is dissolved into another substance it is a solution.
The most abundant part of a solution is the solvent. The least abundant part of a solution
is a solute. Take, for example, lemonade; the lemonade mix (solute) is dissolved in water
(solvent). Solubility is the maximum amount of a solute than can dissolve in a given amount of
solvent. So, let’s say, to a gallon of water, you kept adding one scoop of lemonade mix until no
more could be dissolved. You would now know the solubility of the lemonade mix.
When water vapor evaporates, it cools and condenses in the atmosphere. The
condensation make take the form of rain, snow, sleet, or hail. These forms of
precipitation fall to the ground to begin the water cycle again.
DIRECTIONS: Use the bold words above to fill-in the blanks below showing the steps of the water
cycle.
The water vapor
__________________ and
_____________________
into water droplets, snow, sleet or hail.
_________________________ from
the land and air rises into the sky
This _________________________ falls to
the ground.
after being heated by the sun. This is
called _______________________.
7
Weathering is the processes at or near the Earth’s surface that breakdown rock into
sediment, or soil. There are three types of weathering: physical, chemical, and biological.
Water plays an important role in weathering.
Frost Wedging
Freezing water can break rock into smaller
pieces. Water enters cracks in rocks, freezes,
then expands. This expansion of water produces
enough force to crack rocks apart. Potholes in
roads and cracks in rocks are often caused by the
repeated freezing and expansion of water in small
cracks.
Frost Wedging
1. Water seeps inside cracks & pores of rock
2. Water freezes, expands, & wedges rock apart
3. Rock breaks
Chemical Weathering
Water or rain water containing minerals and dissolved
gasses like nitrogen and sulfur oxides form a weak acid (acid
rain) that react with minerals in the rock to dissolve or
change them. Limestone caves and caverns are formed this
way. The concrete in buildings may also be dissolved over
time.
Limestone Weathered by Water
Acid Rain
8
Predict the percentages of salt, fresh, and frozen water that are on the surface of the
Earth. Make a color coded key to explain your circle graph.
Salt
Fresh
Frozen
9
Graph the actual percentages of salt, fresh, and frozen water that are on the surface of the
Earth. Make a color coded key to explain your circle graph.
Salt
Fresh
Frozen
10
Seventy-percent of the Earth is covered in water. Of that, 97% is salt water, 2% is frozen
water (glaciers), and a small 1% is fresh water. Much of our fresh water is stored in deep
underground layers of rock, sand, silt, gravel, or clay called aquifers. You must drill down
into the Earth to reach an aquifer, or water reserve. Aquifers can, and are, being emptied by
increased use of water.
11
Our fresh water must be treated before drinking. Water treatment plants are responsible
for doing this. The steps in treating water are:
12
You will use the United State Geological Survey’s handout to investigate water usage in
the United States.
First, take five minutes to brainstorm as many ways you can think of that we use water. Then you
will share your thoughts with your group members.
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1. List the uses for water and the percentage given for each use. Use this data to complete the
circle graph. This information can be found in Figure 1 on page 5.
Water Use in the United States (2005)
Use
Percentage (%)
2. How much water per day was used by the United States in 2005?
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3. What is thermoelectric power?
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4. How much freshwater does Virginia withdraw for thermoelectric power?
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5. How much water does Virginia withdraw for public-supply use?
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6. How much water does Virginia withdraw for irrigation?
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7. How much freshwater does Virginia withdraw for industrial reasons?
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8. What four states use the most water? Why do you think is the reason for this high amount?
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9. Why do you think we need to protect our water supply?
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10. How can we protect our water supply?
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Graph the data for the uses of water. Write the name for each use on the correct circle
graph piece.
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