SEPA
United States       Office of Water
Environmental Protection  4601
Agency
                                   EPA 570/9-90-007
                                   ApriM990
Science
Demonstration
Projects  in
Drinking Water
(GradesK-12)

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                                  i lit  r od  u ct ron
This pamphlet includes a brief selection of science demon-
stration projects related to drinking water for K-12 students.
The projects are organized according to the following grade
categories: primary (K-4); middle/junior high (5-8); and
secondary (9-12).  The divisions between  grade categories
are arbitrary. The projects are essentially  applicable  to all
grade levels. By simply varying the vocabulary and expand-
ing or contracting the background and discussion sections,
each project can be made relevant to a specific grade level.

The general areas covered by the demonstration projects
include the chemical/physical aspects of water, contamina-
tionand treatment of drinking water, distribution and supply
of drinkingwater,andwaterconservation. While the projects
presented are complete activities, teachers are encouraged to
expand the projects to meet the needs and goals of their
respective teaching situations.

The demonstration projects included in this pamphlet are
representative of many such projects developed by talented
professionals in the science, engineering, and education
communities. The projects have been reprinted in whole or
in part with the permission of the appropriate publishers.
Reference and/or credit information is included with each
activity. In addition, a list of organizations that have devel-
oped or are developing projects related to drinking water are
included at the back of this document.

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             pir  i m a  ry
          The Never Ending
             Cycle of Water
Background
Water is very abundant on Earth. It circulates continu-
ously between the air, the ground, and plants and
animals. This constant circulation of water is known as
the water cycle. Water is carried through air where it
eventually condenses into small droplets which form
clouds. From the clouds, water falls to the Earth in the
form of rain or  snow (precipitation). This water is
absorbed into the ground or runs over the surface of the
ground into rivers and lakes. Plants and animals use the
water to live. Water then evaporates from soil, the
leaves of plants, the lungs and skin of animals, and from
the surface of puddles, streams, and lakes to the air.
Woodland plants (e.g., violets, ferns, or mosses—gathered in
backyards or available from nurseries)
Water
Light source or a sunny window gill
Tight-fitting jar lid (or plastic wrap secured by rubber band
or masking tape)

Procedure	

1)  Place a one-inch layer of gravel on the bottom of
    the clear glass jar. Cover this layer with one of
    sphagnum or peat moss, followed by a layer of
    soil (see illustration at right).
2)  Set woodland plant(s) into the soil mixture.

3)  Water terrain lightly.
 4)
    Evaporation
Cover glass jar tightly with lid (if available) or
with plastic wrap secured' by a rubber band or
                     masking tape and place
                     urtder or near a light
                     source.
                     5)  Observe the glass jar
                     over several hours.

                     Discussion
 Objective
 To demonstrate that water moves in a continuous cycle.
                                                     Source: Science Activities for Children
 Suggested Activities
                         DWhat collected  on the
                         sides of the glass jar? (con-
                         densed moisture)

                         2) Where did the moisture
                         on the sides of the glass jar
                         come from?  (evaporated
                         water from plants)

                         3) What provided  the en-
                         ergy for the  changes ob-
                         served in the water's form?
                         (the sun)
 Materials
 Large, wide-mouthed clear glass jar
 Gravel*
 Sphagnum or peat moss*
 Soil*
 Prior to conducting this activity, the teacher may wish
 to more fully demonstrate the processes of precipita-
 tion, evaporation, and condensation.  In addition, a
 discussion or demonstration Of water in its three states
 (solid, liquid, gas) might also be useful. Samples of such
 experiments can be found in the source material noted
 below.
 '(available from hardware stores or nurseries)

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                                                                 primary
Sources
Activity #1
Background information adapted with permission from:
Willard J. Jacobson and Abby B. Bergman. Science Activities for
Children. (Englewood Cliffs, NJ: Prentice-Hall, Inc., 1983). p. 47.
Activity adapted with permission from:
Water Wizards. (Boston, MA: Massachusetts Water Resources Au-
thority. 1983). pp. 2-4.
"Water: We Can't Live Without It." National Wildlife Week Educators'
Guide. (Washington, DC: National Wildlife Federation, March 18-24,
1984). p. 7.
            Source: National Wildlife Week Educators' Guide
  How People Get Their Water
Background
Nearly 80 percent of the Earth's surface is water, yet less
than one percent can be used for drinking water. Water
moves in a continuous cycle between the air, the ground,
and plants and animals (see previous activity). Most
water does not naturally exist in a pure form or in a form
that is safe for people to drink. Consequently, water
must be cleaned prior to consumption. Water utilities
provide such treatment before water is sent through
pipes to homes in the community.

The demand for water by people varies. The availabil-
ity of water also varies in different areas of the country.
Consequent!)?-, utilities store extra water in spaces known
as reservoirs'. Water is usually contained in reservoirs
by a dam. Reservoirs help ensure that communities do
not run out of water at any given time regardless of the
communities' total water use.
Objective
To illustrate how a reservoir works.
Materials
Plastic box
Spray bottle
Pebbles
Soil
Sand
Leaves
                                                                                        Source: Water Wizards
Procedure
1)  Construct a model of a reservoir using a clean,
    clear plastic box (see illustration). Line the
    bottom of the box with small pebbles and then
    layer sand, soil, and leaves on top (sloping the
    material downward toward the edges f>f the
    box).

2)  Carefully spray  water on the four corners of the
    model until the  soil mixture is saturated and the
    water has seeped through to the open area—the
    reservoir.

Discussion
1)  What are the sources of water for a  reservoir?
    (precipitation in the form of rain and snow)

2)  How does water get into a reservoir? (It seeps over
    and through the soil above the reservoir.)

3)  What contains or holds water in a real  reservoir?
    (dams)

4)  What kind of treatment does water receive in a
   . reservoir? (natural filtration through leaves, grass,
    and soil; also some settling occurs in the reservoir)

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             p  r i  m ary
Activity #2
Source
Oblectlve                                          Achvities adapted with permission from:
To build a model of a water delivery system from source  water Wizards. (Boston, MA: Massachusetts Water Resources Au-
to user,                                           thority, 1983). pp. 10-14.

Materials
Large piece of paper or cardboard
Paper towel tubes
Different sizes of pasta (linguini, spaghetti, manicotti)
Glue
Reservoir built in Activity #1 (optional)

Procedure
1)  Using the pasta and paper towel tubes, create a
    community pipe system (see illustration). Connect
    the "pipes" with glue and lay out on the large sheet
    of paper or cardboard.

2)  Either use the reservoir constructed in the previous
    activity or draw one on the cardboard; also draw
    houses, schools, and other buildings that receive
    water from the delivery system.

Discussion
Students should  consider how water gets from reser-
voirs to distribution systems and to individual homes.
(The circumference of pipes decreases as the distribu-
tion system expands into the  community. As water
travels through a distribution system, it is continuously
diverted down different  pathways. These pathways
lead to individual homes and businesses. The circum-
ference of a pipe determines the quantity of water that
can be contained in the pipe at any one time arid deter-
mines, in part, the rate at which the water will travel
through the pipe. As the distribution system expands
to homes and businesses, the volume of water needed
per home or business represents only a portion of the   Background
total volume leaving the treatment plant. Consequently,
smaller pipes are needed in these areas of the distribu-
tion system, whereas larger pipes are needed near the
 treatment plant. Water treatment plants generally pump
water from the reservoir to holding or water towers.
The water flows by gravitational force from the water
 tower and throughout the distribution system.)
                                   Source: Water Wizards
       Conserving Water for
               The Future
Water is very valuable to us. We all need approximately
2 liters of water each day. We can live several weeks
without food, but can only live several days without
water. Water makes up our body's blood (which is 83%
water), transports bodily wastes, and helps us digest
our food. We get most of our body's daily requirement
of water from food. But water  is a limited resource,
which means that there is only so much water on Earth
available for use. In order for water to be available when
needed, it must be conserved.

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                                                               primary
Objective
To emphasize the need for water conservation.

Materials

One 12 ounce clear glass
Water
Question and answer sheet for each student

Procedure 	__^

1)  Explain to the students that they are conducting an
    experiment that will test what it is like to not have
    a drink of water. Inform the students that they may
    not drink water the entire morning or afternoon
    preceding the conclusion of the activity.

2)  Place the glass of water on a desk in the front of the
    classroom to visually remind students of water.

3)  About one half-hour before lunch or the conclusion
    of the school day, provide students with  the
    following questions to answer individually or as a
    group.


Discussion

1)  An average glass can hold 12 ounces of a liquid
    such as water. An average drip from a sink can
    waste 5 gallons of water per day or 240 ounces per
    day. How many glasses of water could be saved
    per day by fixing the leak? (Answer: 20)

2)  An average bathtub uses 36 gallons of water while
    the average short shower uses only 25 gallons — a
    difference of 11 gallons or 1408 ounces. Approxi-
    mately how many glasses of water could be saved
    if a person took a short shower instead of a bath?
    (Answer: 117.3)

3)  Do you think that some glasses of water could be
    saved if people filled dishwashers or washing
    machines with partial rather than full loads? (No.
    Most dishwashers and washers use  the same
    amount of water, no matter if there is a full or
    partial  load; in some models the cycle can be
    changed.)
4)  What other conservation measures can you think
    of that would save glasses of water? (Answers will
    vary.)

5)  How thirsty do you feel after not receiving water
    the entire morning or afternoon?  (Answers  will
    vary.)

6)  How do you think you would feel if you could only
    have several ounces of  water each day? (Very
    thirsty, sick, and eventually dead.)


Suggested Activities

Many other activities can teach students about water
conservation, including "water audits" of personal,
family, and even school-wide water use. A variation of
the "Water Use Analysis" project presented later in this
pamphlet may be appropriate to demonstrate how
people use water differently. A discussion of how vari-
ous cultures (e.g., desert versus city dwellers) value
water as well as spend time and effort obtaining it might
also be useful.

Source    	^_	

Activity adapted with permission from:

Water and Water Conservation Curriculum. (Aurora, CO: Aurora
Utilities Department), p. 197.
                                                -5-

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              m  id  die
        How Substances are
         Measured in Water
Background
We often find references to parts per million, parts per
billion, and even parts per trillion in our everyday
reading and news reports. What do they mean? Most of
us have difficulty imagining large numbers of objects.
How many stars can you see in the clear night sky far
away from the smog and lights of the city? What does it
mean when we read that an insecticide has been found
in our groundwater at a concentration of 5 parts per
billion? Developing an understanding of  extremely
large and extremely small numbers is very difficult.

Objective	
To visualize the concept of extremely small numbers.

Material	

1 bottle of food coloring

1 medicine dropper

1 white egg carton (6 or 12 eggs) or six small clear

  plastic cups

2 other containers to hold food coloring and water

Procedure	

1)  Prior to conducting the activity, ask students to
    consider the following:
    a)  What is the largest number of things you can
        clearly visualize in your mind? [Most of us can
        handle 5,10, perhaps even 20 if we use all of
        our fingers and toes.]

    b)  Can you visualize a group of 100 people? [Many
        people think they can by describing a party or
        community meeting. If you try to visualize a
        group of 80 or 120 differently from the 100, it
        soon becomes apparent that our visualization
        is not that clear. The Rose Bowl full of people
        represents about 100,000. Trying to pick out
        just 1 individual in that crowd would be find-
        ing 1 in 100,000.]

    c)  Food coloring from the store is usually a 10%
        solution. What does 10% mean? [It means 10
       parts (by weight) of solid food coloring dye is
       dissolved in 100 parts (by weight) of solution.
       For example, 10 grams of dye dissolved in 90
       grams of water make a total of 100 grams of
       10% solution.]

2)  Put some food coloring (5 or 6 drops from the
    bottle) into one small container and some tap water
    into the other.

3)  Use the medicine dropper ,to place one drop of 10
    percent food coloring (as it comes from the store)
    into the first container. [Since 10% means 10 parts
    of food coloring per 100 parts of solution, it is the
    same as 1 part food coloring in 10 parts of solution.]

4)  Use the medicine dropper to add 9 drops of water
    to the first container. Stir well. What is the concen-
    tration of the food coloring? [You have 1 drop of the
    original food coloring in 10 drops of the new solu-
    tion. Thus the concentration of the new solution is
    1/10 of the original. The original was 1 part in 10,
    so the concentration of the food coloring is now 1 /
    10 of 1 part in 10. This is 1 part in 10 x 10, or 1 part
    of food coloring in 100 parts of solution.]

5)  Use the medicine dropper to transfer 1 drop of
    solution to the next container. Add 9 drops  of
    water. Mix. You have again changed the concentra-
    tion by  a factor of one-tenth. What is the food
    coloring concentration in this container? [1 /10 of 1
    part in 100 is 1 part in 10 x 100, or 1 part in 1000 parts
    of solution.]

6)  Transfer one drop of the  1 part in 1000  parts of
    solution into the next container. Add 9 drops of
    water. Mix. What is the concentration? [1 part in
    10,000 parts of solution.]

7)  Continue to dilute 1 drop of each solution by add-
    ing water as before to obtain 1 part in 100,000 and
    then 1 part in 1,000,000. Your final solution is one
    part per million.

 Discussion
 1)   In which cavity do you first observe no  visual
     evidence that food coloring is present? [This gener-
     ally occurs in the final container, which is 1 ppm of
     food coloring.]

 2)   Since you cannot see any color present, how do you
     know there is indeed food coloring present?

 3)   Can you think of an experiment that you could do
     to prove there is food coloring present in each cup?
     Do it.

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                                                                middle
4)  Which is more concentrated, one part per million  Materials
    or 200 parts per billion? [A billion is a thousand
    million. Therefore, 1 ppm is 1000 ppb. 1 ppm is
    more concentrated than 200 ppb.]
Sources
Activity adapted with permission from:
Chemicals in Society Participant's Guide. (Berkeley, CA: Chemical
EducationforPublicUnderstandingProgram,UniversityofCalifor-  The story begins:
nia at Berkeley, 1989). pp. 5-6.
A schoolyard or large room with a water source
Two 122 L (32 gallon) trash cans
Empty milk jugs and/or buckets (as many as possible)
100 L of water
A watch or clock with a second hand
A meter stick (optional)
      Conserving the Nation's
           Water Resources

 Background                      	
 People require an average of 2 L of water per day to
 sustain life. However, the average American uses about
 100 times more water than this every day at home. An
 average family of four in the United States might use
 about 900 L of water per day for the purposes identified
 in the table below.
   Approximate daily water use by a family of
                 four in the U.S.
Use
Drinking and cooking
Dishwasher (3 loads per day)
Toilet (16 flushes per day)
Bathing (4 baths or showers per day)
Laundering clothes
Watering houseplants
Rinsing garbage into disposal unit
Total daily use:
Liters per Day
30
57
363
303
130
4
13
900 L
     (A reminder: 1 gallon = 3.8 L; 26.3 gallons
     daily water use of 900 L is equal to about 237 gallons.)
                                 Source: Earth: The Water Planet
  Objective
  To provide a real-life model of how much water a family
  typically uses on a daily basis; to allow participants to
  experience  firsthand how much effort is required to
  transport water; and to illustrate  that when  people
  desire, they can sharply reduce their water usage.
One cold January, the Smith family rent a house in the
mountains for a ski vacation, the house, though old,
has all the comforts of home — three bathrooms, a
complete laundry room, dishwasher, and garbage dis-
posal, plus a newly installed solar hot water heating
system. Unfortunately, the weather  gets so cold one
night that a water main in town breaks, and the Smiths
find out that the house will have no water service from
the local utility for the entire week. What should they do
— go back home or try to find another water supply?

Mr. Smith learns from a neighbor that there is an unfro-
zen spring 100 m from the house that could still be used
 for drinking water. Mrs. Smith, who is a mechanical
 engineer, discovers that if the municipal water  line
 coming into the house were shut off, the water in the
 storage tank for the solar water heater could be routed
 directly into the plumbing system. The water system in
 the house will work as long as the storage tank is kept
 filled with water from the spring.

 Mr. and Mrs. Smith discuss the situation with their two
 children Alice (14) and Sam (12). The family decides to
 form a "family bucket brigade" from the spring to the
 house, fill the storage tank each day, and continue their
 vacation. The storage tank can  hold about 900  L of
 water.

 Procedure	
 1)   Place the two trash cans 100 m apart (measure with
      a meter stick or the distance is equal to approxi-
      mately 150 paces for an average size adult).

 2)   Place 100 L of water in one of the trash cans. This
      can will represent the spring.

 3)   Select four students to represent the Smith family;
      equip each person with as many buckets and milk
      jugs as he/she can carry; and have students trans-
      fer the 100 L of water from the spring to the house
      (the house being represented by the second  trash
      can located 100 m away).
                                                 — 7 —

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              middle
4)  Have students record the time when the Smith
    family begins and finishes carrying the first 100 L
    of water. Students should then determine the total
    time that was required  for the Smith family to
    transfer all of the water.
5)  The Smiths may feel a little tired after transferring
    the 100 L of water. Thus far, they have only earned
    11 percent of the water required  to fill the tank.
    They still have 800 L to go. To save water (since this
    is role playing), have the Smiths bring the same 100
    L back from the house to the spring rather  than
    getting additional water out of the faucet being
    used.
6)  The Smiths should continue carrying the water
    back and forth until the 100 L of water has changed
    cans a total of nine times, and the Smiths have
    carried the equivalent of 900 L of water 100 m to the
    house.
7)  Have students record the time when the Smiths
    finish moving the entire 900 L of water from the
    spring to the house. Ask students the total amount
    of time (probably will be about 30 minutes) that
    was required to move the 900 L of water.

The story continues:

After carrying all of the water, the Smiths are too tired
to ski very much. They come home early, have spaghetti
for lunch, wash the dishes, and launder their bucket
brigade clothes (which got muddy at the spring). After
eating dinner, washing more dishes and clothes, water-
ing the houseplants, and taking long, hot showers, they
go to bed.
any leaking plumbing fixtures,, taking quick showers,
not flushing toilets after every use, reducing the amount
of water required for toilet flushing, etc.)


Source	_____	
Activity adapted with permission from:

Jack E. Gartrell, Jr., Jane Crowder, and Jeffrey C. Callister. Earth: The
Water Planaet. (Washington, DC: The National Science Teachers
Association, 1989). pages 85-89.
 It is snowing too hard the next day to ski, so the Smiths
 stay in the house all day. When Mr. Smith tries to start  Objective
 the dishwasher after lunch, he discovers that the family
 is out of water! Sam and Alice groan and say that they
 would rather be grounded until they are 21 than carry
 900 L of water to the house every day. They point out
 that they haven't even been in the house a full 24 hours
 since previously carrying the water.
        How Water Is Cleaned
 Background	

 Water in lakes, rivers,  and swamps often contains
 impurities that make it look and smell bad. The water
 may also contain bacteria and other microbiological
 organisms that can cause disease. Consequently, water
 from surface sources must be "cleaned" before it can be
 consumed by people. Water treatment plants typically
 clean water by taking it through the following proc-
 esses: 1) aeration; 2) coagulation; 3) sedimentation; 4)
 filtration; and 5) disinfection. Demonstration projects
 for the first four processes are included below.
 To demonstrate the procedures that municipal water
 plants use to purify water for drinking.

 Materials
 Discussion
 Have students identify and defend water conservation
 measures. What steps could the Smiths have taken to
 conserve water and  save  their ski vacation? (Some
 conservation  measures include washing clothes less
 frequently, running the dishwasher once per day, fixing
 5 L of "swamp water" (or add 2 1/2 cups of dirt or mud to
  5 L of water)
 One 2 L plastic soft drink bottle with its cap (or cork that
  fits tightly into the neck of the bottle)
 Two 2 L plastic soft drink bottles — one bottle with the top
  removed and one bottle with the bottom removed
                                                 -8-

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                                                                 middle
One 1.5 L (or larger) beaker or
 another soft drink bottle
 bottom

20 g of alum (potassium
 aluminum sulfate —
 approximately 2 tablespoons;
 available at a pharmacy)
Fine sand (about 800 ml in
 volume)

Coarse sand (about 800 ml in
 volume)

Small pebbles (about 400 ml in
 volume)
             Fine land
              Beaker
Source: Earth; The Water Planet
A large (500 ml or larger)
 beaker or jar

A small (approximately 5 cmx 5 cm) piece of flexible nylon
 screen

A tablespoon

A rubber band

A clock with a second hand or a stopwatch

Procedure

1)  Pour about 1.5 L of "swamp water" into a 2 L bottle.
    Have students describe the appearance and smell
    of the water.

2)  Aeration is the addition of air to water. It allows
    gases trapped in the  water to escape and adds
    oxygen to the water. Place the cap on the bottle and
    shake the water vigorously for 30 seconds. Con-
    tinue the aeration process by pouring the water
    into either one of the cut-off bottles, then pouring
    the water back and forth between the cut-off bottles
    10 times. Ask students  to describe any changes
    they observe. Pour the aerated water into a bottle
    with its top cut off.

3)  Coagulation is the process by which dirt and other
    suspended solid particles are chemically "stuck to-
    gether"  into floe so that they can be removed from
    water. With  the tablespoon, add 20 g of alum
    crystals fco the swamp water. Slowly stir the mixture
    for 5 minutes.

4)  Sedimentation is the process that occurs when
   . gravity  pulls  the particles of floe (clumps of alum
    and sediment) to the bottom of the cylinder. Allow
    the water to stand undisturbed in the cylinder. Ask
                     5)
    students to observe the water at 5 minute intervals
    for a total of 20 minutes and write their observa-
    tions  with respect to changes  in  the  water's
    appearance.

    Construct a filter from the bottle with its bottom cut
    off as follows (see illustration at left):
   a)  Attach the nylon screen to the outside neck of
       the bottle with a rubber band. Turn the bottle
       upside down and pour a layer of pebbles into
       the bottle — the screen will prevent the pebbles
       from falling out of the neck of the bottle.

   b)  Pour the course sand on top of the pebbles.

   c)  Pour the fine sand on-top of the course sand.

   d)  Clean the filter by slowly and carefully pouring
       through 5 L (or more) of clean tap water. Try not
       to disturb the top layer of sand as you pour the
       water.

6)  Filtration through a sand and pebble filter re-
    moves most of the impurities remaining in water
    after coagulation and sedimentation have taken
    place. After a large amount of sediment has settled
    on the bottom  of the bottle of swamp water, care-
    fully — without disturbing the sediment — pour
    the top two-thirds of the swamp water through the
    filter. Collect the filtered water in the beaker. Pour
    the remaining  (one-third bottle) of swamp water
    into the  collection bucket. Compare the treated
    and the untreated water. Ask  students whether
    treatment has changed the appearance and smell of
    the water. [Inform students that a water treatment
    plant would as a final step disinfect the water (e.g.,
    would add a disinfectant such as chlorine gas) to
    kill any remaining disease-causing organisms prior
    to distributing the water to homes. Therefore, the
    demonstration water is not safe to drink.]

Discussion	__

1)  What was the  appearance of the swamp water?
    (Answers will vary, depending on the water sou rce
    used. Water from some sources may be smelly
    and/or muddy.)

2)  Does aeration  change the appearance or smell of
    water? (If the original water sample was smelly, t he
    water should have less odor after aeration. Pouring
    the water back and forth allows some of the foul-
    smelling  gases trapped to escape to the air of the
    room. Students may have observed small bubbles
                                                -9-

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middle
                                    Source
    suspended in the water and attached to the sides of  Suggested Activities
    the cylinder.)

3)  How did  the sedimentation process effect the
    water's appearance? Did the appearance of the
    water vary at each 5 minute interval? (The rate of
    sedimentation depends on the water being used
    and the size of alum crystals added. Large particles
    will settle almost as soon as stirring stops. Even if
    the water contains very fine clay particles, visible
    clumps of floe should form and begin to settle out
    by the end of the 20-minute observation period.)

4)  How does the treated water (following filtration)
    differ from the untreated swamp water?  (After
    filtration, the treated swamp water should look
    much clearer than the untreated water. It probably
    will not be as clear as tap water, but the decrease in
    the amount of material suspended in the water
    should be quite obvious. The treated sample should
    have very little odor when compared to the starting
    supply of swamp water.)
                                          A field trip to a local water treatment plant.

                                          Have the State or a certified testing laboratory
                                          conduct analyses of the students' treated and
                                          untreated water for various contaminants.
                                    Activity adapted with permission from:
                                    Jack E. Garirell, Jr., Jane Crowder, and Jeffrey C. Callister. Earth: The
                                    Water Planet (Washington, DC: The National Science Teachers Asso-
                                    ciation, 1989). pp. 97-101.
                    How a  water treatment system  works.
                                                           ^•Chlorination
                                                                     Filtered
                                                                    f Water Storage
                                                  Source: The Official Captain Hydro Water Conservation Workbook

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                                                           Secondary
  Concentrations of Chemical

          Pollutants in Water

Background

Concentrations of chemical pollutants in water are fre-
quently expressed in units of "parts per million" (ppm)
or "parts  per billion" (ppb). For example, chemical
fertilizers contain nitrates, a chemical that can be dan-
gerous to pregnant women even in quantities as small
as 10 parts per  million. Trichloroethylene (TCE),  a
common industrial solvent, is more dangerous than
nitrates and when present in drinking water in quanti-
ties as small as 5 parts per million can cause a higher
than normal incidence of cancer among people who
drink the water regularly.

Objective

To demonstrate the concept  of ppm and ppb as these
units are used to explain chemical contaminant concen-
trations in water; to explain how chemicals may be
present in very small amounts in water such that they
cannot of ten be detected by sight, taste, or smell; though,
still possibly posing as a threat to human health.

Materials

Solid coffee stirrers or tooth picks
Clean water for rinsing the dropper
Medicine dropper
Red food coloring (for "contamination")
Set of 9 clear containers
Clean water for diluting
White paper

Procedure

1)  Line up the  containers side-by-side and place  a
    piece of white paper under each one. From left to
    right, number the containers 1 to 9.
2)  Place 10 drops of food coloring into container #1
    (food dye is already diluted 1:10).
3)  Place one drop of food coloring into container #2.
4)  Add 9 drops of clean water to container #2 and stir
    the solution. Rinse the dropper.
5)  Use the medicine dropper to transfer 1 drop of the
    solution from container #2 into container #3. Add
    9 drops of clean water to container #3 and stir the
    solution. Rinse the dropper.
6)  Transfer 1 drop of the solution from container #3 to
    container #4. Add 9 drops of clean  water to con-
    tainer #4 and stir the solution. Rinse the dropper.
7)  Continue the same process until all 9 containers
    contain successively more dilute solutions.
8)  Complete the discussion questions below.

Discussion

1)  The food coloring in container #1 is a food coloring
    solution which is one part colorant per 10 parts liq-
    uid. What  is the  concentration for each  of the
    successive dilutions? (Have students use the table
    below; each dilution decreases by a factor of 10—
    1/10, MOO, 1/1000, etc.)

2)  What is the concentration of the solution when the
    diluted solution first appeared colorless? (Usually
    occurs in container #6,1/1,000,000 or 1 ppm.)

3)  Do you think there is any of the colored solution
    present in the diluted solution even though  it is
    colorless? Explain. (Yes. The solution is still pres-
    ent but has been  broken down into such small
    particles that it cannot be seen.)

4)  What would remain in  the containers if all the
    water  were removed?  (Residue from the food
    coloring.)

Suggested Activities      	

1)  Allow the water in the containers to evaporate and
    have students record their observations on what
    remains in the containers.

2)  Discuss chemical contamination of drinking wa ter.
    Use the list of maximum contaminant levels (MCLs)
    on the following page for some toxic or carcino-
    genic chemicals in drinking water (as regulated by
Container No.
Concentration
1
1/10
2
V
3
V
4
V
5
V
6
V
7
V
8
V
9
V
                                                                                Source: Water Wisdom

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         secondary
    the U.S. Environmental Protection Agency). These  contaminated aquifers are quite costly.
    MCLs represent the maximum amount of a chemi-                               :
    cal that can occur in drinking water without the  Objective
    water being dangerous to human health. [Note:
    Some of the MCLs listed are subject to revision by
    EPA shortly.]
SubsUnca   Concentration (ppb) Substance Concentration (ppb)
 Arsenic          50        Nitrate             10,000
 Barium         1.000        Selenium
 Cadmium         10        Endrin
 Mercury          2        2,4-D (herbicide)
                                              To illustrate how water flows through an aquifer, how
                                              ground water can become contaminated, and how diffi-
                                              cult it is to clean up contamination.
                                         10
                                         0.2
                                         100
                                              Materials
Note: The above substances do not represent a complete list of
regulated drinking water contaminants.
3)
4)
Explain the relationship between ppm and ppb
and the conversion of these units to milligrams and
micrograms per liter. For example: 1 ppm = 1000
ppb; 1 ppm = 1 mg/1; and 1 ppb = 1 ug/1.
6"x8" disposable aluminum cake pans or plastic boxes
2 Ibs. non-water soluble plasticine modeling clay or floral clay
3-4 Ibs. white aquarium gravel
Pea gravel
Small drinking straw
Food coloring
6 oz. paper cups (no larger)
Water
Relate the  previous conversions to the drinking   Procedure
water regulations. [MCLs are established in milli-
grams per liter (mg/1)]. Convert the numbers in the
above chart from ppb to mg/1.
                                                   1)
 Source
 Activity adapted with permission from:

 Water Wisdom. (Boston, MA: Massachusetts Water Resources
 Authority, 1989). Exercise #16.
   Contamination of an  Aquifer

 Background	    •	

 Many communities obtain their drinking water from
 underground sources called aquifers. Water suppliers
 or utility officials drill wells through soil and rock into
 aquifers for the groundwater contained therein. Unfor-
 tunately, the groundwater can become contaminated
 by harmful chemicals that percolate down through soil
 androckinto theaquifer—and eventually into the well.
 Groundwater contamination by chemicals is caused
 mainly by industrial runoff and/or improper manage-
 ment of chemicals, including improper disposal of
 household chemicals such as lawn care products and
 cleaners. Such contamination can pose a significant
 threat to human health. The  measures that must be
 taken by utilities  to either protect  or clean  up
    Set up a model aquifer as shown in the diagram
    below. If a disposable aluminum baking pan is
    used, make a small hole in one end and insert a
    section of a drinking straw to serve as the drain
    spout. Seal the hole around the straw with glue or
    clay. In addition, seal the clay layers of the model
    against the side of the container.
2)  Place 10 drops of food coloring on the surface of the
    model near the highest end. This dye represents
    chemicals or others pollutants that have been spilled
    on the ground.
                                                   3)
                                                   Slowly pour one 6-ounce cup of tap water on the
                                                   aquarium gravel areas as shown in the diagram.
                                                   Collect the water as it runs out of the straw. Repeat
                                                   this process starting with 6 ounces of tap water and
                                                   continue the flushing process until all the food
                                                   coloring is washed out and the discharge water is
                                                         Add food coloring and flus|i water here.
                                                                                            spoul
                                               ]'t-a Cra
                                                              Aquurlum Crave!
                                    Clav I.:)} or


                                     Source: Water Wisdom

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                                                           seco  n d a ry
    clear. (Collecting the water in white paper cups or
    in test tubes held up against a white background
    will enable students to detect faint coloration.)
4)  Record the number of flushings required until an
    output with no visible color is reached (may re-
    quire up to ten flushes). [Note: 6 ounces of water in
    this model equals about 1 inch of rain.]

Discussion

Before the Activity
                                                  Source
                                                  Activity adapted with permission from:
                                                  Water Wisdom. (Boston, MA: Massachusetts Water Resources
                                                  Authority, 1989). Exercise #11.
                                                           Water Use Analysis
D
    Where does the water go that falls on the surface of  Backg rou nd
    an aquifer? How about any  chemicals or other
    pollutants that fall on the ground? (Some chemi-
    cals/pollutants are washed away by rain, some
    become attached to rocks and soil, and some end
    up in the groundwater.)
2)
    What things might influence the time needed to
    flush an aquifer clean? (Depth and volume of the
    water table, type of underlying rock and soil, nature
    and concentration of the pollutant.)

After the Activity
1)  After flushing, is the water in the model aquifer
    completely free of food coloring? (Probably not;
    trace amounts may remain.)

2)  Estimate how much contamination remains in the
    model aquifer. (Refer to previous exercise.)

3)  What keeps  the chemical contamination in the
    demonstration from reaching the lower levels of
    the model aquifer? (The clay layer.)

4)  What are some of the problems that might result
    from a major chemical spill near a watershed area?
    (Answers will vary.)
5)
    What steps could be taken to avoid damage to an
    aquifer? (Answers will vary.)
Suggested Activities
1)  Discuss the need for proper disposal of hazardous
    industrial wastes and harmful household chemi-
    cals, including used motor oil.

2)  Simulate nitrate pollution due to fertilizer runoff.
    Pollute the aquifer with a small amount of soluble
    nitrate and perform a standard nitrate test after
    each successive flushing (be sure to wear safety
    glasses).
Although household and other municipal water use
accounts for only about 9 percent of total water use in
the United States, delivering adequate quantities of
water of sufficient quality for this purpose is becoming
increasingly expensive for individuals and communi-
ties. It would, therefore, be useful for individuals and
communities to employ conservation measures when
using water.

Objective

To demonstrate the quantities of water that an average
family uses on a daily basis.

Procedure	

1)  Ask students to keep a diary of water use in their
    homes for three days. Students should make a
    chart similar to the one listed on the following
    page, adding any appropriate activities that are not
    listed.
2)  Ask students to review the table of average water
    volumes required for typical activities and  then
    answer the following questions using the  data
    from their three-day water use diary.
    a) Estimate the total amount of water your family
      used in the  three days. Give  your answer in
      liters.
    b) On average, how much water did each family
      member use during the three days? Give  your
      answer in liters per person per three days.
    c) On  average, how much water was used per
      family member each day? Give your answer in
      liters per person per day.
    d) Compare the daily volume of water used per
      person in your household (Answer c) to the
      average daily water volume used per person in
      the United States (325 L per person per day).
      What reasons can you offer  to  explain any
      differences?

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         secondary
Discussion
                                                     Source
Ask students to identify ways in which their families
couldreducetheirwaterconsumpHon.
                                                     Activity adapted with permission from:
                            Average water volumes required for typical
                         	activities	
                          Use                            Volume of Water
                                                        (in liters and gallons)
                          Tub bath
                          Shower (per min)
                          Washing machine
                           Low setting
                           High setting
                          Dish washing
                           By hand
                           By machine
                          Toilet flushing
                                                            130L (35 gal)
                                                             19 L (5 gal)

                                                             72 L (19 gal)
                                                            170L (45 gal)

                                                             40 L (10 gal)
                                                             46 L (12 gal)
                                                             11 L (3 gal)
                            Reprinted with permission from diemutry in Otc Comntimi(y. C1988, American Chemical Sodety
_
Data Table
Number of persons in family
Number of baths
Number of showers
Length of each in minutes
Number of washing machine loads
Low setting
High setting
Dish washing
Number of times by hand
Number of times by dishwasher
Number of toilet flushes
Other uses and number of each:
Cooking
Drinking
Making juice and coffee
Days
123













































                            Reprinted with permission from Chemistry m the Community. 01988, American Chemical Sodety

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       notes
-15-

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           references
The organizations below have developed or are in the process of developing science projects related to drinking water for K-12 students. This list is not
intended to be inclusive.
American Chemical Society (ACS), 1155 16th St., NW, Washington, DC 20036, (202) 872^600 [Chemistry in the Community—
Secondary 9-12].
American Water Works Association (AWWA), 6666 West Quincy Ave., Denver, CO 80235, (303) 794-7711 [Primary K-4; Middle/
Junior 5-9].
Chemical Education for Public Understanding Program (CEPUP), Lawrence Hall of Science, University of California, Berkeley,
CA 94720, (415) 642-8718 [Middle/Junior 5-8].
City of Aurora, Utilities Department, 1470 South Havana St., Aurora, CO 80012, (303) 695-7381 [Middle/Junior 5-8].
City of Seattle, 710 2nd Ave., Dexter-Horton Building, Seattle, WA 98104, (206) 684-5883 [Middle/Junior 5-8].
East Bay Municipal Utility District (EBMUD), P.O. Box 24055, Oakland, C A 94623, (415) 835-3000 [Primary K-4; Middle/Junior 5-
81.
Massachusetts Water Resources Authority, Charlestown Navy Yard, 100 First Ave., Boston, MA 02129, (617) 242-6000 [Upper
Primary 3-4; Middle/Junior 7-8; Secondary 9-12].
National Science Teachers Association (NSTA), 1742 Connecticut Ave., NW, Washington, DC 20009, (202) 328-5800 [Middle/
Junior 5-8].
National WildlifeFederation (NWF), 140016th St., NW, Washington, DC 20036, (202) 797-6800 [Primary K-4; other citizen oriented
material].
South Central Connecticut Regional Water Authority, 90 Sargent Dr., New Haven, CT 06511, (203) 624-6671 [Primary and Middle
K-6].
             s  u  p  p  I  i  e  r s
The following are some firms that provide general supplies and equipment for all areas of science teaching and also specific items for chemistry teaching.
Addison-Wesley Publishing Co., 2725 Sand Hill Rd., Menlo Park, CA 94025, [800-447-2226].
Aldrich Chemical Co., P.O. Box 355, Milwaukee, WI53201, (414) 273-3850, [800-558-9160].
Carolina Biological Supply Co., 2700 York Rd., Burlington, NC 27215, (919) 584-0381 [800-621-4769].
Central Scientific Co., 11222 Melrose Ave., Franklin Park, IL 60131-1364, (312) 451-0150.
Connecticut Valley Biological Supply Co., Inc., 82 Valley Rd., Southampton, MA 01073, (413) 527-4030 [800-628-7748].
Edmund Scientific Co., 101 East Gloucester Pike, Barrington, NJ 08007, (609) 573-6250 [800-222-0224].
Hsher Scientific Co., Educational Materials Division, 4901  West LeMoyne St., Chicago, IL 60651, (312) 378-7770 [800-621-4769].
Flinn Scientific Inc., P.O. Box231,917 West Wilson St., Batavia, IL 60510, (312) 879-6900. [The Flinn Chemical Catalog also serves as a reference
manual on chemical safety, storage, and disposal.]
Frcy Scientific Co., 905 Hickory Lane, Mansfield, OH 44905, [800-225-FREY].
Hach Chemical Co., Box 907, Ames, IA 50010. [Test kits for environmental studies.]
Lab-Aids, Inc., 249 Trade Zone Dr., Ronkonkoma, NY 11779, (516) 737-1133.
Lab Safety Supply, 3430 Palme#Dr., P.O. Box 1368, Janesville, WI 53547-1368, (608) 754-2345. [Specialize in safety equipment and supplies.]
LaMotte Chemical Products, Box 329, Chestertown, MD 21620, (301) 778-3100. [Test kits for environmental studies.]
Nalgene Labware Division, P.O. Box 367, Rochester, NY 14602. [Specialize in transparent and translucent plastic laboratory equipment.]
NASCO, 901 Janesville Ave., Ft. Atkinson, WI 53538, (414) 563-2446 [800-558-9595].
Ohaus Scale Corp., 29 Hanover Rd., Florham Park, NJ 07932, (201) 377-9000 [800-672-7722].
Sargent-WelchSdent-ncCo.,"7300 North Linder, Skokie, IL 60077, (312) 677-0600.
Science Kit and Boreal Laboratories, Inc., 777 East Park Dr., Tonawanda, NY 14150-6782, (716) 874-6020 [800-828-7777].
Wards Natural Science Establishment, Inc., 5100 West Henrietta Rd., P.O. Box 92912, Rochester, NY 14692, (716) 359-2502.
(The majority of suppliers listed above appeared in Chemistry in the Community, American Chemical Society. (Dubuque, 1 A: Kendall / Hunt
Publishing Co., 1988).]

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EPA
United Stales
Environmental Protection Agency
(4601)
Washington, DC 20460

Official Business
Penalty for Private Use
$300

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