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.
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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).
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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
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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
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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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