United States
Environmental Protection
Agency
Office of Environmental
Processess and Effects Research
Washington, DC 20460
EPA/600/9-90/027
July 1990
Acid Rain:
A Student's First Sourcebook
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This information guide was prepared under the direction of Jack Durham, Office of Environmental Processes
and Effects Research. The text was prepared by Beth Ann Kyle and Mary Deardorff of Environmental
Management Support, Inc., Silver Spring, Maryland, and Jeff Sabol of International Science and Technology
Sterling, Virginia.
Comments or questions regarding this report should be directed to:
Jack L. Durham
Office of Environmental Processes and Effects Research
U.S. Environmental Protection Agency (RD-682)
401 M Street, S.W.
Washington, D.C. 20460
Copies of the report are available from:
Office of Research and Development
Distribution Unit
U.S. Environmental Protection Agency
Cincinnati, OH 45268
Cover: Hydrologist testing water samples from a test lake (photo courtesy of International Science and
Technology, Inc.)
The information in this document has been funded wholly or in part by the United States
Environmental Protection Agency under contract number 68-03-3312 to PEER Consultants, PC. It
has been subjected to the Agency's peer and administrative review, and it has been approved for
publication as an EPA document. Mention of trade names, commercial products, or organizations is
for illustrative purposes only and does not constitute endorsement or recommendation for use.
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ACID RAIN
A Student's First Sourcebook
U.S.
JULY 1990
Office of Environmental Processes and Effects Research
Office of Research and Development
United States Environmental Protection Agency
Washington, DC 20460
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Acid Rain Sourcebook
TABLE OF CONTENTS
Purpose i
Introduction 1
Observations About Acidity 3
Defining Acid Rain 5
Effects of Acid Rain on Forests 11
Effects of Acid Rain on Water 15
Effects of Acid Rain on Human-Made Materials ... 17
Effects of Acid Rain on People 18
What Can Be Done 19
Experiments 25
Activities 47
Bibliography 51
Glossary 55
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Acid Rain Sourcebook
PURPOSE
The primary goal of the U. S. Environmental Protection
Agency (EPA) is to protect human health and the environment. One
of the ways in which EPA tries to achieve that goal is to educate the
public on matters of local and national concern. Acid rain affects
both the health of humans and our environment and is an issue
with which the EPA is actively involved. EPA provides information
on research, regulation, and other issues associated with acid rain.
Because acid rain is of national and international concern, many
other government organizations are also responsible for working on
this problem.
EPA frequently receives requests for information on acid rain
from school systems, teachers, and individuals. Some seek sugges-
tions for simple experiments to demonstrate concepts related to acid
rain science. Others want information on the latest research and
efforts to lessen the effects of acid rain. Still others want to know
how citizens can become involved in helping to reduce the potential
impact of acid rain. In response to these requests, EPA has devel-
oped this study guide. The purpose of the guide is to help students
better understand the science, citizen action, and research issues
that are part of the acid rain problem.
This book is for students in grades 4-8 and their teachers.
After reading the concepts and definitions and doing some of the
experiments and activities in the guide, we hope that they will have
a better understanding of the acid rain problem and a greater
interest in its resolution.
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Acid Rain Sourcebook
INTRODUCTION
Since the beginning of time, humans have learned to
make use of many things in nature such as fire and
electricity. From the early times through the Industrial
Revolution to the Space Age, humans have produced
inventions that use many of the earth's varied ENERGY
resources to make living easier. In many cases the energy
comes from burning FOSSIL FUELS—coal, oil, and natural
gas.
Some of the inventions that make our lives easier are
also causing POLLUTION. Pollution is the release of
harmful substances into the ENVIRONMENT. One form of
pollution is ACID RAIN. Acid rain can damage plants,
animals, soil, water, building materials, and people.
Scientists have discovered that burning fossil fuels creates
acid rain through air pollution. People burn fossil fuels
such as oil and coal to make electricity. Electricity heats
and lights buildings and runs appliances such as
televisions and video recorders. Fossil fuels power our cars,
buses, and airplanes. The air pollution created when these
fuels burn does not stay in the air forever. It can return to
the earth as acid rain. And when it does, it may weaken the
plant and animal life it contacts. Acid rain is only one form
of pollution that results from burning fossil fuels. It is of
particlar interest, however, because it can be transported
over long distances. Scientists, engineers, and researchers
Words tfiat are explained in In*
glossary, which begins on page 65,
are printed in boldface type the first
time they appear.
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Acid Rain Sourcebook
are learning how to measure the amount and effects of
pollution in the air, forests, water, and soil. They are
inventing ways to reduce the amount of pollution that
enters the environment and to prevent new damage in the
future.
Lemonade (2.2-3.0)
Milk (6.4-7.6)
Ammonia (11.0-11.5)
Apple (2.9-3.3)
I 0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Fish Affected
Buildings and Paint Affected
Trees and Plants 1
Affected I
4
fstrnnnari
1
die
Bas
/e(rnnnar\
1
Neutral
This diagram shows the pH scale. On top are some common items and their pH. A pH stronger than around 5 can harm
buildings, metals, paint, and other materials. What pH level can harm fish? How about plants? Are these levels of acidity
stronger or weaker than the level that affects materials? See the next page to learn more about pH.
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Acid Rain Sourcebook
OBSERVATIONS ABOUT ACIDITY
ACIDIC and BASIC are two extremes that describe
CHEMICALS, just like hot and cold are two extremes that
describe temperature. Mixing ACIDS and BASES can
cancel out their extreme effects, much like mixing hot and
cold water can even out the water temperature. A
substance that is neither acidic nor basic is NEUTRAL. The
pH scale measures how acidic or basic a substance is. The
pH scale ranges from 0 to 14. A pH of 7 is neutral. A pH
less than 7 is acidic. A pH greater than 7 is basic.
Pure water is neutral. But when chemicals are mixed
with water, the mixture can become either acidic or basic.
Examples of acid substances are vinegar and lemon juice.
Laundry detergents and ammonia are examples of basic
substances. Chemicals that are very basic or very acidic
are REACTIVE. These chemicals can cause severe burns.
Automobile battery acid is an acidic chemical that is
reactive. Automobile batteries contain a stronger form of
some of the same acid that is in acid rain. Household drain
cleaners often contain lye, a very ALKALINE (another way
to say basic) chemical that is reactive.
The pH Seote
The pH seals measures how bask;
or rtowaoWS&asub6lan<5& te. Her*
am some facts abwt pH.
.aeadiCiOf how bssfelhs
ih&t 7 is baste,
Each wtwie.pH value above 7
the next tower whole value, £er
sxafRpfe* pH to isl Q toes
more atkalittethatt pK 8 and
1&> toss 0<3 times, to) more
alteto than pH &,
* A solution wftfc a pH tess than ?
10 traes rnore acidic than th6
more actdc than ptt 5 and 100
lim&s {to tiffies 10 ) more addic
Experimenf s on pH
The fotl&vwng are examples of
experiman^ section beginning
Tesi fte pH
p-Test
dd) HI
then again after adding baking
Measurin aH
. Measure the pH of
common hous«hotd ftems such as
IrtdJeatpr
walh the gricfi^ou q»f acids grid
base*,
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Acid Rain Sourcebook
DEFINING ACID RAIN
Acid rain is rain that is more acidic than normal.
Acid rain is a complicated problem. Caused by air
pollution, acid rain's spread and damage involves weather,
chemistry, soil, and the life cycles of plants and animals on
the land and from acid rain in the water.
Air Pollution Creates Acid Rain
Scientists have discovered that air pollution from the
burning of fossil fuels is the major cause of acid rain.
Power plants and factories burn coal and oil. Power plants
use that coal and oil to produce the electricity we need to
heat and light our homes and to run our electric
appliances. We also burn natural gas, coal, and oil to heat
our homes. Cars, trucks, and airplanes use gasoline,
another fossil fuel.
The smoke and fumes from burning fossil fuels rise
into the ATMOSPHERE and combine with the moisture in
the air to form acid rain. The main chemicals in air
pollution that create acid rain are SULFUR DIOXIDE and
NITROGEN OXIDES. Acid rain usually forms high in the
clouds where sulfur dioxide and nitrogen oxides react with
water, oxygen, and OXIDANTS. This forms a mild solution
of SULFURIC ACID and NITRIC ACID. Sunlight increases
the rate of most of these reactions. Rainwater, snow, fog,
and other forms of PRECIPITATION containing those mild
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Acid Rain Sourcebook
Volcanoes, vegetation, and
marehland* emit sulfur and nitrogen
oxides and hydrocarbons
Power plants, businesses,
Industry, and homes emit
sulfur and nitrogen oxides
and hydrocarbons
Emissions are mixed with oxygen,
ozone, and water to form sulf uric and
nitric adds In the presence of sunlight
Dry deposition of
acids and
precursors
.Wet acid precipitation falls .
.. "to ground . ,'
Vehicles emit
nitrogen oxides and
hydrocarbons
Acidity adversely affects aquatic
and terrestrial ecosystems,
human-made materials, visibility,
and human health
Formation of Acid Rain
solutions of sulfuric and nitric acids fall to earth as acid
rain.
Acid Precipitation
Water moves through every living plant and animal,
streams, lakes, and oceans in the HYDROLOGIC CYCLE.
In that cycle, water evaporates from the land and sea into
the atmosphere. Water in the atmosphere then
CONDENSES to form clouds. Clouds release the water
back to the earth as rain, snow, or fog. When water
droplets form and fall to the earth they pick up
PARTICLES and chemicals that float in the air. Even
clean, unpolluted air has some particles such as dust or
pollen. Clean air also contains naturally occurring gases
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Acid Rain Sourcebook
such as CARBON DIOXIDE. The interaction between the
water droplets and the carbon dioxide in the atmosphere
gives rain a pH of 5.6, making even clean rain slightly
acidic. Other natural sources of acids and bases in the
atmosphere may lower or raise the pH of unpolluted rain.
However, when rain contains POLLUTANTS, especially
sulfur dioxide and nitrogen oxides, the rain water can
become very acidic.
Dry Deposition
Acid rain does not account for all of the acidity that
falls back to earth from pollutants. About half of the acidity
in the atmosphere falls back to earth through DRY
DEPOSITION as gases and dry particles. The wind blows
these acidic particles and gases onto buildings, cars,
homes, and trees. In some instances, these gases and
particles can eat away the things on which they settle. Dry
deposited gases and particles are sometimes washed from
trees and other surfaces by rainstorms. When that
happens, the RUNOFF water adds those acids to the acid
rain, making the combination more acidic than the falling
rain alone. The combination of acid rain plus dry deposited
acid is called acid deposition.
Acid Rain Is a Problem that Can Travel
The chemical reactions that change air pollution to
acid rain can take from several hours to several days. Years
ago, when smokestacks were only a few stories high,
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Acid Rain Sourcebook
pollution from smokestacks usually stayed near the ground
and settled on the land nearby. This caused unhealthy
conditions for plants and animals near those smokestacks.
To reduce this pollution, the government passed a law
permitting the construction of very tall smokestacks. At
that time, people thought that if the pollution were sent
high into the air it would no longer be a problem. Scientists
now know that this is incorrect. Sending pollution high into
the sky increases the time that the pollution stays in the
air. The longer the pollution is in the air, the greater are
the chances that the pollutants will form acid rain. In
addition, the wind can carry these pollutants for hundreds
of miles before they become joined with water droplets to
form acid rain. For that reason, acid rain can also be a
problem in areas far from the polluting smokestacks. Dry
deposition is
usually more
abundant near
the cities and
industrial
areas where
the pollutants
are released.
Eruption of the Mt. St. Helens volcano in Washington State (photo courtesy of the U.S. Fish and Wildlife Service)
8
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Acid Rain Sourcebook
Natural Acids
There are also natural sources of acids such as
volcanoes, natural geysers, and hot springs. Nature has
developed ways of recycling these acids by absorbing and
breaking them down. These natural acids contribute to
only a small portion of the acidic rainfall in the world
today. In small amounts, these acids actually help dissolve
nutrients and minerals from the soil so that trees and
other plants can use them for food. The large amounts of
acids produced by human activities overload this natural
acidity.
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Acid Rain Sourcebook
EFFECTS OF ACID RAIN ON FORESTS
Over the years, scientists, foresters, and others
have watched some forests grow more slowly without
knowing why. The trees in these forests do not grow as
quickly as usual. Leaves and needles turn brown and fall
off when they should be green and healthy.
Researchers suspect that acid rain may cause the
slower growth of these forests. But acid rain is not the
only cause of such conditions. Other air pollutants,
insects, diseases, and drought are some other causes that
harm plants. Also, some areas that receive acid rain show
a lot of damage, while other areas that receive about the
same amount of acid rain do not appear to be harmed at
all. However, after many years of collecting information on
the chemistry and biology of forests, researchers are
beginning to understand how acid rain works on the forest
soil, trees, and other plants.
ents on Acids In
Son
Oomptete Erections, for thess aftqt
fstlw experiments art! fisted to tfta
EXPERIMENTS section beginning
Determining Safl pH U&irtg a sei
, wooded arsa,
Looking *» Soil Buifertag
Measure Ike pH of aliqw^ tfeat
r, Pour an saefefic feivW
through, (ifeasure the pH agairt
first and 6«
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Acid Rain Sourcebook
in pH. Without buffering capacity, soil pH would change
rapidly. Midwestern states like Nebraska and Indiana have
soils that are well buffered. Places in the mountainous
northeast, like New York's Adirondack Mountains, have
soils that are less able to buffer acids. Since there are
many natural sources of acids in forest soils, soils in these
areas are more susceptible to effects from acid rain.
How Acid Rain Harms Trees
Acid rain does not usually kill trees directly. Instead,
it is more likely to weaken the trees by damaging their
leaves, limiting the nutrients available to them, or
poisoning them with TOXIC substances slowly released
from the soil.
Scientists believe that acidic water dissolves the
NUTRIENTS and helpful minerals in the soil and then
washes them away before the trees and other plants can
use them to grow. At the same time, the acid rain causes
the release of toxic substances such as aluminum into the
soil. These are very harmful to trees and plants, even if
contact is limited. Toxic substances also wash away in the
runoff that carries the substances into streams, rivers, and
lakes. Less of these toxic substances are released when the
rainfall is cleaner.
Even if the soil is well buffered, there can be damage
from acid rain. Forests in high mountain regions receive
additional acid from the acidic clouds and fog that often
surround them. These clouds and fog are often more acidic
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Acid Rain Sourcebook
Forest damage to which acid deposition may have been a contributing cause (photo courtesy of
the National Acid Precipitation Assessment Program).
than rainfall. When leaves are frequently bathed in this acid
fog, their protective waxy coating can wear away. The loss of
the coating damages the leaves and creates brown spots.
Leaves turn the energy in sunlight into food for growth. This
process is called PHOTOSYNTHESIS. When leaves are
damaged, they cannot produce enough food energy for the
tree to remain healthy.
Once trees are weak, they can be more easily attacked
by diseases or insects that ultimately kill them. Weakened
trees may also become injured more easily by cold weather.
Acid rain can harm other plants in the same way it
harms trees. Food crops are usually not seriously affected,
however, because farmers frequently add fertilizers to the
soil to replace nutrients washed away. They may also add
crushed limestone to the soil. Limestone is a basic material
and increases the ability of the soil to act as a buffer against
acidity.
13
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Acid Rain Sourcebook
EFFECTS OF ACID RAIN ON WATER
The effects of acid rain are most clearly seen in the
AQUATIC, or water, environments, such as streams, lakes,
and marshes. Acid rain flows to streams, lakes, and
marshes after falling on forests, fields, buildings, and
roads. Acid rain also falls directly on aquatic HABITATS.
pH6.5
pH6.0
pH5.5
pH 5.0
pH4.5
pH4.0
TROUT
BASS
PERCH
FROGS
SALAMANDERS
CLAMS
CRAYFISH
SNAILS
MAYFLY
This chart shows that not all fish, shellfish, or their food insects can tolerate the same amount of acid. Fish like trout, bass, and perch are
affected at different pH levels. Which type of fish are the most sensitive to acid? Generally, the young of most species are more sensitive
than adults. Frogs may tolerate relatively high levels of acidity, but if they eat insects like the mayfly, they may be affected because part
of their food supply may disappear.
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Acid Rain Sourcebook
Most lakes and streams have a pH between 6 and 8.
However, some lakes are naturally acidic even without the
effects of acid rain. Lakes and streams become acidic (pH
value goes down) when the water itself and its surrounding
soil cannot buffer the acid rain enough to neutralize it. In
areas like the northeastern United States where soil buf-
fering is poor, some lakes now have a pH value of less than
5. One of the most acidic lakes reported is Little Echo Pond
in Franklin, New York. Little Echo Pond has a pH of 4.2.
Lakes and streams in the western United States are
usually not acidic. Because of differences in emissions and
wind patterns, levels of acid deposition are generally lower
in the western United States than in the eastern United
States.
As lakes and streams become more acidic, the
numbers and types of fish and other aquatic plants and
animals that live in these waters decrease. Some types of
plants and animals are able to tolerate acidic waters.
Others, however, are acid-sensitive and will be lost as the
pH declines. Some acid lakes have no fish. At pH 5, most
fish eggs cannot hatch. At lower pH levels, some adult fish
die. Toxic substances like aluminum that wash into the
water from the soil may also kill fish.
Together, biological organisms and the environment
in which they live are called an ECOSYSTEM. The plants
and animals living within an ecosystem are highly inter-
dependent. For example, fish eat other fish and also other
plants and animals that live in the lake or stream. If acid
rain causes the loss of acid-sensitive plants and animals,
then fish that rely on these organisms for food may also be
affected.
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Acid Rain Sourcebook
EFFECTS OF ACID RAIN ON HUMAN-
MADE MATERIALS
Acid rain eats away at stone, metal, paint—almost
any material exposed to the weather for a long period of
time. Human-made materials gradually deteriorate even
when exposed to unpolluted rain, but acid rain accelerates
the process. Acid rain can cause marble statues carved
long ago to lose their features. Acid rain has the same
effect on buildings and monuments. Repairing acid rain
damage to houses, buildings, and monuments can cost
billions of
dollars.
Ancient
monuments
and buildings,
such as the
Parthenon in
Greece, can
never be
replaced.
Example of acid deposition effects on a monument (photo courtesy of
the National Park Service).
Acid Rain, EKects on Marble
{Chalk)
com;pounjtoecurring in rocks, ;
... and in animal bones, shells, and ::'*!
teeth. Marble and limestone are : • •!
Aiding mat$rfateverntgrtf< The next day,,
see if you cfin tell vyhtoh.jwece of
cfialk is rfiore wsrn away.
1;, metate.Cortiplete instructions for;
^ th|s and o%ersxperttnents can .
. flitnted before 1983;.
:;: Place Bie other. : peiiny Jrt a cup :
v.pf yinegajr or (emfiin ju fw. After 5
:daj%, observe ttieeffeetaof the •
different liquids i>n each.perir»y,.. ;:
Observe again in two weeks,
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Acid Rain Sourcebook
EFFECTS OF ACID RAIN ON PEOPLE
Acid rain looks, feels, and tastes just like clean rain.
The harm to people from acid rain is not direct. Walking in
acid rain, or even swimming in an acid lake, is no more
dangerous than walking or swimming in clean water. The
air pollution that causes acid rain is more damaging to
human health. Sulfur dioxide and nitrogen oxides, the
major sources of acid rain, can irritate or even damage our
lungs.
The pollutants that cause acid rain can also reduce
visibility—limiting how far into the distance we can see.
The primary pollutants associated with acid rain and
poor visibility are human-made sulfur dioxide emissions.
These emissions form small sulfate particles, or aerosols, in
the atmosphere. These aerosols reduce visibility by
scattering light. Sulfate aerosols are the main cause of poor
visibility in the eastern United States.
Nitrogen oxide emissions are also associated with
the acid rain problem. They, too, can form aerosols in the
atmosphere that significantly reduce visibility. Nitrate
aerosols are often the main cause for poor visibility in the
western United States where sulfur dioxide emissions and
humidity are lower than in the east.
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Acid Rain Sourcebook
WHAT CAN BE DONE
To solve the acid rain problem, people need to
understand how acid rain causes damage to the
environment and what can be done to help stop acid rain.
More information on the problem will help leaders make
better decisions about how to control air pollution—the
cause of acid rain.
Scientific Research
Experts from the United States Environmental
Protection Agency (EPA) have taken samples of pollution
and acidity from thousands of streams and lakes in the
United States. From these samples, they determine the
number of streams and lakes which are now acidic and
Scientists are collecting samples of plants and animals (photo courtesy of
the U.S. Fish and Wildlife Service).
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Acid Rain Sourcebook
which are in danger of becoming acidic. EPA and other
scientists are also studying the effects of acid rain on fish,
plants, humans, and materials such as marble, brick,
cement, and metal.
Until we reduce air pollution, acid rain will continue
to be a problem. Activities to resolve this problem include
cleaning up the smokestacks and exhaust pipes that pour
pollutants into the air, finding alternative sources of
energy, repairing the damage already done by acid rain,
and conserving our resources.
Cleaning up Smokestacks and Exhaust Pipes
Right now, burning FOSSIL FUELS is one of the
most inexpensive ways to produce electricity for the daily
activities of modern life and to power cars, buses, and
airplanes. In the United States, sulfur in coal makes up the
greatest part of the sulfur dioxide that becomes acid rain.
When coal is burned to make electricity or heat, the sulfur
goes up the smokestacks and into the atmosphere to
become air pollution.
There are several ways to reduce the amount of
sulfur entering the air. One way is to wash the sulfur out of
the coal before it is burned. Another is to wash the sulfur
out of the smoke before it goes up the smokestacks.
SCRUBBERS remove sulfur from the smoke by spraying a
mixture of water and powdered limestone into the
smokestack. This mixture traps the sulfur before it can
escape into the air above.
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Acid Rain Sourcebook
Scientists and engineers are also discovering new
ways to burn fossil fuels that produce much lower amounts
of pollution.
Nitrogen oxides from burning coal and from vehicles
also contribute to acid rain. Vehicles give off nitrogen
oxides and other pollutants in their exhaust fumes. Devices
such as CATALYTIC CONVERTERS reduce the pollution
from those exhaust fumes. All new cars sold in the United
States are required to have catalytic converters.
Alternative Ways of Producing Energy
There are other sources of energy besides fossil fuels.
These include HYDROELECTRIC POWER and NUCLEAR
POWER. Dams use the power of water to turn TURBINES
and make electricity. People have been using this form of
energy for most of this century. Nuclear power plants make
electricity from the energy released by splitting atoms. A
small amount of nuclear fuel can make a very large
amount of electricity.
There are problems with using hydroelectric and
nuclear power. Hydroelectric plants require a constant
source of water. Because rainfall is not always predictable,
hydroelectric plants are not as reliable as those using coal
or oil. Hydroelectric plants can also harm the environment.
Thousands of acres of land often have to be flooded to
create a RESERVOIR, a holding place for the great
amounts of water needed to power these plants. Sometimes
the land that would be flooded is home to rare types of
2?
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Acid Rain Sourcebook
plants or animals. Nuclear power plants produce electricity
cheaply. But the nuclear waste they leave remains
dangerous for thousands of years.
Scientists are looking at other energy sources, such
as windmills and SOLAR ENERGY, using the power of the
sun itself. In several states, there are modern windmills
like airplane propellers that make electricity from the wind.
In other places, wind power pumps water from the ground.
In Arizona and New Mexico, solar energy is at work making
electric power. Each of these sources has drawbacks as
well. Windmills and solar panels are reliable only where it
is windy or sunny most of the time.
All sources of energy have benefits and limitations,
including the cost of producing the energy. All of these
factors must be weighed when deciding which energy
source to use.
Restoring a Damaged Environment
It can take years for an acidic lake or stream to
recover naturally, even if the acid rain stops. People have
brought some lakes and streams back to neutral or basic
conditions more quickly than nature could alone. They
have added powdered limestone (a natural base) to the
water in a process called LIMING. The people of Norway
and Sweden have successfully restored hundreds of lakes
and streams with liming. Few lakes and streams have been
limed in the United States.
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Acid Rain Sourcebook
Liming is expensive and the effects are only
temporary. As long as acid rain continues to fall, limestone
must be reapplied or the water will become acidic again.
Liming may be the only way to make sure that life in acid
lakes or streams survives until the amount of acid rain
falling on the surrounding land can be reduced.
Conserving Resources
It may seem like there is not much that individuals
can do to stop acid rain. However, environmental
problems—including acid rain—are caused by the
combined actions of individual people. Individuals can take
part in solving those problems as well. One of the first
Scientists are adding an alkaline material to a lake to neutralize acids in the water (photo courtesy of
International Science and Technology, Inc.)-
23
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Acid Rain Sourcebook
steps is to assume responsibility for the problem by finding
out what can be done.
Each person who turns off lights when no one is using
them and uses energy-saving appliances reduces the amount
of electricity a power plant needs to produce. When less
power needs to be produced, pollution from power plants
decreases. Car-pooling, using public transportation, and
walking reduce the pollutants that come from vehicles. The
sum total of all of these individual actions can be very great
indeed.
The more informed people are about acid rain and
other environmental problems, the more they can do to make
the earth a cleaner, healthier place. Books, pamphlets, films,
and other resource materials are listed in the Bibliography of
this guide, beginning on page 51.
24
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Acid Rain Sourcebook
EXPERIMENTS
For most of the following experiments, you will need
a pH indicator, such as wide-range litmus or pH paper, a
garden soil pH testing kit, or a pH indicator that you can
make yourself (see "Making a Natural pH Indicator", Ex-
periment #3). These pH indicators contain a chemical that
changes color when it comes in contact with acids or
bases. For example, litmus and pH paper turn red in
strong acids and blue in strong bases. Because only a few
pH indicators measure pH over a wide range of pH values,
you will need to find out the pH range of the indicator you
use. Typically, the color chart provided with each pH indi-
cator kit will show the pH range of that indicator. Color pH
indicators provide only an approximate measure of the pH,
or the strength of the acid or base. They are not as accu-
rate as the expensive instruments scientists use to meas-
ure pH, but they are adequate for the following experi-
ments.
List of Experiments
1, Measuring pH
2, Determining pH of Common
3. MaklogaMaturaipHindicator
4 Measuring tfie pHo* NatoralWatef
5. Measuring Soil pH
>$
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Acid Rain Sourcebook
Experiment Supplies
For the names of supply companias,
you can consult the yeJJow pages of
your telephone directory under a
heading such as "laboratory
Equipment and supplies.' If your local
directory does not have such a
from a larger city, telephone
'&w$8fc» are available ?ft nwny
Measuring Liquids with a Garden Soil pH Test Kit
Soil pH test kits are designed to measure the pH of
soil, but they may also be used to measure the pH of liq-
uids, such as water and water mixtures. Most of these kits
contain a test solution (liquid pH indicator), color chart,
and clear plastic test container, such as a test tube.
To measure pH, pour 1 /4 teaspoon of the mixture you
want to test into the test container, and add 1 /4 teaspoon
of the test solution provided in the kit. Cover the container
and shake once or twice to mix, or stir if necessary.
Compare with the color chart provided with the kit and
write down the result.
Tips
Except for wide-range pH test paper, all the materials
called for in these experiments, including distilled water
and borax, can be obtained at grocery stores or from
local lawn and garden stores or nurseries.
Wide-range pH test paper is inexpensive, but not easily
obtained. A school science laboratory will probably have
it or can order it, or you may order it through a biologi-
cal supply company. Litmus pH paper is usually in-
cluded in chemical sets sold at toy stores for children
over 8 years old.
Inexpensive garden soil pH testing kits are available at
most lawn and garden stores or nurseries. These testing
kits usually contain a pH indicator solution that covers
a range of at least pH 4 to 10, which is wide enough for
26
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Acid Rain Sourcebook
most of the following experiments.
• You may substitute baking soda for household ammonia
in the experiments. If you do, be sure to stir well
because baking soda does not dissolve easily in water
unless heated. The pH of undissolved baking soda will
not be the same as dissolved baking soda.
» You may substitute fresh-squeezed lemon juice for white
vinegar. Lemon juice is slightly more acidic than the
vinegar sold in grocery stores. White vinegar is preferred
over cider vinegar or lemon juice because it is colorless
and relatively free of impurities.
• Use clean, dry containers and utensils.
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Acid Rain Sourcebook
Safety in the Laboratory
A science or chemistry laboratory can and should be a safe
place to perform experiments. Accidents can be prevented if
you think about what you are doing at all times, use good
judgement, observe safety rules, and follow directions.
Each experiment will include comments to alert you to
probable hazards, including how to protect yourself and
others against injury.
• Eye protection (goggles or safety glasses) must be worn
when working on experiments. Make a habit of putting
them on before the experiment begins and keeping them
on until all clean-up is finished.
• Do not eat, drink, or smoke while in the laboratory.
• Do not taste any chemical.
• Long-sleeved shirts and leather-topped shoes must be
worn at all times.
• Long hair must be tied back, so it will not fall into
chemicals or flames.
• Do not work alone; work with an adult.
• Never perform any unauthorized experiment.
• All glassware must be washed and cleaned. Wipe all
counter surfaces and hands with soap and water.
• All experiments that produce or use chemicals that
release poisonous, harmful, or objectionable fumes or
vapors must be done in a well-ventilated area.
• Never point the open end of a test tube at yourself or
another person.
• If you want to smell a substance, do not hold it directly
to your nose. Instead, hold the container a few
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Acid Rain Sourcebook
centimeters away and use your hand to fan vapors
toward you.
• When diluting acids, always add the acid to the water;
never water to acid. Add the acid slowly.
• Flush with large quantities of water when disposing of
liquid chemicals or solutions in the sink.
• If you spill any acid or base material on you, wash the
exposed area with large amounts of cold water. If skin
becomes irritated, see a physician.
Recording Observations
Writing your observations on these experiments will help
you to keep better track of the progress of the experiment.
Written data are not forgotten. Record keeping can be very
simple and still be a help. These hints can help you organ-
ize and record your thoughts.
• Use a bound notebook so that pages are not lost.
• Write complete sentences for all written entries.
• Use drawings as needed.
• Date each entry (even drawings).
• Use the title of the experiment as your first entry.
• When your observation entries have been completed,
write your answers to the questions that follow each ex-
periment.
• Write your own thoughts about the experiment as the
conclusion.
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Acid Rain Sourcebook
Materials:
• pH paper and color chart (pf-J
range 3 to 12) or garden soit
grocery stores and drag stores)
white vinegar
household amm onia {or baking
soda) :
3 small, clear cwps or glasses
3 stirrtng spoons
measuring cups and epoons
(t/2cup, 1/4 and 1/2 teaspoon)
EXPERIMENTS!
Measuring pH
This experiment will illustrate how to measure the approxi-
mate pH of chemicals in water using a pH indicator. A pH
indicator is a chemical that changes color when it comes in
contact with acids or bases.
Instructions:
1. Rinse each cup with distilled water, shake out excess
water, and label one cup vinegar, the second cup ammo-
nia, and the third cup water.
2. Pour 1/2 cup distilled water into each of the 3 cups.
3. Add 1/2 teaspoon white vinegar to the vinegar cup and
stir with a clean spoon.
4. Add 1 /2 teaspoon ammonia to the ammonia cup and
stir with a clean spoon.
5. Do not add anything to the water cup.
6. Dip an unused, clean strip of pH paper in the vinegar
cup for about 2 seconds and immediately compare with
the color chart. Write down the approximate pH value
and set the cup aside. (If using a garden soil pH tester
kit, pour 1/4 teaspoon of the contents of the vinegar
cup into the test container, and add 1/4 teaspoon of the
test solution.) Cover the test tube and shake once or
twice to mix, or stir if necessary. Compare with the color
chart provided in the kit, and record the result.
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Acid Rain Sourcebook
7. Dip an unused, clean strip of pH paper in the ammonia
cup for about 2 seconds and immediately compare with
the color chart. Write down the approximate pH value
and set the cup aside. (If using a garden soil pH tester
kit, repeat the same process in step 6 using the con-
tents of the ammonia cup instead of the vinegar cup.)
8. Dip an unused, clean strip of pH paper into the water
cup for about 2 seconds and immediately compare with
the color chart. Write down the approximate pH value.
(If using a garden soil pH tester kit, repeat the same
process above using the contents of the water cup in-
stead of the ammonia cup.)
Questions:
1,. Is vinegar an acid or a base.?-:
(Vinegar is an acid, and in this
experiment it will display a pH of
about 4. Vinegar at pH 4 turns pH
paper yeflQW andrna$ lo&er pH;:;
indicatorsred.)
Z, Is ammonia an aolef or a bass?
(Ammonia is a base and in this
experiment it will display a pH of
about 10. Bases turn mostpH
indicatorabiue.)
3. Were you surprised to find that the
distilled water did not have a
neutral f>H?
(Pure distilled wafer would have
fc^ec" neutral, but parediistille:d
water fs not easily obtained
because carbon dioxide m foe air
around us mixes, or dissolves, in
the water, fliaking K somewhat
acidic. The pH of distilled water is
between 5.6 and 7. To neutralize
distilled water, add about 1/8 tea-
$ppon baking $0da, Pr a dreg of
pH of tie water wifli a ptt
inoloator,. I
repeat the process until pH ? is
reached. Should you accidentally
add too .rnueh.baklng soda or ani-
monia, either start over or add a.
drop or two of vinegar, stir, and
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Acid Rain Sourcebook
Materials:
» pH pspersnd cgfor chart fangs
pH £jo 12J or garden soil ptt
: testing Mt
» & fresh whole frutte (lemon,
time, orange, of melon)
• 3 beverages (cola, carbonated
••••'••• non-cote, milk) •••-. . 7.
•f. ••.• 1/8 teaspoon borax >••' ;.'"••••
•j; distilled.water|y""' .. :.;.
'• .. ftieasurirtgspoons(t/4and:|.... •
"'••' Wteaspoons). . .:.'•" :
• 4 srnall, clear
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Acid Rain Sourcebook
5. Pour each liquid into an appropriately labeled cup.
6. Dip an unused strip of pH paper into the cola, compare
with the color chart, and record the result. Repeat the
same process for the remaining beverages. Be sure to
use a clean, unused strip of pH paper for each one. (If
using a garden soil pH tester kit, pour 1/4 teaspoon of
cola into the test container, and add 1/4 teaspoon of the
test solution. Tightly press your finger over the top of
the test container and shake once or twice to mix, or stir
if necessary. Compare with the color chart provided in
the kit, and record the result.)
7. Add 1/8 teaspoon borax to 1/4 cup distilled water and
stir for about 2 minutes. Dip an unused strip of pH
paper in the borax mixture, compare with the color
chart, and record the result. (If using a garden soil pH
tester kit, pour 1/4 teaspoon of the borax/water mix-
ture into the test container, and add 1/4 teaspoon of
the test solution. Tightly press your finger over the top
of the test container and gently shake, or stir if neces-
sary. Compare with the color chart provided in the kit,
and record the result.)
Questions:
t. Are temons, limes, and oranges
acids or bases?
{These fruits all contain acids
and taste sour. Lemons and
: Jfnrie> have pM values near %
acfd.ic.tHah temorts ahd ttfnes,
but your pH indicator may not Jw
. difference*) ..... , ...... : ..... :. '
£.... Are colas and non-colas acids
':•• (TheV aw boih acidic, primarily. •
. . became tf^y contain carbon . :
dlpidcte to make them fizz, and
. carbon dioxide and water
. .. produce carbonic acid, The pH ;
: of these ijeverages varies with
. the amount of carbon dioxide
. and other ingredients in them ..-
but Is usually below 4.)
3.. Was the ffliik acidic or basic?
. . Milk can be slightly basic or
,$ttghdy acidic, depending on its
.age and how it was processed
: at the dairy,
"4* :Wastt?eborax/waterm!xture I
, acidic or.basic?
...... {Borax contains a strong base . .
: . • and wi turn most pH indicators
! blue, the appro ximatepH of the
. feoraxAwater mixture is 11. its
: ...... . ; alkaline properties make it an. . . ;. .
..-is. why., gome people us* ft to
;'•', wash clothes,). : ;-
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Acid Rain Sourcebook
Materials:
* stainless steal or enamel pan or
: microwave casserole dtetv
» 1 quart water
stove, microwave, or hotptate
• white vfnegar
• ammonia or baking soda
» dear, non-cola beverage
* 3 glass cy p$ (prdfer ab) y ofear }
* $ dean teaspoons for stirring
* measudngenp(J/4cwp)
* notebook and pertcif
EXPERIMENT #3
Making a Natural pH Indicator
In this experiment you will make your own pH indicator
from red cabbage. Red cabbage contains a chemical that
turns from its natural deep purple color to red in acids and
blue in bases. Litmus paper, another natural pH indicator,
also turns red in acids and blue in bases. The red cabbage
pH indicator can be obtained by boiling the cabbage.
Instructions:
1. Boil cabbage in a covered pan for 30 minutes or micro-
wave for 10 minutes. (Don't let water boil away.)
2. Let cool before removing the cabbage.
3. Pour about 1/4 cup of cabbage juice into each cup.
4. Add 1/2 teaspoon ammonia or baking soda to one cup
and stir with a clean spoon.
5. Add 1/2 teaspoon vinegar to second cup, stir with a
clean spoon.
6. Add about 1 teaspoon clear non-cola to the last cup and
stir with a clean spoon.
7. After answering the first two questions on the next page,
pour the contents of the vinegar cup into the ammonia
cup.
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Acid Rain Sourcebook
Related Experiment: Neutralizing Acids or Bases Using a
Garden Soil pH Tester Kit
Pour 1/4 teaspoon of the contents of the vinegar cup
into the test container, and add 1/4 teaspoon of the test
solution. Seal the top of the test container with your fin-
ger, shake once or twice, or stir if necessary, and com-
pare with the color chart. Then pour about 1/4 tea-
spoon of the contents of the ammonia cup into the test
container. Mix it and compare with the color chart.
What happens to the pH? What would happen if you
added more of the ammonia mixture? (For answers: see
questions 3 and 4.)
Questions:
1. What color change took piace
. when you added vinegar to the. ;
.:• :.• cabbage juice? Why? , '
••:, ;i (The vinegar and cabbage juice .
5 . mixtures should change from
: deep purple to red, indicating
that vinegar is an acjd.)
2. Ofd the ammonia torn Sue
cabbage juice pH indicator red or
•;•• blue? Why? •••••
; . (The ammonia and cabbage ;
juice mixture should change from
deep purple to blue, because
ammonia, like baKing soda, is a .
: base, which reacts ebemtaally .
with the pH indicator, turning it \
blue.) '.;
3, What happens to the coior tf you
'< pour the contents of the vinegar
: ; . cup into the,ammonla cup?
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Acid Rain Sourcebook
Materials:
:.• ..'"•". f>H paper and color chart grange
• : ::. ijrgaKfen sol pH testing kit
••» ,:'""' )
EXPERIMENT #4
Measuring the pH of Natural Water
In this experiment you will measure the pH of natural
water located near your home or school.
Instructions:
1. Locate a stream, river, lake, or pond. Go with an adult.
2. Scoop some of the surface water into a cup.
3. Measure the pH of the water using either pH paper or a
garden soil pH testing kit (procedures described in the
introduction to the experiments section) and record the
result.
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Acid Rain Sourcebook
EXPERIMENT #5
Measuring Soil pH
In this experiment you will collect soil and measure its
pH. Soil pH is one of several important conditions that
affect the health of plants and animals. In addition, you
will also be asked to survey the plants and animals that
live in the area where you collected the soil. Area surveys
provide information about how well plants and animals can
live under different conditions.
For this experiment, you will need an inexpensive gar-
den soil pH test kit, which may be obtained from lawn and
garden stores or nurseries.
Instructions:
1. Pick two or three different soil locations, such as a gar-
den, wooded area, city park, or meadow. Ask an adult to
go with you.
2. At each location, observe the plants and animals living
in or rooted on these soils, especially those that are in
greatest numbers. Write down as much as you can
about what you find. Dig down about 2 inches, scoop
out 2 cups of soil, and seal it in a plastic bag for later
use. Label each plastic bag. Be sure to clean your dig-
ging tool after collecting soil samples at each location.
3. Measure the pH of each soil sample following the direc-
Moterials:
gard
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Acid Rain Sourcebook
Questions:
' 1 < Were there any fatg
differences between the plant
artdarttmal life at each
location? (Some types
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Acid Rain Sourcebook
EXPERIMENT #6
Soil Buffering
Soil sometimes contains substances, like limestone, that
buffer acids or bases. Some salts in soil may also act as
buffers. In this experiment you will find out if soil from
your lawn, garden, or school can buffer acids. You will
observe the pH change of an acid mixture poured over soil
in a filter. If the water collected from the filter is less acidic
than the original mixture, then the soil is buffering some of
the acid. If it does not change, then the soil may not be
capable of buffering acids. Since the buffering capability of
soils differs, you may want to do this experiment with
several different soil types including those collected for the
"Soil pH" experiment.
Instructions:
Materials:
pHj»pwancf color oharMpH
or garden sott ptf test kit
about 2 cups 01 soil from a
garden, wooded areajawn.or
(school yard
distilled water
stirring spoon
large funnet
papercup
notebook and pencit
1. Pour 1 teaspoon of vinegar into 2 cups of distilled water,
stir well, and check the pH with either pH paper or a
garden soil pH testing kit (procedures described in the
introduction to the experiments section). The pH of the
vinegar/water mixture should be about 4. If it is below
that, add a sprinkle of baking soda, stir well, and re-
check the pH; but if it is above pH 4, add a drop or two
of vinegar and again recheck the pH.
2. Put 1 coffee filter into the funnel, and fill the filter with
soil from one location. Do not pack the soil down.
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Acid Rain Sourcebook
Questions:
•i; :, Did the pttof the collected
"... water stay the same as the '; "i •';
original mixture, increase, or :
decrease? ..•"•" ,-:/ .. •••" y.:
..:.;.' (If tht pH stayed Jhg .same'; jfj^'
,;:"' soil did not puffer the acid, .>•
/r: Each pH value abbve 4 : . .. i
indicates that the soil burred :*;
increasing amountsKjf the acid
Even soil capable of buffering
acids can be overpowered 8
enough add is added. As more
acid is added to the soil the :
and the water from the fitter •'" .. ,
becomes more acidic,) ,
2. What can you add to the sol) to
increase its buffering
capability?
(Limestone can be added, but
the limestone to work into the
soil.) '• :• •" '.•••".•/
3. Hold the filter over a paper cup and slowly pour the
vinegar/water mixture over the soil until some water
collects in the paper cup (the filter may clog quickly, but
you need only a small amount of water).
4. Check the pH of the collected water using either pH
paper or a garden soil pH testing kit and record the
results (procedures described in the introduction to the
experiments section).
5. Repeat the experiment with other soil samples, using a
new coffee filter for each sample.
40
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Acid Rain Sourcebook
Materials:
EXPERIMENT #7
Observing Influence of Acid Rain on Plant Growth
Acid rain most often damages plants by washing away
nutrients and by poisoning the plants with toxic metals. It
can, however, have direct effects on plants as well. In this
experiment you will observe one of the direct effects of acid
water on plant growth. The experiment will take about 2
weeks.
white vinegar
measwringcupe
stirring spoon
2cuttingsofaphilodendron
pfant(t teaf artcf small amount
of stem)
2 cuttings of a begonia or
coteus plant (1 leaf and small
Instructions:
1. Pour 1 teaspoon of vinegar into 2 cups of distilled
water, stir well, and check the pH with either pH paper
or a garden soil pH testing kit (procedures described in
the introduction to the experiments section). The pH of
the vinegar/water mixture should be about 4. If it is
below pH 4, add a sprinkle of baking soda, or a drop of
ammonia, stir well, and recheck the pH. If it is above
pH 4, add a drop or two of vinegar and again recheck
thepH.
2. Measure the pH of the distilled water using either pH
paper or a garden soil pH testing kit. If the pH is below
7, add about 1/8 teaspoon baking soda, or a drop of
ammonia, stir well, and check the pH of the water with
the pH indicator. If the water is still acidic, repeat the
41
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Acid Rain Sourcebook
Question:
fastest root growth, those in
distilled water or those In ackf :
water?
water should grow tester than
plants grown in acid waser<
Acid water, tike add rain, can
directly damage plants and
slow or stop new growth.^ :
process until pH 7 is reached. Should you accidentally
add too much baking soda or ammonia, either start
over again or add a drop or two of vinegar, stir, and
recheck the pH.
3. Put one of the following labels on each cup or jar:
water philodendron
acid philodendron
water begonia (or coleus)
acid begonia (or coleus)
4. Pour about a cup of distilled water into the water-
philodendron and water-begonia cups.
5. Pour about a cup of the vinegar/water mixture into the
acid-philodendron and acid-begonia cups.
6. Put one philodendron cutting into each philodendron-
labeled cup, covering the stem and part of the leaf with
the liquid.
7. Put one begonia cutting into each begonia-labeled cup,
covering the stem and part of the leaf with the liquid.
8. Set the cups where they are not likely to be spilled and
where they will receive some daylight.
9. About every 2 days, check to be sure that the plant
cuttings are still in the water or vinegar/water. You
may need to add more liquid if the cups become dry.
10. After 1 week, compare the new root growth of each
plant in distilled water with the new root growth of its
corresponding plant in acid water. Record the results.
11. After 2 weeks, again observe the plant cuttings for new
root growth, and record the results.
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Acid Rain Sourcebook
EXPERIMENT #8
Observing Buffers in Lakes, Ponds, and Streams
In this experiment you will observe the effects of lime-
stone on the acidity of water. Some areas of the nation
have a lot of limestone in lake bottoms and in soil, which
helps neutralize the effects of acid rain. Crushed limestone
is sometimes added to lakes, ponds, and other aquatic
areas to help neutralize the effects of acid rain, thus pre-
serving important aquatic systems until the source of acid
rain can be reduced. Crushed limestone is easily obtained
from local lawn and garden stores or nurseries.
Materials:
pH paper and .color chart
(range pH 2 to 7)
or garden soil pH testing kit
white vinegar
distilled water
measuring cup and spoon
£ stirring *paons
112 cup crushed hydrated
limestone or spray limestone
£ cereal *x>wt& (about 2 ei»p
size)
plastic.wrap :.;• . .•
notebook and. pencil .'"' • ','
Instructions:
1. Label one bowl vinegar; the other one vinegar plus lime-
stone.
2. Pour 1/4 cup crushed limestone into one bowl.
3. Pour 1 teaspoon of vinegar into 2 cups of distilled water,
stir well, and check the pH with either pH paper or a
garden soil pH testing kit (procedures described in the
introduction to the experiments section). The pH of the
vinegar/water mixture should be about 4. If it is below
pH 4, add a sprinkle of baking soda, stir well, and re-
check the pH; but if it is above pH 4, add a drop or two
of vinegar and again recheck the pH.
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Acid Rain Sourcebook
Questions:
' 1.."' Did the pH of the vinegar/water
. mixture over &» limestone1 '"•>.;;;;'
• - become rnore or less acidic , •
during the 6-day period? viyhy?;;
",. (The water mixtur e should 'havex
: bewme less aeitfc, changing/
. ... from about j>H 4 to $$ rrtgch'l*;.
pHe.ctependinganthewatei' ;
content ol the. limestone yow: -x.
. •••used! "v1 . ' :''"":.;:;.:.:
2. Does crushed limestone buffer
Sieaeld? ••:,., •••x
(Yea, by neutralizing tt.) •./••'• .
9. Did the pH of the vinegar/water
mixture in thia otttarbowt
(without limestone) change: .•;:
dgring the 6-day period? : ,
(The pH of the bowl without. ;...
limestone should not have
changed.) ;...-.-
4. Pour about 1 cup of the vinegar/water mixture over the
limestone in the cereal bowl and stir with a clean, dry
spoon.
5. Pour the remaining vinegar/water mixture into the other
cereal bowl.
6. Check the pH of the vinegar/water mixture over the
limestone and record it.
7. Cover each bowl with plastic wrap to prevent evapora-
tion.
8. Every day for 6 days, stir the contents of each bowl with
a clean, dry spoon and about 4 or more hours later
(after the limestone has settled), test the pH of the water
mixture in each bowl and record the result.
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Acid Rain Sourcebook
EXPERIMENT #9
Looking at Acid Effects on Metals
When acids and metals come in contact with each other,
the metal is gradually dissolved away in a chemical reac-
tion. In this experiment you will observe this reaction for
yourself, but you will need patience. The chemical effect of
acids on metals may take at least five days for the human
eye to see, even though the reaction starts as soon as the
acid contacts the metal.
Instructions:
Materials:
$>n papsr and color chart {pH
range 2 to 7)
or garden soil pH testing kit
; 2 small, clear glasses
{nownefaf}
2 clean copper parirttes (use
permiesfninted
squeezed lemon juice
distilled water
plastfowrap
1. Label one glass water and the other vinegar or lemon
juice depending on which acid you use.
2. Place one penny in each glass. Be sure to use pennies
minted before 1983 because pennies minted after that
time have a different chemical composition.
3. Barely cover one of the pennies with either vinegar or
lemon juice.
4. Dip a strip of pH paper into the vinegar, or lemon juice,
for about 2 seconds, compare with the color chart, and
record the result. Or use a garden soil pH test kit (pro-
cedures described in the introduction to the experi-
ments section).
5. Add enough distilled water to the glass labeled water to
barely cover the other penny.
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Acid Rain Sourcebook
Questions:
:;' 1,.; '•:f: What change, if any, took pj$ce
• in the water glass after 5 days?
J ;.;;(There should be n0ehang&4
%.• Vi^at change, .if any, *?£>k
.-;;&.. place5i flievinegar
;•!•!> •
':•'• ,:.:;:! (The liquid should be bluish-
jgreen, The bluish-green
H substance irithe vinegar, or
•:;."" -"lemon juice, comes from the
: copper in )he penny Jt is a
/'" ..byproduct of the chemical
: ,,, reaction in which the acid lit :
..../""the vinegar, Drlerppnjuiqe,-
; ytey gradually eats away ^e
3> ..;: Wflienyou rinsed off the
. pennies, where you surprised
.v • • titet they both looked abool the
same as they did at the
• •'•" .. beginning of the experiment
• (assuming ydu used clean
,.:..• pennies)?
"; \Cnie chemical rpaction
ooppef penny is $a slow that
,yqy cannot see any difference
; in the shape 6l ttie metal injyst
:: 5 days^ at least notwith your;
eye alone. You may see some
: .changes after about 2 weeks. ..
aspeciatty at the edge of the
6. Dip a strip of pH paper into the distilled water for
about 2 seconds and compare with the color chart. Or
use a garden soil pH test kit (procedures described in
the introduction to the experiments section). If the pH
is below 6, add a tiny amount (less than 1/8 teaspoon)
of baking soda, or a drop of ammonia, and recheck the
pH. Repeat this process until the pH is between 6 and
7. Record the pH of the water.
7. Seal the top of each glass with plastic wrap to prevent
evaporation.
8. Place in a safe, dry place for about 5 days.
9. After about 5 days, observe the changes that occurred
in each glass.
10. At the end of the experiment, wash off the pennies
with water, and pour the contents of the glasses down
the sink (do not drink).
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Acid Rain Sourcebook
ACTIVITIES
• Classroom: Collect acid rain and air pollution cartoons
from newspapers and magazines. Display and discuss
them.
• Classroom: Imagine that you are all scientists. Think
about a research project to investigate some aspect of acid
rain—how it forms, the damage it does, etc. Write your
ideas on the board. Discuss the questions you would ask
and the steps you would take to do the research. If pos-
sible, invite a local research scientist to the classroom to
review your project and comment on it.
• Small groups or individuals: Write, produce, and direct a
special segment for a T.V. "weather special" on the effect of
weather patterns on the travel of acid rain over large dis-
tances. Contact the weather bureau or a local television
station's weather department to ask about the wind pat-
terns in your area.
• Class Trip: Visit a nearby science center or museum of
science. Request information on educational programs for
acid rain. Look for exhibits that relate to the causes and
effects of acid rain and how acid rain travels (weather).
Note: If there is no such museum nearby, write to the near-
est one and request information on educational programs
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or their exhibits that deal with acid rain and its effects.
• Individual students: Design a word-find puzzle using the
words in the GLOSSARY of this guide.
• Individuals: Contact a local NATURAL RESOURCE
SPECIALIST from your local zoo or park and ask that per-
son to tell you about the impact, if any, of both acid rain
and dry deposition in the lakes, forests, or other natural
resources in your area. (An alternative to this would be for
the class to invite a specialist to come and speak on this
topic.) Write down what you have learned in a report to be
given to the teacher or read to the class.
• Classroom: Role playing. Each of you takes the role of an
"interested party" (for example, a fish, bird, coal miner,
factory owner, smokestack, fisherman, farmer, stream,
lake, tree, or forester) in a group discussion on acid rain.
Talk about the effects acid rain has on your character and
then present arguments for or against laws to control acid
rain.
• Field Trip: Visit a local cemetery and observe the wearing
away of the headstones or other grave markers over time.
Military cemeteries use limestone markers which are more
easily affected by acid rain than the granite markers in
some private cemeteries. Can you tell by the dates on the
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marker stones and the condition of the stones which ones
acid rain may have damaged? Remember that these materi-
als would naturally deteriorate when exposed to the
weather and rain (even clean rain). Acid rain would acceler-
ate this damage.
• Individual research: Contact your local power company.
Many power companies use more than one source of power
to make enough electricity for the community. Some also
buy electricity from other power companies. Ask the power
company which is its primary source (hydroelectric, nu-
clear, gas, oil, coal, other) and what other sources it uses.
If they can tell you, find out what percent of their output is
generated by each source. If your company buys from other
companies ask if they know what source generates that
company's electricity. Write down your results in a report
to be read to the class.
• Class or individual: Locate or list energy efficient build-
ings in your community. Contact a local architect or an
architecture department in a local college or university and
invite an architect to visit your classroom to describe how
homes, schools, and office buildings can use energy more
efficiently.
• Individual: Find out if your drinking water is being
treated for acidity. Call or visit the water company. First
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determine the source of your water—well, lake, or river. If
you have a private source of water such as your own well,
ask your parents if the water is treated, and if so, how it is
treated. When talking to a water company, usually a city or
county water authority, ask if and how they treat the water
for acidity. Ask them to tell you the pH of the water before
it is treated and the pH after it is treated. Is it completely
neutralized? Write down their answers in a report to give to
the teacher or read to the class.
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BIBLIOGRAPHY
Readings
Acid Rain
Boyle, Robert H.; Boyle, Alexander R.
New York: Schocken Books, 1983
Acid Rain
Gay, Kathlyn
New York: Franklin Watts, 1983
(Available from: New Order Department, Franklin Watts,
Sherman Turnpike, Danbury, CT06816. $11.50--quantity
discount available)
Acid Rain
McCormick, John
New York: Gloucester Press, 1986
Acid Rain: A Plague Upon the Waters
Ostmann, Robert
Minneapolis, MN: Dillon Press, 1982
Acid Rain: A Sourcebook for Young People
Miller, Christina G.; Berry, Louise A.
New York: Julian Messner, 1986
Acid Rain Kids Handbook
Washington, DC: National Geographic Society, 1988
Acid Rain Reader
Stubbs, Harriet S.; Klinkhammer, Mary Lou, and Knittig,
Marsha
Raleigh, NC: Acid Rain Foundation, 1989
Acid Rain Study Guide
Hunger, Carolyn; Pfeifer, David; Hallowell, Anne
Wisconsin Department of Natural Resources
(Available from Wisconsin Department of Natural
Resources, Box 7921, Madison, WI 53707)
For Crying Out Cloud: A Study of Acid Rain
Coyne, Martha
Minneapolis, MN: Tasa Publishing Co., 1981
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Acid Rain Sourcebook
Going Sour: Science and Politics of Acid Rain.
Gould, Roy
Cambridge, MA: Birkhauser Boston, Inc., 1985
"How Scientists Are Tracking Acid Rain"
Gannon, Robert
Popular Science, August 1984, p. 67-71
Rain of Troubles
Pringle, Laurence
New York: MacMillan, 1988
Troubled Skies, Troubled Waters; The Story of Acid Rain
Luoma, Jon R.
New York: Viking Press, 1984
Audiovisuals
Acid Rain (software for Apple Computers)
(Available from: Diversified Educational Enterprises, 725
Main St., Lafayette, IN 47901)
"Acid Rain: New Bad News" (video, 58 minutes)
NOVA/WGBH Educational Foundation
(Available from U. of Michigan Film & Video Library, 313/
764-5360. Rental fee $20.50)
Air Pollution (Software for Apple or TRS-80 Model III & IV)
(Available from: Educational Materials and Equipment Co.,
PO Box 17, Pelham, NY 10803)
"Decision: Energy for the Future" (film or video, 11
minutes)
Earth Metabolic Design
(Available from: Bullfrog Films, 800/543-FROG or 215/
779-8226. Purchase price for 16mm $250, video $65;
rental fee $25)
"For the Long Run" (video, 20 minutes)
National Park Service
(Available from: National Park Foundation, P.O. Box 57473,
Washington, DC 20037, 202/785-4500. Purchase price
$65; call for catalog).
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Acid Rain Sourcebook
"Into Deep Waters" (video, 26 minutes)
Bellamy, David
(Available from: Bullfrog Films, 800/543-FROG or 215/
779-8226. Purchase price for 1/2" video $250, 3/4" $265;
rental fee $50)
"Problems of Conservation: Air" (film, 15 minutes)
NOVA/Encyclopaedia Britannlca Educational Corporation
(Available from: U. of Michigan Film or Video Library, 313/
764-5360. Rental fee $15.40)
HRunning Out of Steam" (video, 26 minutes)
(Available from: Bullfrog Films, 800/543-FROG or 215/
779-8226. Purchase price for 1/2" video $250, 3/4" $265;
rental fee $50)
The Sky's the Limit" (film or video, 23 minutes)
Ken White
(Available from; U. of California Extension Media Center,
415/642-0460. Purchase price for 16mm film $450, video
$310; rental fee $40)
"Still Waters" (film, 57 minutes)
NOVA
(Available from U. of Michigan Film or Video Library, 313/
764-5360 or 800/999-0424. Rental fee $35.35)
"Water: A Precious Resource" (film or video, 23 minutes)
(Available from: National Geographic Society Educational
Services, 800/368-2728. Purchase price for video $69.95,
film $240)
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GLOSSARY
Acid Any of a large group of chemicals with a pH less than 7.
Examples are battery acid, lemon juice, and vinegar.
Acidic Describes an acid. For example, lemon juice is acidic.
Acid Rain Wet precipitation that has become acidic by contact with
air pollution. Other forms of precipitation, such as snow and fog,
are also often included in the term acid rain or acid deposition.
Alkaline Describes a substance such as baking soda, milk of
magnesia, or ammonia, that can dissolve in water and neutralize
acids.
Aquatic Growing or living in water.
Atmosphere The air or gases that surround a planetary body such
as the earth.
Base Any of a large group of chemicals with a pH greater than 7.
Examples are ammonia and baking soda dissolved in water.
Basic Describes a base. For example, alkaline materials are basic.
Buffer A substance, such as soil, bedrock, or water, capable of
neutralizing either acids or bases.
Buffering Capacity The ability of a substance to resist changes in
pH when acids or bases are added.
Carbon Dioxide A colorless, odorless gas made of the elements
carbon and oxygen. Animals exhale carbon dioxide and automobile
exhaust contains carbon dioxide.
Catalytic Converter A device that burns off pollution from exhaust
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gases. Commonly used in automobiles and required on all cars sold
in the United States since 1973.
Chemical A substance made up of elements combined together.
Condense To change from gas or vapor to liquid form.
Dry Deposition The falling of small particles and gases to the earth
without rain or snow.
Ecosystem The relationships among animals and plants and their
environment in a particular area.
Energy The power to do physical work. Electricity and heat are
energy sources.
Environment The combination of all conditions surrounding living
things.
Fossil Fuels Oil, natural gas, coal, and similar products that are
taken from the earth and used for energy. Fossil fuels were made in
nature from ancient plants and animals.
Habitat The place where a plant or animal lives and grows, such as
a forest, lake, or stream.
Hydroelectric Power The production of electrical energy using
water power.
Hydrologic Cycle The movement of water from the atmosphere to
the surface of the land, soil, and plants and back again to the
atmosphere.
Limestone A rock that is made from ancient shells and coral.
Limestone contains calcium carbonate and is a base.
Liming Adding crushed limestone to lakes, streams, or other
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bodies of water is called liming and it raises the pH of the water.
Litmus Paper Paper coated with a chemical coloring obtained from
lichens that turns red in acidic water and blue in basic water. It is
used as an acid-base indicator.
Natural Resources All the parts of the earth that are not human-
made and that people use, like fish, trees, minerals, lakes, or rivers.
Natural Resources Specialist A person who knows a great deal
about animals and plants and where they live—for example,
naturalist, forester, forest ranger, etc.
Neutral A substance that is neither an acid nor a base and has a
pH of 7. Neutral substances can be created by combining acids and
bases.
Neutralize To combine acids and bases to make a neutral
substance or solution. For example, acidic water can be neutralized
by adding a base, such as limestone.
Nitric Acid An acid that can be produced in the atmosphere from
nitrogen oxide.
Nitrogen Oxides A family of gases made up of the elements
nitrogen and oxygen commonly made by burning fossil fuels.
Nuclear Power Energy that comes from the center (nucleus) of an
atom.
Ozidants Chemicals that supply oxygen to other chemicals when
they are combined in a chemical reaction.
Particles Tiny solid fragments that float in the air, such as dust.
pH Scale The range of units that indicate whether a substance is
acidic, basic, or neutral. The pH scale ranges from 0 to 14; a pH of
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7 is neutral, lower than 7 is acidic, and greater than 7 is basic.
pH Paper Paper that changes color to show the pH of a substance.
Photosynthesis The process that plants use to convert sunlight to
energy to live and grow.
Plankton Tiny organisms that float or drift in water and serve as a
food source for larger animals such as fish.
Precipitation Mist, sleet, rain, hail, or snow falling to the earth.
Pollutant A harmful chemical or other unwanted substance
released into the environment by human activity.
Pollution Chemicals or other substances that are harmful to or
unwanted in the environment.
Reactive Having the tendency to chemically combine with
something else and change its form. For example a strong acid is
highly reactive with a strong base.
Reservoir A place where water is collected and stored for use,
usually in an artificial basin created by damming a river.
Runoff Water that flows off land into lakes and streams.
Scrubber A device that removes air pollution, mainly sulfur
dioxide, from smokestacks.
Solar Energy Energy that comes from the sun.
Solution A uniform mixture formed by dissolving a substance in
liquid.
Sulfur Dioxide A gas made of sulfur and oxygen that is released
when coal is burned.
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Sulfuric Acid An acid that can be produced in the atmosphere
from sulfur dioxide. Sulfuric acid is used in automobile batteries.
Toxic Poisonous to some living thing.
Turbine A motor activated by water, steam, or air to produce
energy.
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•fsV.S. GOVERNMENT PRINTING OFFICE: 1990 • 74H-IS9/204*6
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