This document summarizes an experiment on the impact of acid rain conducted by two biology students. The experiment included three activities: 1) measuring the solubility of limestone in lemon juice, vinegar, and water, 2) observing the effects of submerging flowers in lemon juice and water, and 3) observing the effects of applying vinegar and water to plant leaves. The results showed limestone was most soluble in vinegar, flowers were damaged in lemon juice and wilted in water, and leaves treated with vinegar yellowed and dried out while leaves in water wilted slightly. The discussion concludes that acid rain reduces soil nutrients and pH, releasing aluminum which inhibits plant growth and causes leaves to fall off or wilt.

1. REPORT EXPERIMENT BIOLOGY
“ACID RAIN”
Team Member:
Desika Galore Sirait 4163342009
Dinda Arifanni 4163342011
Major : Biology
Date of Experiment: May, 22th 2017
Study Program : BILLINGUAL BIOLOGY EDUCATION 2016.
DEPARTMENT OF BIOLOGY
FACULTY OF MATHEMATICS AND NATURAL SCIENCES
THE STATE UNIVERSITY OF MEDAN
MEDAN
2018

2. 1
I. Tittle : The impact of acid rain
II. Purpose :
- Able to explain the notion of acid rain
- Able to explain the mechanism of acid rain
- Able to explain the solution to overcome the impact of acid rain
- Know the effect of acid rain on plant growth
III. Literature Review :
What is Acid Rain
Acid rain refers to a mixture of deposited material, both wet and dry, coming from
the atmosphere containing more than normal amounts of nitric and sulfuric acids. Simply
put, it means rain that is acidic in nature due to the presence of certain pollutants in the air
due to cars and industrial processes. It is easily defined as rain, fog, sleet or snow that has
been made acidic by pollutants in the air as a result of fossil fuel and industrial combustions
that mostly emits Nitrogen Oxides (NOx) and Sulfur Dioxide (SO2). Acidity is determined
on the basis of the pH level of the water droplets. Normal rain water is slightly acidic with a
pH range of 5.3-6.0, because carbon dioxide and water present in the air react together to
form carbonic acid, which is a weak acid. When the pH level of rain water falls below this
range, it becomes acid rain.
Acid rain is defined as all kinds of rain with pH below 5.6. This type of acid in rain
is very beneficial because it helps dissolve the minerals in the soil needed by plants and
animals. Acid rain is caused by sulfur (sulfur) which is an impurity in fossil fuels and
nitrogen in the air that reacts with oxygen to form sulfur dioxide and nitrogen oxide. These
substances diffuse into the atmosphere and react with water to form sulfuric acid and
soluble nitric acid so that it falls with rain water. The acid rain water will increase the
acidity of soil and surface water that proved to be harmful to fish and plant life (john,
Alexander.1997)

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When these gases react with water molecules and oxygen among other chemicals
found in the atmosphere, mild acidic chemical compounds such as sulfuric and nitric acid
are formed resulting to acid rain. Acid rain generally leads to weathering of buildings,
corrosion of metals, and peeling of paints on surfaces. Erupting volcanoes contains some
chemicals that can cause acid rain. Apart from this, burning of fossil fuels, running of
factories and automobiles due to human activities are few other reasons behind this activity.
(Walker, Robby. 2004)
Causes
Acid rain describes any form of precipitation with high levels of nitric and sulfuric
acids. It can also occur in the form of snow, fog, and tiny bits of dry material that settle to
Earth. Rotting vegetation and erupting volcanoes release some chemicals that can cause
acid rain, but most acid rain falls because of human activities. The biggest culprit is the
burning of fossil fuels by coal-burning power plants, factories, and automobiles. (Miller C,
William.1987)
When humans burn fossil fuels, sulfur dioxide (SO2) and nitrogen oxides (NOx) are
released into the atmosphere. These chemical gases react with water, oxygen, and other
substances to form mild solutions of sulfuric and nitric acid. Winds may spread these acidic
solutions across the atmosphere and over hundreds of miles. When acid rain reaches Earth,
it flows across the surface in runoff water, enters water systems, and sinks into the soil.
(Hatier.1993)
Effects
Acid rain has many ecological effects, but none is greater than its impact on lakes,
streams, wetlands, and other aquatic environments. Acid rain makes waters acidic, and
causes them to absorb the aluminum that makes its way from soil into lakes and streams.
This combination makes waters toxic to crayfish, clams, fish, and other aquatic animals.
(Johnson.2000)

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IV. Apparatus and Materials :
Apparatus
No Name of Apparatus Amount
1 Indicator pH 7 pieces
2 Tissue Sufficiently
Materials
No Name of Materials Amount
1 Small empty bottle 5 pieces
2 Lime rod 3 pieces
3 Flower buds 2 buds
4 Leaf taro 1 piece
5 lemon juice 600 ml
6 Vinegar 25% 100 ml
7 Water sufficiently
V. Procedure
 Activities A:
1. Filling the 1 bottle with 80ml lemon juice (Solution I)
2. Filling 2 bottles with 80ml vinegar (Solution II)
3. Filling 3 bottles with 80ml water (Solution III)
4. Measuring pH of solution I, II, III with universal indicator pH
5. Insert a piece of 5cm limestone into each solution.
6. Observe which solution of limestone is most soluble and in which solution is the
hardest limestone to dissolve for 5 minutes
 Activity B:
1. Filling the I bottle with 300 ml of lemon juice (Solution I) and bottle 2 with 300 ml
of water (Solution II)
2. Measure the pH of each solution

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3. Submerge each of the two flowers in solution I and II
4. Observe what happens to the flower after 24 hours
 Activities C:
1. Observing the leafy plant
2. Measure the pH of the vinegar solution to be used to smear the leaves
3. Measure the pH of water to be used
4. Apply vinegar on one leaf surface and water on another leaf surface
5. Observe what happens to the leaf for 24 hours.
VI. Result and Discussion
a. Result
Result of Activity A
Nb Bottle Kind of Solution pH of Solution Soluble velocity
1 I Lemon Juice 2 ++
2 II Vinegar 1 +++
3 III Water 6 +
Result of Activity B
Nb Bottle Kind of Solution pH of Solution Explanation
1 I Lemon Juice 2 The flower
being damaged
2 II Water 6 The flower
being withered

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Result of Activity C
Nb Bottle Kind of Solution pH of Solution Explanation
1 I Vinegar 1 The leaf being yellow
or dry out
2 II Water 6 The leaf being small
withered
b. Discussion
On the first day the plants are watered acid solution grows as usual. In all treatments
experienced a long addition but that distinguishes one from the other is the development
and growth of plants and the physical form of the plant.
After watering the solution, it turns peanut plants are still growing, but the growth is
slower than the ordinary water-drenched peanut plants. That's because the sprayed acid
solution dissolves along with the nutrients in the soil that will swab the content before the
nut plant can use it to grow.
In addition, the longer the plants are doused with acidic solutions, the leaves and
stems are smaller than the ordinary water-drenched peanut plants. That's because the
solution will release toxic chemicals such as aluminum, which will mix in the nutrients. So
that if these nutrients are eaten by plants will inhibit the growth and accelerate the leaves
fall or wilt, the rest of the plant will be attacked by disease, drought and death.
Based on the picture, it can be explained that the treated bean plants treated with
acidic water are wilted and there appears to be a dry leaf part. This indicates that the plants
exposed to acid water fertility rate is reduced.
Acidic water can affect plant growth, because acid-containing water that falls to the
ground and stores its water, can dissolve the minerals and nutrients contained in the soil.
Acid water dissolved with nutrients in the soil will sweep the content before the plant can
use it to grow. And will release toxic chemicals such as aluminum, which will be mixed in

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the nutrients. So that when these nutrients are eaten by plants, will inhibit the growth and
accelerate the leaves to fall, the rest of the plant will be attacked by disease, drought, and
die.
Decreased soil pH due to acidic water also causes the release of aluminum from the
soil and cause poisoning. Smooth roots will experience necrosis so that the absorption of
nutrients and water is inhibited. This causes the tree to lack water and nutrients and
eventually die.
High SO2 levels in the forest (associated with acid rain) cause white or brown stains
on the leaf surface, and over a long period of time will cause the death of the plant. Leaves
exposed to acid deposition show low levels of magnesium. While magnesium is one of the
nutrients for plants. Magnesium deficiency is caused by washing of magnesium from the
soil due to low pH and leaf damage causing magnesium leaching in leaves
c. Figure of Experiment :

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Figure 1. Results of activities c
Figure 2. Results of activities B Figure 3 . Results of activities
A

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VII. Conclusion
At pH below 5.6 plant growth is not optimum because at the pH the bacteria nodule
and nitrifikasi process can not run properly. In addition to the pH that is too acidic, the
plant will experience Aluminum poisoning. Aluminum poisoning will inhibit cell division
as a result there will be a shortening of the roots.
Additionally, the acid solution can cause the growth of the bean plant to be slow and
hampered because the sprayed acid solution dissolves with nutrients in the soil that will
sweep the content before the plant can grow. In addition, the solution will release toxic
chemicals such as aluminum, which will mix in the nutrients. So that if these nutrients are
eaten by plants will inhibit the growth and accelerate the leaves fall or wilt, the rest of the
plant will be attacked by disease, drought and death.

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VIII. Refrences
i. Alexander John. 1997. Acid Rain-The Major Cause of Pollution: Its Causes, Effects
and Solution. International Journal of Scientific Engineering and
Technology.Department of Chemical Engineering. (Vol 2)
ii. Robby. Walker. 2004. Clean Air Act Reduces Acid Rain In Eastern United States,
University of Canada, Canada
iii. Ed. Hatier. 1993. "Acid Rain in Europe". United Nations Environment Programme .
University of Indiana. Bangladesh.
iv. William C. Miller, etc.1987. Journal of Science & Geophysical Research.
"Chemistry of precipitation from a remote, terrestrial site in Australia". 92: 13299.
v. Johnson, Noye M. 2000 "Acid Rain". Environment: Science and Policy for
Sustainable Development.University ofpress. UK. Volume 14(2): 33–40.