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The Effects of Acid Rain on Plant Growth

Researched by Eric D.


The purpose of this experiment was to determine to what degree acid rain affects the growth of certain plants. 

I became interested in this idea because I’m worried about our environmental conditions and it sounded very interesting to me.

The information gained from this experiment may be used to as a warning to stop air pollution. 



My hypothesis is that the plant watered with the acid solution will grow more slowly than plant’s watered with regular rainwater.

I base my hypothesis on a book that has a picture of a tree that acid rain has fallen on compared to a regular tree.

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The constants in this study were:

*The temperature where the plants were grown.
*The type of plant tested.
*The amount of water each day. 
*The amount of sunlight each day.
*The amount of soil in each pot.
*The type of soil in each plant.
*The size of the pot.
*The shape of the pot. 

The manipulated variable was the amount of acid in each watering solution.

The responding variable was the growth of each plant.

I will use a centimeter ruler to measure the responding variable, which is the height of the plant.

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4  plastic pots
spray bottles
1  pH metercfr or pH paper
2 eye droppers
 liters of distilled water
1 marking pen
8 marking pen
1 Source of light
1 Bag of Potting soil
 Bottle of lemon Juice

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1. Fill each pot to the top with the potting soil.
2. Label one pot "acid" and the other "normal".
3. Place a seed into slightly moisted soil in each pot.
4. Water the seeds and soil.
5. Place both pots under a source of light.
6. Every two days, water with distilled water and place in the light.
7. Repeat step 6 until each plant has fully expanded a pair of leaves.
8. Pour 1 liter of distilled water into one of the empty spray bottles.
9. Mix 1 liter of distilled water with 5 drops of lemon juice and pour into the other spray bottle.
10. Measure the acid solution with a pH meter or a pH paper. It needs to be around 3.
11. If too much acid, pour in more distilled water.
12. If not enough acid, keep adding until it reads about 3.
13. Mix by swirling water around.
14. Label the bottle with distilled water normal and the acid solution bottle acid.
15. Mist the leaves of the normal pot with its matching spray bottle.
16. Let leaves dry, then place in original growth spot.
17. Mist the leaves of the acid pot with its matching spray bottle.
18. Let leaves dry, then place in original growth spot.
19. Repeat steps 15-18 until obvious results. 

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The original purpose of this experiment was to determine whether the plants would be affected by an acid solution.

The results of the experiment were that the plants tested with an acid solution died and the other plants tested with distilled water lived.

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My hypothesis was that the plant tested with an acid solution would not live and the plant tested with distilled water would live.

The results indicate that this hypothesis should be accepted. 

Because of the results of this experiment, I wonder if I had put in a smaller amount of acid in the solution if it would still affect the growth. 
Another thing I wonder about is if I would've used different plants if the results would be the same. 
I also wonder if I would have used a different type of acid if it would effect the results of this experiment.

If I were to conduct this project again I would probably add less acid to that solution and I would also test more plants.

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Acid Rain is the common name for acid deposition, such as rain, snow, sleet, hail, and other forms of polluted precipitation. Acid deposition is a worldwide problem for all natural things including bodies of water, forests, and other things. Pollution is the cause of all acid deposition. 

There are many types of pollution that cause acid precipitation. A big one is cars and their exhaust. The usage and burning of fuel and oil creates a lot of exhaust. Another big pollution problem is factories and refineries that burn fuel, oil, and coal. Then certain chemical compounds, including sulfur dioxide and nitrogen oxides, from fossil fuels, rise and mix with water vapor, and falls in a form of precipitation. As factories have been getting more and taller smokestacks, Acid precipitation has been moving more around the world. Acid precipitation is worst in eastern North America, Northwestern and Central Europe, throughout Asia, and other scattered places around the World. As more factories and refineries are built, and the smokestacks get taller, the wind blows the polluted air to other countries, sometimes hundreds of miles away.

The pH Level
 Acid rain’s acid level is measured by the pH level. The scale is measured on a 1-14 number scale, 1 being the most acidic and 14 being the most alkaline. A 7 is not either acidic nor alkaline, being known as distilled water. To measure the pH level of acid precipitation, scientists use a pH meter or a pH paper. On average, a normal pH level for acid precipitation is around 5.6. The more pollution in the atmosphere, the more acidic the acid precipitation is going to be. Depending on the pH level, acid precipitation can do a lot of damage.

The effects of Acid precipitation are getting worse as more cars are manufactured and sold to the public and as more factories are built and opened for people to work in. Acid precipitation harms thousands of lakes, ponds, rivers, and streams worldwide. Depending on the pH level, acid precipitation could kill and damage almost all of the aquatic life, including the animals, plants, and all of the other living things in that body of water. The acid rain also kills everything around that body of water, including the trees, bushes and the grass around the surface of the water. Some scientists also believe that Acid Rain does damage to stone buildings and stone statues. They believe it erodes away the stone. Acid shock is a very interesting form of the acidifying of a body of water. It happens during the spring. The acid snow melts and flows into a body of water. Its called acid shock because it turns a normal lake or other body of water into a very acidic body of water in a very short amount of time.

There are not very many ways to prevent acid rain and other acid precipitation. Scientists are trying to think of more ways to prevent acid precipitation. There are already a few methods of cleaning up the atmosphere, including cutting back on fuel, oil, and coal burning. Some factories throughout the world have coal washers. That prevents air pollution, but the water from the coal gets dumped into a sewer and creates more sewage problems. There have been several attempts to stop local factories by people in the past, but then realized they couldn’t live because the factories provided warmth and electricity, so they couldn’t shut them down. After people got taller smokestacks, the pollution was getting better there, but worse in other countries. The reason is the wind blew the clouds hundreds of miles away. Also, some people have tried to stop driving as much, but at the end, everybody was driving again, doing just as much of it as they were before if not more. The pollution would be less in that area, but worse in other areas, so the people in that area would drive more, thinking its okay.

 Acid Rain and all other acid precipitation are a world wide problem. Even in areas with out the factories and vehicles have acid precipitation because the wind blows the pollution to other parts of the world. The main causes of acid precipitation are cars and their exhaust and the other is factories and the burning of fossil fuels. Certain chemical compounds such as nitrogen oxides and sulfur dioxide mix with the moisture in the air and are formed into clouds and then produce acid precipitation. To measure the acid level of acid precipitation, scientists use either a pH meter or a pH paper. The scale is on a 1-14 scale, 1 being the most acidic and 14 being the most alkaline. The average acid level is around 5.6. Depending on the pH level acid precipitation can do a lot of damage. The effects of acid precipitation are getting worse as more cars and factories are made. Acid precipitation is damaging thousands of lakes, ponds, rivers, and streams worldwide. There aren’t many forms of prevention, but the best form of stopping air pollution is washing the coal before it is burned. The con to that is the remains of dirty water from the coal is dumped and it causes more sewage problems.

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“Acid Rain,” Compton’s Interactive Encyclopedia, 1995

“Acid Rain,” Compton’s Interactive Encyclopedia, 2000

Acid Rain [online] Jan 4,2000

Acid Rain [online] Jan 11, 2000

Brooks, John “Acid Rain” Chicago, Illinois, 1997 pp. 2-37

Likens, Gene E. “Acid Rain,” World Book Encyclopedia, 1991 Vol. 1 p. 27



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