Acid Rain Lab
Collaborators: Kevin, Sneha, Riordan, Brandon, Sharon, Megan, Sarah
Introduction and Problem
The goal of this Acid Rain lab is to test how acid rain affects the growth of grass. This topic is highly invaluable in being able to fully understand the necessity of reducing the human activities that create and continue to increase the amount of acid rain. The normal pH of rainwater is between 5 and 5.5; however, acid rain has a pH of 4, meaning that it is 10 times more acidic than regular rainwater ("PH Scale"). Acid rain is formed when the gases sulfur dioxide and nitrogen oxide are released into the atmosphere and react with water, oxygen, and other chemicals to form more acidic pollutants ("What Causes Acid Rain?"). These gases are created both through natural sources, such as volcanoes, as well as through man-made sources, like power plants that use fossil fuels like coal to produce electricity or the exhaust from cars. Scientists are becoming greatly concerned with the threat that acid rain poses to the environment and the humans that occupy it. Acid rain causes health problems such as respiratory diseases, harms forests by dissolving the soil’s nutrients, damages lakes and streams by making the water more acidic and affecting the ecosystem and life in the water, and damages buildings and objects by causing the paint to peel and deforming stone statues ("Why Is Acid Rain Harmful?"). Overall, acid rain is an increasing threat that needs to be addressed and reduced, and the best way to do that is by having a full understanding of the implications of the acidic pollutant.
Hypothesis
This experiment is testing the effects of different pH’s on fescue plants. When using these three substances, I predict the distilled water will preserve the fescue plant while the other two will kill it, however the lowest pH of 2.4 (white vinegar) will destroy the grass the fastest.
Parts of the Experiment
Independent Variable: pH of water
Dependent Variable: effects on the grass
Control Variables: fescue grass, 2 liter bottles, amount of time over which the grasses are grown and tested
Control group: grass with distilled water
Experimental group: grass samples with different pH levels (pH 2.4 and 8)
Materials and Methods
The items needed to perform this experiment included nine 2L used soda bottles containing fescue plants, white vinegar, distilled water and sunlight.
The first step was to pour 1 teaspoonful of white vinegar into 2 cups of distilled water and stir well. The pH is checked with pH paper or a garden soil pH testing kit. The goal is that the pH of the vinegar/water mixture is close to 4. If, however, it is below a pH of 4, a sprinkle of of baking soda or drop of ammonia is added. The mixture is stirred well again and the pH is rechecked to ensure the pH is close to 4. If the mixture is above a pH of 4, a drop or two of vinegar is added and the pH is rechecked as above. The final pH is then recorded. Next, the pH of the distilled water is measured and recorded. Finally, another pH solution of choice is created. The actual pH is measured and recorded. If the pH is below 7, about 1/8 teaspoonful of baking soda or a drop of ammonia is added. The mixture is then stirred well and the pH is rechecked with the pH indicator. If the solution is still acidic, the process is repeated until a pH of at least 7 is reached. If too much baking soda or ammonia is added, a few drops of vinegar are added, then the pH is rechecked and recorded.
Each group is responsible for watering 2 plants once weekly according to the following method: blue plants receive 50mL of water only, yellow plants receive 50mL of solution 1, and pink plants receive 50mL of solution 2.
Data and Data Analysis
Data
Group 1 / Week / Control / pH 2.4 / pH 81 / Green in color with a few yellow strips / Green in color with a few yellow strips / Green in color with a few yellow strips
2 / Same as week one / Primarily yellowish in color and strips of grass shriveled and entangled together / Even mix of green and yellow strips of grass and strips that are slightly shriveled but equally spread across the soil in the bottle
3 / Mostly yellow and entangled grass / Mostly yellow strands of grass and laying flat against the soil / Mostly yellow strips with a few green strips and still growing straight up
Week 2
(Distilled) (pH 2.4) (pH 8)
Week 3
(Distilled) (pH 2.4) (pH 8)
Analysis
Throughout this lab, we observed and recorded the affect that the different solutions being tested had on the fescue plant overtime. Ultimately, by the end of the 3 weeks, all three of the grass samples were dead due to the lack of sufficient watering throughout the experimental process. However, I observed that both the white vinegar (pH 2.4) and the solution with a pH of 8 seemed to have an earlier and more drastic affect on the grass than the distilled water. By the third week, the grass sample that had been applied with white vinegar seemed to be more deteriorated and withered than the pH 8 sample. If we had sufficiently watered the control sample throughout the experiment, it would have remained alive and healthier, and the pH 2.4 would have more obviously killed the grass quicker and more completely. However, as observed by the pictures of the grasses samples from week three, the white vinegar seemed to have a greater negative affect than the other two solutions.
Conclusions
At the beginning of this lab, I hypothesized that the distilled water will preserve the fescue plant while the other two will kill it, however the lowest pH of 2.4 (white vinegar) will destroy the grass the fastest. After performing the lab, I discovered that my hypothesis was accurate. The results of the experiment concluded that the more acidic solution had the quickest and more drastic effect on the grass sample than the other two solutions. This experiment proves the negative affect that acid rain has on the plants of vegetation of the earth, thereby negatively affecting the animals and humans that consume them.
As seen from this experiment, acid rain causes slower growth, injury, or death to plants as well as soil degradation. The topic of acid rain is a direct result of air pollution and a direct cause of biosphere destruction. Therefore, one major way to prevent acid rain is to reduce the amount of pollution being given off, especially from the burning of fossil fuels. This can be done by using coal that contains less sulfur in order to reduce the amount of sulfur dioxide released into the atmosphere, utilizing other renewable sources of energy such as wind and solar, and developing new technologies such as the catalytic converter to reduce the amount of pollution given off by transportation vehicles like cars and trucks. Humans must make more of an effort to reduce the activities which create the most pollution, because otherwise, the balance of the ecosystems in the environment and the survival of many species around the world could be at stake.
Works Cited
"PH Scale." EPA. Environmental Protection Agency, n.d. Web. 03 Dec. 2014.
"What Causes Acid Rain?" EPA. Environmental Protection Agency, n.d. Web. 03 Dec. 2014.
"Why Is Acid Rain Harmful?" EPA. Environmental Protection Agency, n.d. Web. 04 Dec. 2014.