The Effect of Acid Rain on Radish Growth

Researched by Emily H.
2002-03

PURPOSE

The purpose of this experiment was to determine to what degree the pH of water affected the growth of radishes. 

I became interested in this idea when I found out that acid rain is a growing problem in many countries and continues to cause damage to forests, crops, and wildlife. 

The information gained from this experiment could help scientists, and people around the world know the effect of acid rain on crops and gardens.

HYPOTHESIS

My hypothesis was that the lower the pH, the more the growth of radishes would be harmed and the less they would weigh. 

I based my hypothesis on a quotation Plant Biology Science Projects, by David R. Hershey that states on page 101 "…plants generally grow better at the higher soil pH."

EXPERIMENT DESIGN

The constants in this study were: 

  • The amount of potting soil
  • The type of potting soil
  • The temperature radishes were grown in 
  • The kind of radish
  • The procedure to measure the bio mass of the radishes
  • The amount of water
  • Size and type of containers the radishes were grown in
  • The number of radishes per pH level
The manipulated variable was the pH of water put on the radishes. 

The responding variable was the average biomass of the radish plants after 24 days of growth. To measure the responding variable I used a triple beam balance 

MATERIALS
QUANTITY ITEM DESCRIPTION
140 radish seeds (cherry belle)
1 triple beam balance
purified water
15 pH water (ml)
1 grow light
1 graduated cylinder
140 plastic cups 3 oz.
1 potting soil
1 pair scissors
4  cookie pans
2 suitcase locks
1 shower bar
4  empty gallon size jugs

PROCEDURES

1. Cut two holes on opposite sides of cup at least an inch long.
a.) fill 2/3 of a cup up with potting soil
b.) put one radish seed in the middle of the cup
c.)  fill the the cup up with potting soil, leaving soil nice and loose
3. Complete 2 a-c until all 140-radish seeds are planted.
4. Put into 4 groups 35 per cookie sheet, label them pH 7.0, pH 5.0, pH 4.0, and pH 2. 
5. Put all 4-cookie sheets in the bathtub.
6. Take down the bar from your shower curtain and put it about 2 feet above the radishes making sure it is secure. Put the chains of the grow light over the bar and use the suitcase locks to lack in place.
7. In each cup put 15 milliliters of water in each cup. Repeat this every other day.
8. Place saran wrap over the radishes to keep in the moisture and to prevent molding.
9. Next set the light timer for it to start at 7:00 am and for it to turn off at 5:00 pm. 
10. After two weeks of watering the radishes, begin watering radishes with the different pH levels for 2 weeks following. 
a.) choose pH levels (2,4,5,7)
b.) start by filling a 1-gallon cup w/ ultra pure water.
c.) Put the 18 megaohm measuring probe in the water until the display stops.
d.) Then add sulfuric acid to the water w/ an eyedropper.
e.) When you reach pH2, with help, put a funnel in the top of a gallon jug having someone holding the funnel, pour the pH2 water into the jug. Put the cap on the jug and label it pH2.
f.) Clean out gallon cup w/ ultra pure water.
g.) Repeat steps 3-7 only changing the water to pH4.
h.) Repeat steps 3-7 but instead of changing water to pH2 or pH4, change water to pH5. In f do not add sulfuric acid but instead add sodium Hydroxide until you come up with pH5 on the 18megaohm-pH meter. 
i.) Repeat steps d-e, g-h, and j.
j.) Instead of coming up with pH5 you should come up with pH7.
11. After 2 weeks of watering with pH carefully dig the radishes out of the soil. Lay them on a paper towel with one of the pH4 levels written on it. Do this for all four of the pH levels.
12. Next take all of the radishes from the pH2 group, place them on the triple beam balance and weigh them.
13. Repeat 12 but weigh the other 3 pH levels. Write down the results.

RESULTS

The original purpose of this experiment was to determine to what degree the pH of water affected the growth of radishes. 

The results of the experiment were radishes grown at pH 5 did the best growing an average of 20.7 grams, the second heaviest group was pH 7 with and average of 16.1 grams, the third heaviest was pH 4 with an average of 16.2 grams, and the fourth heaviest was pH 2 with an average of 6.1 grams. 

See the table and graph.

CONCLUSION

My hypothesis was that the lower the pH, the more the growth of radishes would be harmed and the less they would weigh.

The results indicate that this hypothesis should be rejected.

Because of the results of this experiment, I wonder if more agriculturally important species like wheat or rice would be affected by acid rain. Also I wonder if alkaline water would affect plant growth. 

If I were to conduct this project again I would have had more radishes in each group, would have observed more and written my observations in my log book, and would have used different kind of acids. 

Research Report

Introduction

 Plants play a vital role in the survival of the human race. The most important contribution is the oxygen produced by plants, which allows human beings to live. The other essential use of plants by humans is food. The nutrients in plants keep humans healthy and strong. When pollutants like acid rain harm plants it can jeopardize humans. 

Acid Rain

Acid rain is any polluted precipitation, such as rain, snow, fog, sleet, etc. It harms bodies of water, kills wildlife, damages statues, buildings, or bridges, harms soil and forests. It takes a large amount of acid rain to harm forests. 

Acid rain forms when water vapor reacts with chemicals such as sulfur dioxide or nitrogen dioxide, which comes from burning coal, gasoline, and oil. The places affected by acid rain are North America, Scandinavia, Central Europe, and Asia. In many populated areas acid rain has increased tremendously since the 1950’s. This happened because in urban areas taller smokestacks were built and used, then the wind blew smoke away from the source.  People have ways to make the air less acidic.  They can use devices to remove sulfur and nitrogen from the air.  Also they add lime to lakes and rivers, which temporarily decreases the acidity, but the liming may have a bad side effect.  Some lakes are able to resist acid rain because the soil contains lime, which makes the acid less harmful.  Some of the lake areas affected are in Sweden, Canada, New York, Minnesota, and Norway.  More factories mean more acid rain, which affects countries such as Zambia, Malaysia, and Venezuela. 

Acid rain can also be called acid deposition which is separated into dry deposition and wet deposition.  Dry deposition is mostly gases and particles.  Wet deposition is rain, fog, sleet, snow, etc.  Acid rain is measured by pH.  The two main acids in acid rain are sulfuric acid and nitric acid.  The EPA or The National Atmosphere Deposition Program measures wet deposition.  Cast Net or Clean Air Status and Trends Network measures dry deposition.  Industrial plants give off 50% of the nitrogen oxide emissions in the USA.  Cars are the largest single source for nitrogen oxides. 

Nitric Acid

Nitric acid is produced from thunderstorms, and falls to earth in rain. This chemical is very weak. Nitric acid can be manmade two different ways. The first way is by oxidizing ammonia with a platinum catalyst. Then ammonia and air pass through heated platinum gauze. They react by making a water nitric oxide and nitrogen oxide. While cooling, the mixture forms nitric acid. This process is called the Ostwald process, after Wilhelm Ostwald, a German scientist. The second way is by heating saltpeter and sulfuric acid together. This is a colorless liquid with a horrible smell that can suffocate. It turns yellow if it is not in a tightly sealed bottle. Nitric acid has many uses including industrial uses and fertilizers. Also it is an ingredient in explosives, flares, and rocket propellants. Nitric acid was one of the first known acids. Nitric acid is an inorganic substance that dissolves many metals but not gold or platinum. Also it’s used to make nylon, organic compounds, and drugs.

Sulfuric Acid

Sulfuric Acid is a colorless, dense, oily liquid, which can be very corrosive. This acid is one of the most important chemicals for manufacturing. Sulfuric acid is one of the strongest acids. It can burn skin; irritate the lining of the nose, windpipe, and lungs. Sulfuric acid is used for making fertilizers, refining petroleum, producing car batteries, explosives, iron, metals, paper pulp, producing organic chemicals, dyes, and medicine. There are two ways to create sulfuric acid. The old way was the lead-chamber method, but now mostly the contact method is used. The lead chamber method starts with burning sulfur dioxide. The sulfur dioxide is put with nitrogen in nitric oxides, which creates sulfuric acid. This process is inexpensive, but produces a weak acid. The second and more commonly used method is the contact method. First sulfur trioxide passes sulfur dioxide through a heated platinum tube. Then sulfur trioxide, dissolved by concentrated sulfuric acid, make oleum. Oleum is then added to water creating sulfuric acid. This process creates a much stronger acid than the lead-chamber method. 

PH

PH stands for "power of hydrogen." This is measured from a scale of 0-14 and 7 is neutral. The values below 7 are acidic and the values above 7 are basic. For every up or down on the scale the pH level is increased or decreased by a power of 10. The two main acids that are measured by pH are sulfuric acid and nitric acid. Many organisms are able to adapt to many different pH levels. Ammonia increases in toxicity with the rising of pH levels. Starting at a pH value of 6 and lower nitrifying bacteria experience a growth reduction. Some personal protection tips while using lower pH levels are: wear glasses or goggles, wear a facemask, where acid-resistant gloves, and have suitable ventilation.

Radishes

Radishes come from the family Brassicaceae, the mustard family, or Cruciferae. The scientific name is Raphanus atirus. They can be many shapes and colors. Some of these shapes are icicle, oval, or round. Also the colors can be white, red, black, yellow, pink, red and white, and purple. The weight is from 28 grams to 1 kilogram. In the US radishes are harvested in March, April, and May. The leading radish growing states in the US are Florida, California, and Ohio. Also they are grown in gardens and after 20-60 days are ready to eat. Plus they can handle frost and are gown in colder weather. Radishes are used in salads, as appetizers, food, clothing, ink, paper, fuel, plastic, medicine, perfume, soap, dyes, paint, rubber, rope, sports equipment, and photo film.

Soil

Soil has many uses. Some of these uses are homes for animals, collecting nutrients, and as a source of food. Bacteria in soil make other things decay or rot. Soil contains minerals, organic particles, other plants, animal matter, air, and water. These contents are changing all the time. Different soil contains different things. Soil covers most of the Earth’s surface. Scientists that study soil are called pedologists. Soil forms slowly and can be destroyed easily.

Summary

Humans cannot exist without plants. They supply oxygen and food for the planet. Pollution created by man has begun to destroy the vegetation resulting in less oxygen and less food supply. A greater effort should be made to stop pollution like acid rain and protect the plant life on which humans depend. 

 BIBLIOGRAPHY

"Acid Rain." August 6, 2002 http://www.policyalmanac.org/environment/archive/acid_rain.shtml

"Acid Rain." Rhonda Fabian and Jerry Baber. 1993.

"Air Pollution and Acid Rain." Encarta. 2001.

Amdur, Richard. The Fragile Earth. New York, Philadelphia: Chelsea House Publications, 1994. Pp. 73, 87.

Busch, Marianna A. "Nitric Acid." World Book Encyclopedia. 1998.

Edelson, Edward. Clean Air. United States: Chelsea House Publishers, 1997. 
Pp.16-17, 37-40, 55-56, 83, and 85.

Hershey, David R. Plant Biology Science Projects. Canada: John Whiley & Sons, Inc., 1995. p. 101.

Hoff, Mary and Roders, Mary M. Our Endangered Planets and Lakes. United States: Lerner Publications Company, 1991. Pp.40-41.

Hughes, George R. "Radish." World Book Encyclopedia. 1998.

Likens, Gene E. "Acid Rain." World Book Encyclopedia. 1999.

Meyer, B. "Sulfuric Acid." World Book Encyclopedia. 1998.

"pH Level." November 18, 2002 http://www.malibuwater.com/pH-Level.htm/

"Safety (MSDS) Data for Nitric Acid." November 18, 2002 http://www.ptcl.chem.ox.ac.uk/MSDS/NI/nitric_acid.html/

"Soil." World Book Encyclopedia. 1998.

ACKNOWLEDGEMENTS

    I would like to thank the following people for making my science project possible:

  •  Mr. Newkirk for making corrections on my journal and report and for helping me with my graphs. Also for letting me borrow a grow light and a triple beam balance.
  •  Mrs. Helms for helping me with any questions I asked and for correcting my papers. 
  •  My mom for helping me gather my materials, pushing me to get things done, and when I wasn’t home to water my radishes she helped me out. Also for picking me up from after school classes.
  •  My dad for picking me up from after school late classes. Also asking questions about my project to make me better understand it. 
  •  Mr. Eisele for guiding me throughout my making of the pH water and teaching me how to use the materials needed.
Top of page

Menu of 2002-2003 Science Projects

Back to the Selah Homepage