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Effect of Chlorine Concentration on the Germination of Soybeans

Student Photo

Researched by Joel F.



The purpose of this experiment was to determine the minimum concentration of chlorine that would inhibit 50% of the soybean germination.

I became interested in this idea when I saw on the news that a lot of countries that have sanitizers for their water use chlorine to help purify it. A lot of the citizens will use the water that was previously purified with chlorine on their plants and maybe even their crops. Also soybeans are important to world agriculture and are a large part of the diet in many countries.

The information gained from this experiment could help farmers, botanists and anyone who is involved in or has a job in agriculture.


My first hypothesis was that the 10-milliliter chlorine mixture would prevent the 50% of the seeds from germinating.

My second hypothesis was that the 0.625-milliliter chlorine mixture would not inhibit any of the seeds from germinating.

I based my hypotheses on the fact that the Turkish Department of Wastewater Reuse filters use 1-milliliter to 5-milliliters of chlorine per liter of wastewater in the filtration process. Also the Turkish Department of Wastewater Refuse stated that using more than 5-milliliters of chlorine per liter should prove to have deadly side affects to plants.


The constants in this study were:

∑ The number of soybean seeds in each group.
∑ The amount of light each group receives.
∑ The amount of chlorine water mixture each designated group receives.
∑ The environment the soybeans are grown in such as the temperature, and the humidity.
∑ The type of container the soybeans are grown in.
∑ The type of sand the soybeans are grown in.
∑ The amount of sand the soybeans are grown in.

The manipulated variable was the concentration of chlorine in the water that the soybeans were given.

The responding variable was the percentage of germination of seeds in each group.

To measure the responding variable I counted the number of seeds that germinated in each group.



    3    Graduated Cylinders
1,296    Soybean Seeds
    1 Gallon    Chlorine (Household Bleach)
6    72 cup Garden Planters
1 Marker
1 Pair of scissors
1 Roll of tape
6                         1 Gallon water containers
1 Bag    Pure chemical free playground sand
1    Growth light


1. Labeling the planters.
A. Label the first planter “Control”.
B. Label the second planter “O.625ml”.
C. Label the third planter “1.25ml”.
D. Label the fourth planter “2.5ml”.
E. Label the fifth planter “5.0ml”.
F. Label the sixth planter “10.0ml”.
2. Labeling the water containers.
A. Label the first container “Control”.
B. Label the second container “O.625ml”.
C. Label the third container “1.25ml”.
D. Label the fourth container “2.5ml”.
E. Label the fifth container “5.0ml”.
F. Label the sixth container “10.0ml”.
3. Filling the sand planters.
A. Measure out 30 ml of chemical free playground sand.
B. Pour the sand into the first cup of the Control planter.
C. Repeat procedures “3-A through 3-B” for each of the other cups in all the other planters.
4. Planting the seeds.
A. Plant three soybean seeds in each of the cups for a total of 216 beans planted in each planter.
B. Be sure to plant all the seeds at least a quarter an inch under the sand.
5. Setting up the growth light.
A. Attach a light to a shelf or a surface directly above the planters.
B. Leave the light on all day and all night until the experiment is completed.
6. Mixing the Chlorine Solutions.
A. Using the graduated cylinder measure out 3 liters of water.
B. Pour the water into the container labeled “Control”.
C. This is your control solution.
D. Measure out 10 ml of chlorine.
E. Measure out another 3 liters of water.
F. Mix the 10 ml of chlorine and water together to create the 10 ml chlorine mixture.
G. Pour the 10 ml solution into the 10 ml container.
H. Repeat steps “6-B through 6-F” four more times, except replace the 10 ml of chlorine with the remaining solutions, 5 ml, 2.5 ml, 1.25 ml, and 0.625 ml.
7. Watering the seeds.
A. Water the Control planter with 10 ml’s of water from its matching water container.
B. Repeat step “7-A” with the other planters but water using the planters matching water containers.
C. Water the plants every day until at least 90% of the Control planter germinates.
8. Recoding the results.
A. After germination of 90%of the Control group dig up the plants.
B. Record the number of seeds that germinated.
C. Create a table and graph your results.


The original purpose of this experiment was to determine the minimum concentration of chlorine that would inhibit the germination of soybean seeds up to 50%.

The second original purpose of this experiment was to determine the effect of various concentrations of chlorine, below the 50% inhibiting amount, on the germination of soybeans. 

After 5 days of growth, the results of the experiment were:
∑ 90% of the soybeans in the Control group germinated.
∑ 82% of the soybean seeds in the 0.0625ml group germinated.
∑ 75% of the soybean seeds in the 1.25ml group germinated.
∑ 72% of the soybean seeds in the 2.5ml group germinated.
∑ 60% of the soybean seeds in the 5.0ml group germinated.
∑ 46% of the soybean seeds in the 10.0ml group germinated.


My first hypothesis was that the 10-milliliter chlorine mixture would prevent 50% or more of the seeds germinating.

My second hypothesis was that the 0.0625-milliliter chlorine mixture would not inhibit any of the seeds from germinating.

The results indicate that my first hypothesis should be accepted because 64% of 10ml group did not germinate, that was 54% worse than the control group.

The results also indicate that my second hypothesis should be rejected because 18% of the 0.625ml group did not germinate, that was 8% less that in the control group.

Because of the results of this experiment, I wonder if the soybeans were watered another group with 0.03125ml or 0.015625ml of chlorine would the results be better or worse, I predict better. I also wonder if I watered a group with 15ml or 20ml of chlorine how much of the group would germinate.

If I were to conduct this project again I would conduct it outside in the summertime and I would water them more. I would also use more groups with more seeds. Also maybe use more soil.


Without plants all life would cease to exist. That is why scientists must research what is harmful to plants. The soybean is a very important plant in agriculture in many counties. Chlorine can be very harmful to most plants including soybeans.

 Plants are important to every living thing. Plants provide many needed products including food, clothing, shelter and fuel. They provide jobs for people who grow them or sell them. They also provide lumber and other materials for homes, are used in medicines, and have even been used as currency. They also provide us with oxygen. Fossil fuels were once growing plants that have been transformed over millions of years.
Plants are capable of making their own food, especially sugar, like glucose.  The chemical equation for this is 6 H20 + 6 CO2 = C6H12O6 + 6 O2. This process is called photosynthesis, but it requires the energy of the sun and a special plant chemical called chlorophyll to occur.
Humans and animals only use a small percentage of all plants. Many are microscopic and live in the ocean. There are so many plants in the world many of them haven’t been discovered yet. So it would be impossible to list or even count every type of plant. Plants live all over the world, but most of them are in the ocean. Plants live in desserts, on mountains, in meadows, in forests, and even in the cities.
People who study plants are called botanists. Botanists do research that benefits agriculture.


Agriculture is the biggest and most important industry in the world. Half of the worlds’ workers are employed in agriculture. It made civilization possible.  Agriculture provides us with many, many things, including lots of food, clothing, paint, and jobs. One of the jobs it provides is farming.
Farming is the commercial use of agriculture to grow plants and animals for food, clothing and lumber. The products used to make clothing are cotton, silk, wool, jute, flax, and sisal.
The food farming provides is land animals, sea animals and plants. 
The land animals include hogs, turkeys, chickens, dairy cattle, beef cattle, goats, and sheep. The sea animals that farming provides are salmon, catfish, trout, oysters and other salt-water shellfish.
The plants farming provides are coco beans, radishes, sweet potatoes, potatoes, sorghum, oats, wheat, barley and rice. Some other plants are rye, millet, oil crops, almost every type of fruit, dry beans, grass, and corn. Other plants include sugar cane, sweet beats, tea, nuts, coffee, tobacco, honey, hay, and soybeans.

Legumes are the second largest family of flowering plants. They get there name from the seed pods that grow off them. There are 14,000 to 17,000 different species of legumes. The main types of legumes are peas, nuts, peanuts, beans, clover, alfalfa and vetch. The sub classes’ legumes include trees, shrubs, herbs, climbing plants and flowers. Legumes are used to make oils, dyes, medicines and timber.

Legumes have a bacteria called rhizobia that live in growths on the roots. These bacteria take in nitrogen from the air and transfer it to the root system. This makes the legumes very valuable to farmers. Farmers often use legumes as “green manure”. This manure helps transform bad soil into usable soil.

Soybeans are very important to agriculture. They supply food for humans and animals. They also provide raw materials for farming. Soybeans are the third largest crop grown in the United States, second only to wheat and corn. More than 75 million acres in the U.S. is dedicated to the growth of soybeans. The United States grows about 40% of the worlds soybeans, growing two and a half billion bushels yearly. More than one third of this is exported to eastern Asia. Other important soybean growers are Brazil, Argentina, China and Ontario. The two states that produce the most soybeans are Illinois and Iowa.

The soybean is an annual. Meaning that it only lives for one year before it has to be replanted. Soybeans are usually planted in the spring. In six to eight weeks small purple or white flowers appear.
Soy has more protein than beef, fish, or eggs. A lot of people decide to eat soy instead of eggs, fish, beef, and chicken. This is because soy is 40% protein while beef, fish and eggs are only 18% protein. Soybeans provide food for humans, animals and raw materials. Soybeans are the largest source of vegetable oil in the world. Soy oil has almost no saturated fat and no cholesterol. Soybeans are in the same family as peas and are sometimes known as soy or soda. People in eastern Asia are the largest consumers of tofu. Tofu is made from soy curd.

Water Pollution
Most water pollution comes from the 400,000 manufacturing companies all around the U.S. They use gallons and gallons of water to wash out many different types of wastes. The water is then washed into the ground, lakes and oceans.

In 1998 the national water quality inventory stated that 45% of the U.S lakes, rivers, streams and ocean shores that were surveyed were polluted so much that you should’t drink it, swim in it, or even fish in it.

Some of the chemicals that were in the polluted lakes, rivers, streams and oceans were phosphates, mercury, asbestos, sulfur, sulfuric acid, nitrate and lead. There were also sodium compounds and petrol chemicals.  In 1986-1990 over 6000 injuries occurred because of chemicals in the water. Another potentially harmful chemical found in water pollution is chlorine.

Chlorine is very poisonous. Chlorine can cause irritation to the throat, nose, lungs and skin. If breathed in it can cause health problems. If a large amount of chlorine is consumed call poison control immediately. It also has a very unpleasant odor. In gas form it is explosive when combined with hydrogen.

Chlorine is also widely used to purify drinking water, since it kills bacteria. It is also used to create paint, petroleum products, medicines and cleaners. Chlorine is also used to make antifreeze, insecticides, paper and plastic.

The gas form of chlorine is made from treating metal sodium with hydrochloric acid. It creates a yellow-greenish gas. When this gas is compressed it creates the liquid form of chlorine. Today the gas is made from passing electric currents through sodium chloride in water. Then the gas is pressurized to form the liquid. In nature chlorine only exists in chloride compounds. Chloride occurs in seawater, salt lakes, and rock salt.

Pure chlorine gas was first created in 1774 by the Swedish chemist Carl Wilhelm Scheele. Scheele treated hydrochloric acid with manganese dioxide and accidentally made chlorine. It wasn’t until 1810 that chlorine was named and identified as a chemical element by Sir Humphrey Davy. Davy named it for the Greek word “chloros” meaning greenish-yellow.

Soybeans are very important plants and are very important to agriculture. Chlorine is very dangerous to plants, animals and people. Water pollution is an ever-present global problem. If something is not done to reduce this problem then it will continue to threaten the environment and possibly the human existence.


Obrecht, Dan “Changing face of water pollution” www.polutionchangeswater/facechange

 “Chlorine” www.blueandgoldfleet.con/html

“Chlorine” 11-5-04


Smith, Aaron “Plants”

“Poly chlorinatedbypenthenols” www.chlorinatedbypenthenols/polution



I would like to thank the following people for helping make my project possible:
∑ My parents for supporting me in all that I have done during this project. Also I would like to thanks them for helping handle the chlorine when I was mixing the solutions.
∑ Mr. Newkirk for explaining things to me when I didn’t understand them. Also for providing a workspace for my research and the tools I needed.
∑ Mrs. Helms for finding helpful facts for my research.
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