The problem was to find the effect of water impurities on plant growth. Each plant will be watered with sugar, salt, bleach, or water. Which water impurity will effect the plant's growth? How will each water impurity effect the plant's growth?

To do this experiment, one plant has to be watered with 157.6 milliliters of water, another watered with 157.6 milliliters of a sugar and water solution, the third plant has to be watered with 157.6 milliliters of a salt and water solution, and the fourth plant has to be watered with 157.6 milliliters of a bleach and water solution. The plants were watered on Thursday and Sunday, and measured on Friday and Monday. Each plant had a stem marked off that would be measured using string and a ruler. The heights were recorded and the experiment ran for four weeks.

The conclusions for this experiment are that the plant watered with sugar grew the most, while the plant watered with water grew a little less. The plant watered with salt grew even less, and the plant watered with bleach grew the least. The heights of each plant changed by going up or down. No matter what substance was used to water the plant, it had to be mixed into water. Otherwise it wouldn't dissolve into the soil.
 
 

What is the effect of water impurities on plant growth?
 
 

If a plant is watered with sugar, then it will grow the most.
 
 

This experiment is "The effect of water impurities on the growth of plants." It will determine the effect of sugar, salt, and chlorine on the growth of a plant. Which water impurity will effect a plants growth? Will each substance used effect the rate of the plants growth differently?

There are two types of plants, a flowering plant (which produces flowers), and a nonflowering plant (such as mosses, ferns, and horsetails). During daylight hours, the plant collects the suns energy. During the night, is when the plant works. The plant uses the suns energy to make food, which is in the form of sugars. The food then has to be transported to where it is needed, while water and minerals from the soil have to be carried away to the stems, branches, and leaves of the plant (Burnie, 1989).

Green plants are the only plants that produce oxygen and make food. Photosynthesis is the process of the suns energy being turned into food. Photosynthesis takes place in chloroplasts. Chloroplasts contain chlorophyll, which absorb sunlight. The green plants use the sunlight to combine carbon dioxide and water to make sugar and oxygen. These plants use the sugar made to make starch, fats, and proteins (http://tqjunior.advanced.org/3715/photo3.html).

A seed has one embryo inside of it. The root begins to grow first. The pressure from the growing root tip breaks open the seed coat at that end of the seed. Then the growing root can emerge. The root produces fine hairs that help it absorb water. The hypocotyl is the part of the seedling that emerges going upward. A peg grows as a brace against the seed coat. The hypocotyl itself grows upward. The cotyledon, which is a part of the hypocotyl, opens and reveals the first leaves. The stem will continue to grow revealing more leaves (Rahn, 1978).

Plants produce hormones, which are the main factors controlling growth and development. They are produced in one part of the plant and transported to another part. Each hormone has a different effect depending on where the tissue it goes to is (Schraer and Stoltze, 1999). An example of the most important plant hormone is auxin. Growing stem tips produce it, and in other areas it is transported to, it could promote growth or stop growth. It also slows down the abscission (dropping off) of flowers, fruits, and leaves (Microsoft Encarta '97 Encyclopedia, 1993-1996).
 
 

The purpose of this experiment was to determine the effect of water impurities on the growth of plants. Each plant was put near a big window that let in a lot of sun. Two different stems from each plant were marked with bag ties. The height of the two stems from each plant were measured. The plants were watered with 157.6 milliliters of the solution. Each plant was watered on Thursday and Sunday. The first solution contained six milliliters of Clorox bleach and 151.6 milliliters of water. The second solution contained 6 grams of sugar and 157.6 milliliters of water. The third solution contained 6 grams of salt and 157.6 milliliters of water. On Friday and Monday the height of the stems of each plant were measured, and the height was recorded. There was also a plant that was watered just with water, for the control setup. This experiment ran for four weeks. The data was analyzed to determine which plant grew the most over that period of four weeks.
 
 

The experiment was "The effect of water impurities on plant growth." The results of the plant watered with water were that it grew by one centimeter from the first to fifth day, its height went down by one fourth of a centimeter from the fifth to eighth day, its height was the same from the eighth to twelfth day, and it grew by three fourths of a centimeter from the twelfth to fifteenth day. The plants height stayed the same from the fifteenth to the twenty-ninth day. The second plant watered with sugar grew one centimeter from the first to fifth day, it grew one fourth of a centimeter from the fifth to eighth day, its height stayed the same from the eighth to twelfth day, and its height went down one fourth of a centimeter from the twelfth to fifteenth day. The plant grew one fourth of a centimeter from the fifteenth to nineteenth day, its height went down by one centimeter from the nineteenth to the twenty-second day, its height went down by one fourth of a centimeter from the twenty-second to the twenty-sixth day, and it grew one fourth of a centimeter from the twenty-sixth to the twenty-ninth day.

The third plant watered with salt grew one and one fourth of a centimeter from the first to fifth day, its height went down by half of a centimeter from the fifth to eighth day, it grew half of a centimeter from the eighth to twelfth day, and the plants height stayed the same from the twelfth to the nineteenth day. The plant grew half a centimeter from the nineteenth to the twenty-second day, and its height went down by half of a centimeter from the twenty-second to the twenty-ninth day. The fourth plants height, watered with bleach, went down by one fourth of a centimeter from the first to fifth day, its height stayed the same from the fifth to the twelfth day, and its height went down by one fourth of a centimeter from the twelfth to fifteenth day. The plants height went down by one fourth of a centimeter from the fifteenth to the nineteenth day, its height went down by one centimeter from the nineteenth to the twenty-second day, its height went down by one fourth of a centimeter from the twenty-second to the twenty-sixth day, and the plant grew half of a centimeter from the twenty-sixth to the twenty-ninth day. For visual results look at Figure 1.
 

The experiment was "The effect of water impurities on plant growth." Some relationships were discovered. One was that as time went on, the plants heights in some way changed (either it went up or down). No matter what the plants were watered with it had to be mixed into water so it could go into the soil and get to the plants roots. Information already known are that plants need to be watered with some kind of liquid, and the plants should be growing, and their height probably shouldn't be going down.

The conclusion was that the plant watered with sugar was the plant that grew the most, overall. This is the conclusion because anything usable that plants take in are turned into a form of sugar. The plant watered with sugar in the water was already taking in sugar so it didn't have to convert as many substances to a form of sugar. This conclusion was arrived at by looking at the data and figuring out during what days of measurements each plants height went down or up, and by how much. The plant watered with sugar grew the most times (and grew the highest amount overall) in between the measurements taken. That is why that plant was the best result of the experiment.

There is a loophole (mistake) in the results. The measurements taken might not be exact because a string was put along a stem and marked off at the point it touched the top of the stem. Then that section of the string was measured to see how long the stem was. The string mightve not been marked off right or it wasn't put against the ruler right, and that could have made the results inaccurate. This mistake could be fixed by measuring the same way as mentioned above, but doing it a few times to be sure of the height, or to use some kind of a tape measure to put directly along the stem, so the height can be found immediately and the tape measure could bend like the stem does.
 
 

The conclusions of this experiment are that the plant watered with sugar grew the most. Another conclusion is that the control (the plant watered with water) grew a little less than the plant watered with sugar. The plant watered with salt grew a little less than the control, and the plant watered with bleach grew the least amount. The reason that was discovered for why the plant watered with sugar grew the most was because when plants absorb nutrients, they turn them into some form of sugar. This plant didn't have to do that because it was already absorbing sugar. The other substances, except water, probably just stopped the plants from growing as much.
 
 

The next project to expand on the experiment that results in the effect of water impurities on the growth of plants might be to use more water impurities. There could also be a bigger variety of water impurities. The plants used would still all be the same exact kind, but more of those plants would have to be bought. More research would have to be done because there would have to be more reasons (because more water impurities are being used) for why some water impurities didn't help the plants grow. This research would also include why some water impurities did help the plants grow. Besides more research and the bigger varieties of substances used to water the plants, the experiment would be done the same way.
 
 

Burnie, David. Plant. New York: Alfred A. Knopf, Inc., 1989.

"Photosynthesis." http://tqjunior.advanced.org/3715/photo3.html. America Online, 1997.

"Plant." Encarta Encyclopedia. Microsoft, 1997.

Rahn, Joan Elma. Watch It Grow. Watch It Change. Canada: McClelland & Stewart, Ltd., 1978.

Schraer, William D. Biology-The Study Of Life. New Jersey: Prentice Hall, Inc., 1999.
 

Return to Top of "Exemplary Science Fair Project"
Return to Biology : An Internet Sourcebook for Science Fair Projects Homepage