ScienceFair

Abstract
My question is which aquatic plant is best at recycling carbon dioxide into oxygen. I think Egeria Densa will be best at photosynthesis because it is the best known, most commonly used in aquariums, and is constantly used in experiments to demonstrate oxygen evolution. I will attempt to solve my problem by testing three different aquatic plants and comparing the average amount of oxygen produced by each type of plant.
I learned about the characteristics and history of plants, oxygen, carbon dioxide, photosynthesis, respiration, light, baking soda, and methods of measuring oxygen produced in photosynthesis. In my experiment I place one plant of each plant type that are the same length, width, and mass into an inverted graduated cylinder filled with a NaHCO3 solution with the plant's tip closest to the bottom of the graduated cylinder. Oxygen production was measured after three hours and was determined by the decrease in water level in the graduated cylinder. I think the average amount of oxygen produced by Egeria Densa will be largest.
My data lead to the conclusion that Cambomba Carolina was the aquatic plant that could recycle carbon dioxide into oxygen best. Cambomba Carolina produced an average of 3.3 milliliters of oxygen, which is 0.3 more then the average amount of oxygen produced by Rotala Indica and 0.4 more then the average amount of oxygen produced by Egeria Densa.

Acknowledgements
I would like to thank the following people for guiding and helping me through science fair. I would like to thank my science teacher, Ms. Buchanan, for helping me when I was frustrated, teaching me a lot about science, providing feedback, lending materials, and guiding me. Mr. Mendibles for providing ideas on his own free time and giving me the basis of my experiment. I would like to thank Mr. Carroll for helping me get research, write my research paper, and editing it. Mr. Negus for helping when I needed it, providing valuable feedback, and for being so dedicated to sciences fair. My classmates for providing valuable feedback, helping me, and making science fair a fun experience. Michael, Luciano, and Jordan for keeping "Moodle" working so we could use it. Mrs. Jones for teaching me much about science, opening my interest about plants, and lending me materials. I would like to thank my Mom for taking the time to buy materials for me, my brother for taking his time from his Thanksgiving vacation to help me with my experiment, and my entire family for providing support when I needed it most.
Thank you so much everyone!

Statement of the Problem
I am attempting to solve the problem of which aquatic plant can photosynthesize best. I want to know which aquatic plant is best at photosynthesis. If I found out which aquatic plant can photosynthesize best, it could be used in the future to possibly help with global warming. If we needed a way to reverse or lessen global warming, photosynthesis could help. This is an example of how knowing the answer to my problem can benefit people.
I am going to solve this problem by testing the different aquatic plants and finding out which one can photosynthesize best. I must do the same experiment every time to ensure that I obtain accurate results. I will calculate the mass of the plants with a mass balance to make sure the mass of the plants are the same, and then I will setup my experiment. I will wait two hours and then measure the amount of oxygen produced by each plant. I am controlling the type of plant and the amount of time they have to photosynthesize.

Review of Literature
see seperate page

Hypothesis
My hypothesis is that the Egeria Densa (elodea) will photosynthesize best. I think this because based on information obtained through research, Egeria Densa is the best known, most commonly used aquarium plant, adaptable, and is constantly used in experiments to demonstrate oxygen evolution.

Materials
¬ 1 running watch
¬ Tap water
¬ 9 100ml clear graduated cylinders
¬ 3 Egeria Densa plants
¬ 3 Rotala Indica plants
¬ 3 Cambomba Carolina plants
¬ 1 clear plastic tub
¬ 2 100-watt 120-volt clamp lights
¬ Baking Soda
¬ 1 Teaspoon
¬ 1-liter water bottle
¬ Duct tape
¬ 1 Electronic mass balance
¬ 9 Clear cups
¬ 9 Clear cups with drain holes
¬ 1 thermometer with Celsius increments

Procedure
Part I: Measuring Plant Mass, Height, and Width
1. Place a dry, clear cup with drain holes in a clear cup without holes.
2. Label the stacked cups with the number 1.
3. Below the number label it "Egeria Densa".
4. Carefully pick up an Egeria Densa plant and place it in the top cup with drain holes.
5. Let the excess water drip for 1 minute.
6. Place they the stacked cups with the plant and water on the mass balance.
7. Record the total mass in the first column, next to number 1 on in the table in the notebook labeled "Mass of cups, water, and plants".
8. Remove the plant from the top cup and place on a dry paper towel.
9. Now record the mass of the stacked cups and water in the second column, next to number 1, in the table in the notebook labeled "Mass of cups and water".
10. Subtract the number from the from the second column from the first to get the mass of the plant.
11. Record that answer in the third column, next to number one, in the table in the notebook labeled "Mass of plant".
12. Repeat steps 1 through 11 three times for every Egeria Densa plant, each time make sure to use dry cups and to increase the number on the label by one. (and to record it in the right column and row in the right table).
13. Repeat steps 1 through 11 three times for every Rotala Indica plant, each time make sure to use dry cups and to increase the number on the label by one. (also to record the information in the right column and row in the right table).
14. Repeat steps 1 through 11 three times for every Cambomba Carolina plant, each time make sure to use dry cups and to increase the number on the label by one. (also to record the information in the right column and row in the right table).
15. Once all the plants have been measured choose the plant out of ALL the plants, with the least mass.
16. Trim the others until they have the same mass using the same technique as before (refer to steps 1 through 10 except this time record your data in column four, five, etc... in the notebook labeled 2nd time, third time, etc... and the last column should be labeled " Mass of plant-Final" and make sure they are all the same).
17. Measure and record the plants height and width in centimeters.
18. Trim all the plants until they are the same. (Width can vary from 1 1/2-2 cm).
Note: Plants can be trimmed, very carefully, at the tips of the leaves, stem, or roots.
Part II: Conducting the experiment
1. Using a one-liter water bottle, fill the clear plastic tub halfway with tap water.
2. Add one teaspoon of baking powder for each liter of tap water (to act as a source of carbon dioxide).
3. Measure the temperature with the thermometer, make sure the temperature is between 180-250C. If not, add cold or warm water until it is (make sure step 2 is constant).
4. Place two clamp lights side by side with 100-watt light bulbs side by on the rim of the plastic tub.
5. Place a graduated cylinder under water so that the graduated cylinder is horizontal and fill it 9/10 of the way with water.
6. Place the graduated cylinder outside the plastic bin, with the graduated cylinder bottom on solid ground.
7. Repeat step 5 and 6 for all nine cylinders.
8. Place an Egeria Densa plant inside a graduated cylinder with the end of the stem (the tip of the plant) closest to the bottom of the graduated cylinder.
9. Repeat step 8 for all three Egeria Densa plants (make sure to only place one plant in each graduated cylinder).
10. Repeat step 8 for all three Rotala Indica plants (make sure to only place one plant in each graduated cylinder).
11. Repeat step 8 for all three Cambomba Carolina plants(make sure to only place one plant in each graduated cylinder).
12. Carefully, one-by-one, take each graduated cylinder and invert it in the clear plastic tub filled with water so that all the cylinders are in a straight line.
13. Arrange the graduated cylinders without lifting them out of the water, so that the left most graduated cylinder contains an Egeria Densa plant, the second left most contains a Rotala Indica plant, and the 3rd left most contains a Cambomba Carolina plant. Repeat this pattern through out.
14. Let each graduated cylinder stand straight (not leaning on the rim of the clear plastic tub), with the opening of the graduated cylinder firmly on the bottom of the clear plastic tub.
15. Adjust the water by letting water drip out or add water until the water level is stable at an increment on the graduated cylinder.
16. Place a post-it-note on the side of clear plastic tub for each cylinder.
17. Number each post-it-note next to a graduated cylinder containing an Egeria Densa plant with a number. Starting at the left side and beginning with the number one. Work to the right until all post-it-notes next to an Egeria Densa plant are numbered.
18. Number each post-it-note next to a graduated cylinder containing an Rotala Indica plant with a number. Starting at the left side and beginning with the number one. Work to the right until all post-it-notes next to an Rotala Indica plant are numbered.
19. Number each post-it-note next to a graduated cylinder containing an Cambomba Carolina plant with a number. Starting at the left side and beginning with the number one. Work to the right until all post-it-notes next to an Cambomba Carolina plant are numbered.
20. Record the what the water level is for each Egeria Densa plant on the left side of each of the "Egeria Densa" column and draw an arrow pointing to the right next to the number (take care to record the in the correct plant column and for the correct plant. The cylinder numbered one should be the topmost, number 2 on row down, and number three the third row down ).
21. Repeat step 20 for all three Rotala Indica plants(take care to record the in the correct plant column and for the correct plant. The cylinder numbered one should be the topmost, number 2 on row down, and number three the third row down ).
22. Repeat step 20 for all three Cambomba Carolina plants (take care to record the in the correct plant column and for the correct plant. The cylinder numbered one should be the topmost, number 2 on row down, and number three the third row down ).
23. Place a piece of duct tape on the graduated cylinder bottom (the part of the graduated cylinder not submerged) and attach it to the side of the tub.
24. Repeat steps 17 for all the graduated cylinders.
25. Turn on the two 100 watt clamp lights.
26. Using a running watch, let 3 hours elapse.
27. Record data by writing what the water level of each graduated cylinder is next to the previously drawn arrow. Subtract number on the right side of the arrow from the number on the left side of the arrow in order to get the amount of oxygen produced. Record that number.
28. Repeat experiment until all data is collected.
Data

Results

Summary Statement
This graph shows the average amount of oxygen produced by each aquatic plant. The independent variable is the type of aquatic plant. The dependent variable is the amount of oxygen is produced. The data ranged from zero to 12 milliliters. Egeria Densa produced an average of 2.9 milliliters of oxygen, Rotala Indica produced an average of 3 milliliters of oxygen, and Cambomba Carolina produced an average of 3.3 milliliters of oxygen. This data leads to the answer of my question, that Cambomba Carolina is the best aquatic plant at recycling carbon dioxide into oxygen.

Conclusion
In order to answer the question of which aquatic plant can recycle carbon dioxide into oxygen most efficiently, measuring oxygen production by each aquatic plant was necessary. Measuring oxygen production was done by placing each aquatic plant, with the tip closest to the bottom of the graduated cylinder, inside an inverted graduated cylinder filled with a NaHCO3 solution (a solution of 1 teaspoon of baking soda per liter of water). Oxygen production was measured after three hours and was determined by the decrease in water level in the graduated cylinder. The independent variable is the type of aquatic plant. The dependent variable is the amount of oxygen that is produced.
The data collected leads to the answer of my question, that Cambomba Carolina is the best aquatic plant at recycling carbon dioxide into oxygen. Cambomba Carolina produced an average of 3.3 milliliters of oxygen, which is 0.3 more then the average amount of oxygen produced by Rotala Indica and 0.4 more then the average amount of oxygen produced by Egeria Densa. This data shows that my original hypothesis, that Egeria Densa would do best, is incorrect.
The results of the experiment were unanticipated because Egeria Densa was expected to have the best results. Some unresolved questions are if the readings were accurate enough and if all the variables were controlled. If this experiment were to be repeated things such as a method of measurement with more accuracy, and independent variable would be changed, more trials would be done and the variables would be more controlled. Changes such as light source, materials, and methods were made to the procedure many times before the experiment produced any results. Recommendations for future tests is to plan ahead and to test perhaps more plants and have more different plants to compare.

Aquatic plants inside an inverted graduated cylinder filled with sodium bicarbonate. The plants are in the process of photosynthesis and are recieving light from the 100 watt-120 volt clamp lights.