1. By James Casieri, Claire Wille, and Evan Kuehnert
PLANTING SCIENCE
By James Casieri, Claire Wille, and Evan Kuehnert

2. Question
How does the pH of a plant’s environment impact the process of photosynthesis?

3. Hypothesis
We hypothesized that the less drops of acidic or basic compounds added to the  water-soap solution, the faster photosynthesis would occur because in prior experiments with enzymes, the H+ ions in acids and OH- ions in bases interfered with the reaction.

4. Materials Spinach Leaves Carbonated Water (300mL) Syringe HCl (Acid)
NaOH (Base)
Soap
Water
Hole Puncher
Timer
Beakers (3)

5. Procedure Gather Materials Create 14 leaf disks for each solution
Pour 100mL of carbonated water into each beaker
Put enough drops of acid in one beaker to make the solution 4 pH
Put enough drops of base in one beaker to make the solution 10 pH
Leave the third beaker neutral
Add soap to a separate beaker
Put 14 leaf disks in the syringe and fill it with the water-soap solution
Create a vacuum by placing thumb over the top and pull down for 10 seconds; repeat until all the disks sink
Do steps 8 and 9 three times

6. Procedure (Continued)
11. Put the disks into each beaker, each beaker should receive 14 disks
12. Record number of floating disks every 30 seconds

7. Control Group
Our control group was a neutral (pH 7) solution

8. Data Time Neutral Acid 0:00 3 0:30 1:00 4 7 1:30 5 11 2:00 12 2:30 613
3:00 14
3:30
4:00 8
4:30 9
5:00 9 14
5:30
6:00
6:30
7:00
7:30
8:00
8:30 11
9:00
9:30
10:00

9. Graph

10. Analysis
The data clearly demonstrates that the acidic solution is the ideal environment for photosynthesis.
The pH of the acidic solution (which was 10) must be either close to or the same as the optimal pH of the spinach plant leaves.
After further research, the drastic increase in the speed in which photosynthesis transpired in the acidic solution is because the optimal pH of the enzymes responsible for breaking up electrons in water molecules to create hydrogen ions and oxygen gas must have been at or around the pH of the acidic solution, thus causing the leaf disks to rise faster.

11. Sources of Error
Some leaf disks may have been damaged to the point that they would not float
Some leaf disks may have been prepared improperly, causing them to float to the top without the help of photosynthesis.
Never could conduct experiment with basic solution, for the NaOH compound reacted to the carbon dioxide in the carbonated water.

12. Conclusion
Based on the results of our experiment, we have concluded that an acidic environment is best for photosynthesis in spinach leaves, contradictory to our hypothesis that a neutral pH would be the ideal environment. However, this is not necessarily the case for all plants; some have an optimal pH higher or lower (more often the latter) than that of the spinach plant. Thus, the results of this experiment do not apply across the board, but rather only pertain to spinach leaves. To sum up, the ideal environment for photosynthesis in spinach leaves is an acidic one.