Photosynthesis Lab
Purpose
The purpose of this lab is to test if different wavelength and intensity of light affect the plant's ability to complete photosynthesis.
Hypothesis
We think that starch will be most abundant in the uncovered leaves, then then cellophane covered leaves, and then lastly the completely covered leaves. The uncovered leaves will get more intense light waves and will produce more chlorophyll. The cellophane covered leaves will change the light waves and reflect some of the light waves back. The covered leaves will receive no light and therefore be a lighter green because it did not produce any chlorophyll.
Materials
The purpose of this lab is to test if different wavelength and intensity of light affect the plant's ability to complete photosynthesis.
Hypothesis
We think that starch will be most abundant in the uncovered leaves, then then cellophane covered leaves, and then lastly the completely covered leaves. The uncovered leaves will get more intense light waves and will produce more chlorophyll. The cellophane covered leaves will change the light waves and reflect some of the light waves back. The covered leaves will receive no light and therefore be a lighter green because it did not produce any chlorophyll.
Materials
Iodine
coleus plant - red coleus plant - green pipet spatula |
5 vials
black construction paper red or blue cellophane tape water |
5 petry dishes
China marker paper towels scissors tweezers |
Procedure
1. Form a hypothosis
2. Cover some of the coleus plant leaves with black paper and red or blue cellophane. Leave for a day.
3. Cut off the expiremental leaves and put them into vials.
4. Extract chlorophyll by placing vials into boiling water and alcohol.
5. Rinse off the expiremental leaves with water.
6. Place leaves in a petry dish and cover with iodine. Wait 1 minute and then place leaves on a paper towel.
7. Record the results in a data table by giving numbers to describe the coloring of the leaf. The coloration will tell you if starch is present in the leaf.
1. Form a hypothosis
2. Cover some of the coleus plant leaves with black paper and red or blue cellophane. Leave for a day.
3. Cut off the expiremental leaves and put them into vials.
4. Extract chlorophyll by placing vials into boiling water and alcohol.
5. Rinse off the expiremental leaves with water.
6. Place leaves in a petry dish and cover with iodine. Wait 1 minute and then place leaves on a paper towel.
7. Record the results in a data table by giving numbers to describe the coloring of the leaf. The coloration will tell you if starch is present in the leaf.
Data Results
Below is a data table showing observations and the coloring of the leafs. Our scale is a scale of 3 with 1 being light colored and weak positive to 3 being dark and strong positive.
Leaf
Covered (black paper) Covered (red cellophane) Uncovered Covered red leaf (red cellophane) Uncovered red leaf |
Strength of Test (color)
1 3 2 2.5 2 |
Observations
It was a light brown color. dark brown; almost black dark green/brown dark but not extremely dark a brownish color |
Conclusion
From the data that we recorded, I can conclude that leaves covered in red cellophane produced the most starch. After that, the uncovered leaves conatined the next highest amount of starch. Finally, the covered leaves had the least amount of starch. The leaves covered in the red cellophane created more photosynthesis than the uncovered leaves and covered leaves. These results were somewhat of a suprise for us. Everybody in our group thought that the uncovered leaves would have the most starch because they were always in the sunlight. It
Reflection
1. What did you like/find interesting?
I found it interesting that the leaves that were covered by cellophane produced more starch than the uncovered leaves. I though that the red cellophane would reflect some light back and therefore the leaves would produce less starch. I think that this data might be a little off because it does not seem logical, but it is what our results got us. The only reason that I can think of that allows the cellophane covered leaves to photosynthesize more is that the cellophane increased the intensity of the light waves. I also liked the chlorophyll extraction and seeing clear leaves.
2. How did you and your partner collaborate?
I was in a group with Toran, Kyle, Austin, Logan, Jason, Andrew, and me. We work together well as a large group and because we were always doing something. Everybody contributed to the success of the project and we were able to complete the project quickly. Data analysis went smoothly because we all collaborated to find the answer to the problem. Through collaboration, we found the most accurate data that we could possibly find.
3. What would you do differently next time?
Next time, I would want to analyze the leaves for starch again. Andrew accidently dumped too much iodine on the leaves and I think that that could have altered our data. I also would like to test for the other macromolecules in the leaves. I think that it would be interesting to see what is inside of the leaves and what they are made of.
I found it interesting that the leaves that were covered by cellophane produced more starch than the uncovered leaves. I though that the red cellophane would reflect some light back and therefore the leaves would produce less starch. I think that this data might be a little off because it does not seem logical, but it is what our results got us. The only reason that I can think of that allows the cellophane covered leaves to photosynthesize more is that the cellophane increased the intensity of the light waves. I also liked the chlorophyll extraction and seeing clear leaves.
2. How did you and your partner collaborate?
I was in a group with Toran, Kyle, Austin, Logan, Jason, Andrew, and me. We work together well as a large group and because we were always doing something. Everybody contributed to the success of the project and we were able to complete the project quickly. Data analysis went smoothly because we all collaborated to find the answer to the problem. Through collaboration, we found the most accurate data that we could possibly find.
3. What would you do differently next time?
Next time, I would want to analyze the leaves for starch again. Andrew accidently dumped too much iodine on the leaves and I think that that could have altered our data. I also would like to test for the other macromolecules in the leaves. I think that it would be interesting to see what is inside of the leaves and what they are made of.