Photosynthetic Effect Lab
Purpose/Hypothesis: Effect of intensity and wavelength of light on photosynthesis (measured by amount of starch production).
If the cellophane is covering the leaves, they will barely be lighter because it is reflecting red light. If the black paper is covering the leaves, it will have a dramatic loss of color because black reflects all colors letting no light in. The wavelength will affect the color of the plant (see Absorbance Spectrum of Chlorophyll A + B), and the intensity of light will affect the physical state of the leaf (dead or alive).
Materials List:
Procedure:
Day 1 - covered 3 leaves with black paper and 3 leaves with red cellophane
Day 2 - removed leaves, removed chlorophyll be heating leaves in hot Ethanol (E + OH)
- rinse
- test for starch using iodine
- for colored plants, separate red from green leaves and test separately
Results:
Purpose/Hypothesis: Effect of intensity and wavelength of light on photosynthesis (measured by amount of starch production).
If the cellophane is covering the leaves, they will barely be lighter because it is reflecting red light. If the black paper is covering the leaves, it will have a dramatic loss of color because black reflects all colors letting no light in. The wavelength will affect the color of the plant (see Absorbance Spectrum of Chlorophyll A + B), and the intensity of light will affect the physical state of the leaf (dead or alive).
Materials List:
- 5 test tubes
- 400-mL beaker
- scissors
- 5 petri dishes
- tape - scotch and masking
- tweezers
- dropper
- blue cellophane
- green cellophane
- red cellophane
- black paper
- black wax pencil
- spatula
- iodine solution
- hot E + OH
- Coleus plant - green
- Coleus plant - red
- paper towels
- water
Procedure:
Day 1 - covered 3 leaves with black paper and 3 leaves with red cellophane
Day 2 - removed leaves, removed chlorophyll be heating leaves in hot Ethanol (E + OH)
- rinse
- test for starch using iodine
- for colored plants, separate red from green leaves and test separately
Results:
Data Observations:
Data Analysis/Conclusion:
Reflection:
1. The most interesting part of this lab was seeing how plants react to different colors, or wavelengths, of light. I was amazed how the red cellophane had no effect on photosynthesis, but after thinking about it logically, it made sense. With red cellophane over the leaf, red light was reflected. Chlorophyll doesn't need red light for photosynthesis. The chlorophyll only absorbs the green and blue light. Also, on the chlorophyll spectrum, red light has no impact on photosynthesis, negative or positive. therefore, a plant could not survive in just red light. Another fascinating part of the lab was learning about Chlorophyll A and Chlorophyll B. Chlorophyll A absorbs green light in green plants, while Chlorophyll B absorbs red light in red plants. When chlorophyll A breaks down from the different wavelengths of light in the fall, we see color like red (anthocyanin), orange (carotenoid), and brown (tannin).
2. Next time we do this lab, I would like to see the effect on different types of plants. We only used the green and red Coleus plants, but maybe different species of plants would react differently from the lack of different wavelengths of light. Testing with even more colors covering the plant could be exciting as well. This would all be great, but it would be more time consuming and expensive to provide each group with a different plant.
3. I worked with Mikayla DeBarros as my partner, and two others in this experiment. I'd give Mikayla a 19 in leadership, a 20 in cooperation, 20 in attitude and demeanor, a 19 in facilitation and mediation, and a 19 in empathy. Like our other projects we work well together and both give instructions to each other, and listen to each other. We aren't always the most positive about the test but we work together to solve the problem. Mikayla always responds to the things I say like bringing an extra test tube or covering one of the leaves. Lastly, we are jokingly not the most respectful to each other, but when things are serious, we are kind to each other. One of the best part of this year is having one of my good friends to work with. You grow more appreciation for the other person, even if it means bickering a little. The other two people we worked with didn't collaborate with us as well. Most of the time they would either contribute nothing, or want to do it all themselves. In the future, I wish that I could be with people who are comfortable in a group setting, like Mikayla.
1. The most interesting part of this lab was seeing how plants react to different colors, or wavelengths, of light. I was amazed how the red cellophane had no effect on photosynthesis, but after thinking about it logically, it made sense. With red cellophane over the leaf, red light was reflected. Chlorophyll doesn't need red light for photosynthesis. The chlorophyll only absorbs the green and blue light. Also, on the chlorophyll spectrum, red light has no impact on photosynthesis, negative or positive. therefore, a plant could not survive in just red light. Another fascinating part of the lab was learning about Chlorophyll A and Chlorophyll B. Chlorophyll A absorbs green light in green plants, while Chlorophyll B absorbs red light in red plants. When chlorophyll A breaks down from the different wavelengths of light in the fall, we see color like red (anthocyanin), orange (carotenoid), and brown (tannin).
2. Next time we do this lab, I would like to see the effect on different types of plants. We only used the green and red Coleus plants, but maybe different species of plants would react differently from the lack of different wavelengths of light. Testing with even more colors covering the plant could be exciting as well. This would all be great, but it would be more time consuming and expensive to provide each group with a different plant.
3. I worked with Mikayla DeBarros as my partner, and two others in this experiment. I'd give Mikayla a 19 in leadership, a 20 in cooperation, 20 in attitude and demeanor, a 19 in facilitation and mediation, and a 19 in empathy. Like our other projects we work well together and both give instructions to each other, and listen to each other. We aren't always the most positive about the test but we work together to solve the problem. Mikayla always responds to the things I say like bringing an extra test tube or covering one of the leaves. Lastly, we are jokingly not the most respectful to each other, but when things are serious, we are kind to each other. One of the best part of this year is having one of my good friends to work with. You grow more appreciation for the other person, even if it means bickering a little. The other two people we worked with didn't collaborate with us as well. Most of the time they would either contribute nothing, or want to do it all themselves. In the future, I wish that I could be with people who are comfortable in a group setting, like Mikayla.