Photosynthesis lab
purpose:
The purpose of this lab was to determine how the intensity and wavelength of light affect photosynthesis.
Hypothesis:
If the light is more intense, the more starch will be produced. Changing the wavelength will result in less starch because red wavelengths of light are absorbed in the plant, but the red light is filtered out using the red cellophane.
MATERIALS:
2 Plants
Red Cellophane
Test Tubes
Scissors
Lugol's Iodine
Black Paper
Tape
Petri Dish
Paper Towels
Tweezers
Red Cellophane
Test Tubes
Scissors
Lugol's Iodine
Black Paper
Tape
Petri Dish
Paper Towels
Tweezers
procedure:
1. Form a hypothesis about how the manipulation of variables will affect photosynthesis. Give reasoning.
2. Cover leaves with either black paper or red cellophane. Leave some leaves for control.
3. Wait one day for photosynthesis to occur.
4. Cut-off experimental and control leaves.
5. Extract chlorophyll with hot alcohol.
6. Rinse in water and place in petri dish.
7. Cover with iodine.
8. After a minute, remove and place on towel. Record color with assigned scale of (0-5).
2. Cover leaves with either black paper or red cellophane. Leave some leaves for control.
3. Wait one day for photosynthesis to occur.
4. Cut-off experimental and control leaves.
5. Extract chlorophyll with hot alcohol.
6. Rinse in water and place in petri dish.
7. Cover with iodine.
8. After a minute, remove and place on towel. Record color with assigned scale of (0-5).
Data/results:
Plants Black Cover Red cover Control
Calendula 5 3 2
Coleus N/A 4 3
Calendula 5 3 2
Coleus N/A 4 3
Data/analysis:
Our results disproved our hypothesis. The plant leaves that were covered by the red filter photosynthesized more than the control leaf, and the leaf covered in the black paper photosynthesized most of all. Although these were the results, they might have been invalid and therefore unusable. We know that this is inaccurate because common sense says that the black leaf should have photosynthesized the least, having not received much sunlight at all. The order should have been black cover < red filter < control in terms of starch produced during photosynthesis. These invalid results could have been due to mislabeling, incorrect procedure, or just being unorganized.
reflection:
This lab was fun and a nice break from notes and lectures. However, things could have gone a lot better. Our group was unorganized, unfocused, and the workload was distributed unevenly. In future projects, we could focus more on the task at hand before goofing off.