Investigating PHOTOSYNTHESIS
hypothesis
By covering the leaves of a Calendula plant in different types of paper, we can change the amount and frequency of light waves allowed to reach the plant, thus changing the amount of photosynthesis. Covering the leaves in black paper will completely block out light and therefore stop photosynthesis completely, covering the leaves in red tinted paper will decrease the amount of photosynthesis allowed.
Materials
black paper
cellophane
calendula plant
test tubes
pipettes
iodine
petri dish
scissors
tape
cellophane
calendula plant
test tubes
pipettes
iodine
petri dish
scissors
tape
procedure
1. Cover leaves in cellophane, black paper, and leave at least one leaf uncovered
2. Wait 48 hours
3. Cut off experimental and control leaves, remove paper
4. place leaves into test tubes
5. Extract chlorophyll by heating
6. Rinse clean in water
7. Place in petri dish
8. Cover with iodine
9. Wait 1 minute, then remove leaf and place on paper towel
10. Observe and record observations
2. Wait 48 hours
3. Cut off experimental and control leaves, remove paper
4. place leaves into test tubes
5. Extract chlorophyll by heating
6. Rinse clean in water
7. Place in petri dish
8. Cover with iodine
9. Wait 1 minute, then remove leaf and place on paper towel
10. Observe and record observations
results
Control - most chlorophyll
Cellophane - less chlorophyll
Black Paper - barely any chlorophyll
Iodine Test: Results Results (1-5)
Control (none) turned light brown 2
Wavelength turned slightly darker brown than the control 4
Intensity turned dark brown 5
Cellophane - less chlorophyll
Black Paper - barely any chlorophyll
Iodine Test: Results Results (1-5)
Control (none) turned light brown 2
Wavelength turned slightly darker brown than the control 4
Intensity turned dark brown 5
conclusion and reflection
In this lab we learned how the intensity and wavelength of light affects photosynthesis in plants. We did this through a series of experiments using iodine to test for products of the process of photosynthesis. We learned through these experiments that the black paper greatly decreases photosynthesis and the cellophane also reduces photosynthesis through filtering light. I learned a lot in this lab not only about light and photosynthesis, but also about how to work together and how to conduct our own experiments.