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Photosynthesis Lab Report50nm. When the spectrophotometer was set to 400nm, it was blanked and the respective pigmentwas inserted. The wavelength was then increased by 50nm, the spectrophotometer was once again blanked and the pigment was recorded again. This process was continued until the absorption was recorded at 700nm and repeated for the other pigments. RESULTSLight IntensityAbsorbance values indicated photochemical reaction rate in the different test tubes. The negative control variable was able to show the result of the slowest absorption rate. The results of the tubeplaced 24cm away from the light showed a fluctuating absorption rate. The tube 30cm away showed the fastest rate of absorption and the tube furthest away at 49cm showed the slowest rate of absorption. The tube the furthest away was not able to absorb enough light and this resulted in a slower rate of photosynthesis. (Table 7-3)ColorThe positive control placed in white light had all of the leaf disks floating within 15 minutes because the disks were exposed to all light spectrums. The negative control was placed in the dark and showed no disks floating at the end of the 30-minute testing period. The blue light was the most effective in the disks photosynthesizing and the green light was the least effective and showed no disks floating at all. The disks placed in the green light box were ineffective in producing oxygen, floating in this case, because they reflect the green light rather than absorbingit. The red light allowed the disks to float, but at a slower rate than the blue. (Table 7-4) WavelengthThe observed data for showed that the pigments did not absorb the very much light at a wavelength of 450nm which is a green spectrum. This is because green is reflected. The different4
Kelley WardBIOL-111-508Photosynthesis Lab Reportpigments showed varying increases and decreases in absorption through different wavelengths. The light intensity at the blue spectrum was the highest and varied depending on pigment for the other wavelengths. (Table 7-6)DISCUSSIONLight IntensityAs light intensity increased (when the test tube was closer to the light source), typically the absorption levels would have increased. However, in this experiment, the test tube placed 24cm away from the light was too close to effectively allow the chloroplasts to photosynthesize. The light source was too strong and caused the chloroplasts to die. The tube placed 30 cm away was at a perfect spot where it could effectively absorb the light. Therefore, my hypothesis was incorrect. The results of the test tube wrapped in the foil also may have been skewed due to light exposure when it was placed in the spectrophotometer. ColorThe beaker placed in the green light box did not photosynthesize because the green plant reflected green light. The leaf disks favored the blue light environment because they sometimes use blue light in photosynthesis. My hypothesis was correct because the beaker placed in the bluecolor box had the highest rate of photosynthesis. These results may have been affected by the