Photosynthesis Lab

Background Information: Over time the study of plants has revolutionized technology, allowing scientists to engineer solar panels, create cures and medicines, and even bring high definition television to the homes of millions. The examination of plants is interesting and useful, indeed, and this usefulness is definitely a factor in why the Photosynthesis Lab experiment was preformed.

Purpose of Study: The purpose of this study was to examine photosynthesis in plants and determine what variations of light is the most effective and most energy providing for the plants. In this experiment leaves were hole-punched and vacuumed then in water under a light with different colored filters to track its rate of photosynthesis.

Hypothesis: It was

hypothesized that once vacuumed the leaf discs would photosynthesis (oxidation rate) the most when it was under the white light filter and be the least effective when placed under the green filter. This is due to the fact that chlorophyll absorbs all rays of light except for green, the color which it reflects. The independent variable in this experiment is the time in minutes it takes for each leaf discs to oxidize, and the dependent variable is the oxidation rate to track photosynthesis.

Materials and Methods
Experiment 1
The supplies necessary for this experiment are the dyes (Toluidine Blue, Fast Green, Safranin, and leaf extract), a Vernier spectrophotometer, and a computer.
To do this experiment, first turn on the computer and connect it to the Vernier spectrophotometer. Next insert the different colors of dye into the Vernier spectrophotometer and record the results.
Experiment 2
To begin the photosynthesis lab it was crucial to obtain a couple supplies. The supplies needed were, 50ml beaker, one hole-puncher, a dropper, some dish liquid, fresh leaves, 8.5in x 11in translucent filters in green, blue, and red, 50ml syringe, one liter beaker, a timer, and lastly one lamp.
To begin this experiment, use the hole-puncher to punch 25 holes in the leaves. It is best to avoid any of the on the leaf. Once done remove the plug from the syringe and place the leave disks in side of it. Next place the plug back into the syringe. After that place the syringe on a flat surface and pick up the 50ml beaker. Go over to the sink and fill it up to the 50ml line with distilled water. Then add a drop of dish liquid in the beaker along with the water.
Do not stir. Once done, place the beaker down on a flat surface next to the syringe. Pick up the syringe. Then place the tip of the syringe into the water. Then slowly draw the plug back until the syringe is filled with 10ml of water. Do not shake it. Slowly flip the syringe until it is facing upright in a vertical line. The plug should be on the side closest to the ground. If there are bubbles in the syringe delicately push the plug inward until all bubbles are removed. Once bubbles are removed, firmly place one thumb on the tip of the syringe.
Now without removing the thumb from the tip, pull back the plug to the 20ml line. There will be a slight resistance. This is necessary in order to create a vacuum. Hold the plug there for 15 seconds then let go. Of the plug but do not let go of the tip. If done successfully then each leave disk will sink to the bottom. If the leave disks are still afloat repeat the vacuum process until they have all sunk. Once they have all sunk to the bottom push out any bubbles. Next gently place the syringe on a flat surface. Pick up the one liter beaker and walk over to the sink. Fill the beaker half way with distilled water. Next return to the syringe with beaker in hand, and place the beaker down on a flat surface.
Next, pick up the syringe and submerge it under the water in the beaker.

Remove the plug and dump out the leaf disks while still keeping the syringe under water. Avoid letting the disk contact the air because this could undo the effects of the vacuum. Once the leaf disks are out of the syringe and into the beaker remove the syringe and discard it. Next retrieve the lamp. Place the lamp on a flat surface with in the distance of an electrical outlet. Plug the lamp into the electrical outlet, but make sure the cord is safely out of the way. Place the beaker under the lamp and place one of the three filters over the beaker. Make a chart and record the number of disks that float over an hour’s time. Record the time in an interval of ten minutes. Once the experiment has been completed repeat the whole experiment with each of the other conditions of

light.
Experiment 3
The materials needed are Chromatography paper, a quarter, a leaf, leaf extract, filter paper, a test tube, and acetone and petroleum ether.
To perform this experiment, begin by using the dropper to place 5 drops of acetone and petroleum ether into the test tube. Then use the test tube lid to close the test tube. Next place a strip of chromatography paper on a flat surface. Once this is completed place one of the leaves on the paper about one centimeter away from the bottom. Once the leave is placed down on the paper, then pick up the quarter. Role the quarter back and forth on the leaf and press down firmly. Avoid tearing the chromatography paper. This action will get the leaf’s pigments out on the paper. Once the pigment can be seen on the paper place to quarter down and then open the test tube. Quickly, place the chromatography paper in the test tube vertically and then close the test tube. What 10 to 15 minutes and then record the distance the ether traveled on the chromatography paper.

Results
Experiment 1
When experiment 1 had been completed these were the following results. The blue solution absorbed the colors orange and surprisingly some blue. It also transmitted the colors blue and red. Next was the color green, and green absorbed both blue and green. While on the other hand it transmitted red. Then after green there was red, which absorbed the colors from spectrums purple through red. And surprisingly it did not transmit any colors and appeared to be black. Next was the Leaf extract. The leaf extract absorbed the colors from spectrum blue to purple, but when viewed to see which colors were transmitted it seemed to transmit all of them. The figure below shows the data table collected after the experiment.
Absorption and Transmitted
Solution Colors Absorbed Colors Transmitted
Blue Orange and some Blue Blue and Red
Green Blue and Green Red
Red Purple - Red None
Leaf Extract Blue - Purple All

Experiment 2
All in all, the experiment varied in results tremendously. The charts below show the graphs of the classes’ experiments in various light spectrum conditions. The title of each chart determines which light spectrum is being graphed. To determine how effective the spectrum of light was on photosynthesis the oxidation rate (y-axis) is recorded in the number of disks preformed oxidation over the course of sixty minutes (x-axis). The key shows what color corresponds to each lab section’s results and also what lab group number took the results. Based on the results the spectrum of light photosynthesis most effective in was red, blue, green, and then least effective in white.
Experiment 3
The figure below shows the pigment identity, color of the pigment, the distance the pigment traveled, and the Rf value. According to the data Chlorophyll b is green and traveled the least amount of distance (19mm). After that the second shortest distance is Chlorophyll a, which is yellow green in color, traveling 32 mm. Then next is Xanthophyll with 66mm, and a color of yellow. Finally, Carotene which is yellow-orange in color traveled a whole 100mm. It seems to appear that the color of the pigments slowly transitioned into one to the next. For instance in order it when from green to yellow-green, then yellow, to yellow-orange.
Chromatography Paper and leave Extract
Pigment Identity Color Distance Run (mm) Rf
Chlorophyll b Green 19 19/100
Chlorophyll a Yellow-green 32 32/100
Xanthophyll Yellow 66 66/100
Carotene Yellow-orange 100 100/100

Discussion
Experiment One
Looking back at experiment, I was surprised by the results my group had collected. It seemed somewhat shocking to me to find out that certain spectrums absorbed colors in their own spectrum as well. For instance in the chart “Absorption and Transmitted” the dyes fast green, Toluidine blue and Safranin all absorbed colors in their wavelengths, (Absorption and Transmitted). This might be because there are multiple wavelengths in the certain spectrum of light as are there are multiple shades and hues of pigments. I believe that this causes colors that may be classified as a shade of blue to be absorb because the shade of blue being reflected is of a different wavelength.
Experiment Two
The results ultimately did not support the hypothesis that once vacuumed the leaf discs would photosynthesis (oxidize) the most when it was under the white light filter and be the least effective when placed under the green filter.

In fact, the disks that were under the green filter ended up thriving. This may have been because the filter was not absorbing all light except green. When the filter paper was placed over my hand I could still see various hues of different colors through the paper easily. Although I had not even fathomed that this would cause complications in the experiment at the time, now that I have seen the results of green, where most of the disks were able to achieve photosynthesis, I know that other spectrums of light were the cause of this. Normally chlorophyll should not have been able to photosynthesize because chlorophyll reflects that spectrum of light, thus causing it itself to have a green color. One thing I did notice however was that my results that were conducted as an individual were closest to my hypothesis however it was still disproven. In the “Effectiveness of Photosynthesis in Different Spectrums of Light” chart for “Photosynthesis in Green Light” my results (Sec.2 Group 2) for the majority of the time the disks did not photosynthesize, but when they did only a total of three out of 2 out of 25 disks were able to. Although my prediction said that they would not be able to at all, I couldn’t help but notice that my results relatively were in

favor of my hypothesis.
Furthermore, it was also predicted that disks in white light would have been more successful. However the results show quite the contraire. Leaf disks under this spectrum oxidized the least. Some reasons for this could have been because the leaf disks in white light did not have a clear transparent filter over them. This may have caused the chlorophyll to have over heated and lose its effectiveness. This lack of consistence caused the white light to have different conditions that the other spectrum of light, and due to this design flaw, it caused the classes’ results to become askew.