How Does The Wavelength Of Light Affect The Rate Of Photosynthesis
The effects of different wavelengths of light on the rate of photosynthesis
Introduction
This experiment was performed to investigate the effects of different wavelengths of light on the rate of photosynthesis. If a multiple colored film petri dishes are place under a 50 watt lamp, then the rate of photosynthesis will be greater for those with red, blue and clear film, than those with green and black film.
We believed the petri dishes with the red, blue and clear film would produce the best results of photosynthesis as compared to the petri dish with the green and black film. This is said because chlorophyll absorbs red and blue wavelengths of light and reflects green wavelengths of light. When referring to the light spectrum, red and violet are furthest away from green, and would be most absorbed by the leaf. White light is all the colors of the spectrum, and would have results similar to …show more content…
that of red and blue.
Below is a chart provided by Daniel Winik of Sidwell Friends School in Washington, DC.
A similar experiment was done using Arabidopsis thaliana plants. The purpose of his experiment was Òto observe the effects of different wavelengths of light on the rate of photosynthetic rate in Arabidopsis thaliana plants.Ó
By using petri dishes with colored film, and spinach disks, we are allowing only certain wavelengths to pass through and show the rate of photosynthesis. If the experiment is done properly, it will provide us with the expected results. As the wavelengths are allowed to pass through the spinach disks will begin to float or remain the sunken at the bottom of the petri dish. The spinach leaves will float once enough O2 (a product of photosynthesis) has been accumulated.
If the hypothesis is supported, the petri dishes with the red, blue and clear film will provide the best rate of photosynthesis. The independent variable would be the wavelength of light and the dependent variable is the rate of photosynthesis measured by a percentage.
Materials
The materials needed for this experiment will consist of petri dishes with a variety of films. The colors for this experiment will be red, blue, green, clear, and black film, to cover the petri dishes. The experiment will be performed using spinach disks, which are spinach leaves that have circles punched out using a cork borer. There will need to be 20 spinach disks for each petri dish, totaling 100 spinach disks. All of the spinach disks will be placed in a beaker containing a bicarbonate solution. The beaker will then be covered by a rubber stopper, and hooked up to a water aspirator. A water aspirator will be used as a vacuum source to sink the disks. You will also need to pour 0.2% NaHCO3 into each petri dish, so it is about 2/3 full. An estimated amount of NaHCO3 would be 100 Ml. The petri dishes will then be placed under a 50 watt lamp, 25 cm for the base, for a time period of 20 minutes.
Results
The results can are expressed in the Table 1 shown below:
Wavelength Number floating Percentage
White 20 100
Red 18 90
Blue 6 30
Green 0 0
Dark 0 0
After the petri dishes had sat under a lamp for 20 minutes, the petri dish with the clear film had the best results. This is followed by the petri dish with the red film, then the petri dish with the blue film. The petri dishes with the blue and black film had shown no photosynthesis took place. Graph 1, shown below, shows the results of the effect of different wavelengths on the rate of photosynthesis
Discussion
The hypothesis was proven true in the sense that the petri dish with the red, blue and clear film had the highest rate of photosynthesis, compared to the petri dish with the green and black film. I expected the blue filmed petri dish to have a higher rate of photosynthesis than 30 percent.
The petri dish with the clear film allowed white light to pass; white light includes all the colors of the spectrum, including green. Figuring that red and blue wavelengths are furthest away from green, and absorbed by the chlorophyll, I expected the highest rate of photosynthesis to be with the red and blue filmed petri dish.
Ideally, each dish would be placed under an individual lamp. This could have caused the blue and green filmed petri dish not to have as much light as the other petri dishes. Another problem could have been the film covering the petri dishes was too thick and left room for error. With the petri dishes being too thick, there is a possibility that a substantial amount of light was unable to pass through and effected the rate of photosynthesis. Another complication may have been using artificial light and not the natural light provided by the sun.
To improve the experiment, I would have each petri dish under the lamp for a period of 60 minutes versus 20 minutes. I would also have one petri dish to one lamp, instead of all petri dishes under the same lamp, and have more than one of each color filmed petri dish. I would also like to use more colors of the light spectrum by including yellow, violet, and orange.
In conclusion, the clear and red filmed petri dishes had the best results for photosynthesis. I feel the results could have been more accurate if each petri dish was placed under its own light and left for a period longer than 20 minutes. The experiment showed photosynthesis occurs best when under white light.
Sources:
ÒEssential Biology, second edition.Ó Campbell, Reece, Simon. Photosynthesis. Pages 102-116
Marinaccio, James. ÒPrinciples of Biology Laboratory Manual.Ó Pages 188-192.
Winik, Daniel. The Sidwell Friends School. ÒImpact of Light Wavelength on Photosynthetic Rate in Arabidopsis thaliana.Ó
Introduction
This experiment was performed to investigate the effects of different wavelengths of light on the rate of photosynthesis. If a multiple colored film petri dishes are place under a 50 watt lamp, then the rate of photosynthesis will be greater for those with red, blue and clear film, than those with green and black film.
We believed the petri dishes with the red, blue and clear film would produce the best results of photosynthesis as compared to the petri dish with the green and black film. This is said because chlorophyll absorbs red and blue wavelengths of light and reflects green wavelengths of light. When referring to the light spectrum, red and violet are furthest away from green, and would be most absorbed by the leaf. White light is all the colors of the spectrum, and would have results similar to …show more content…
that of red and blue.
Below is a chart provided by Daniel Winik of Sidwell Friends School in Washington, DC.
A similar experiment was done using Arabidopsis thaliana plants. The purpose of his experiment was Òto observe the effects of different wavelengths of light on the rate of photosynthetic rate in Arabidopsis thaliana plants.Ó
By using petri dishes with colored film, and spinach disks, we are allowing only certain wavelengths to pass through and show the rate of photosynthesis. If the experiment is done properly, it will provide us with the expected results. As the wavelengths are allowed to pass through the spinach disks will begin to float or remain the sunken at the bottom of the petri dish. The spinach leaves will float once enough O2 (a product of photosynthesis) has been accumulated.
If the hypothesis is supported, the petri dishes with the red, blue and clear film will provide the best rate of photosynthesis. The independent variable would be the wavelength of light and the dependent variable is the rate of photosynthesis measured by a percentage.
Materials
The materials needed for this experiment will consist of petri dishes with a variety of films. The colors for this experiment will be red, blue, green, clear, and black film, to cover the petri dishes. The experiment will be performed using spinach disks, which are spinach leaves that have circles punched out using a cork borer. There will need to be 20 spinach disks for each petri dish, totaling 100 spinach disks. All of the spinach disks will be placed in a beaker containing a bicarbonate solution. The beaker will then be covered by a rubber stopper, and hooked up to a water aspirator. A water aspirator will be used as a vacuum source to sink the disks. You will also need to pour 0.2% NaHCO3 into each petri dish, so it is about 2/3 full. An estimated amount of NaHCO3 would be 100 Ml. The petri dishes will then be placed under a 50 watt lamp, 25 cm for the base, for a time period of 20 minutes.
Results
The results can are expressed in the Table 1 shown below:
Wavelength Number floating Percentage
White 20 100
Red 18 90
Blue 6 30
Green 0 0
Dark 0 0
After the petri dishes had sat under a lamp for 20 minutes, the petri dish with the clear film had the best results. This is followed by the petri dish with the red film, then the petri dish with the blue film. The petri dishes with the blue and black film had shown no photosynthesis took place. Graph 1, shown below, shows the results of the effect of different wavelengths on the rate of photosynthesis
Discussion
The hypothesis was proven true in the sense that the petri dish with the red, blue and clear film had the highest rate of photosynthesis, compared to the petri dish with the green and black film. I expected the blue filmed petri dish to have a higher rate of photosynthesis than 30 percent.
The petri dish with the clear film allowed white light to pass; white light includes all the colors of the spectrum, including green. Figuring that red and blue wavelengths are furthest away from green, and absorbed by the chlorophyll, I expected the highest rate of photosynthesis to be with the red and blue filmed petri dish.
Ideally, each dish would be placed under an individual lamp. This could have caused the blue and green filmed petri dish not to have as much light as the other petri dishes. Another problem could have been the film covering the petri dishes was too thick and left room for error. With the petri dishes being too thick, there is a possibility that a substantial amount of light was unable to pass through and effected the rate of photosynthesis. Another complication may have been using artificial light and not the natural light provided by the sun.
To improve the experiment, I would have each petri dish under the lamp for a period of 60 minutes versus 20 minutes. I would also have one petri dish to one lamp, instead of all petri dishes under the same lamp, and have more than one of each color filmed petri dish. I would also like to use more colors of the light spectrum by including yellow, violet, and orange.
In conclusion, the clear and red filmed petri dishes had the best results for photosynthesis. I feel the results could have been more accurate if each petri dish was placed under its own light and left for a period longer than 20 minutes. The experiment showed photosynthesis occurs best when under white light.
Sources:
ÒEssential Biology, second edition.Ó Campbell, Reece, Simon. Photosynthesis. Pages 102-116
Marinaccio, James. ÒPrinciples of Biology Laboratory Manual.Ó Pages 188-192.
Winik, Daniel. The Sidwell Friends School. ÒImpact of Light Wavelength on Photosynthetic Rate in Arabidopsis thaliana.Ó