Analysis
In an effort to observe the affects different types of light have on the growth of plants an experiment was conducted with four plants exposed to a variety of light sources such as sunlight, red light, blue light and green light. Plant 1 was the control and was exposed to natural light, plant 2 under red light, plant 3 under blue light and plant 4 under green light. Each plant received equal amounts of water and the growth rates and appearance of the plants was observed over the time period of 2 weeks. This process was repeated a total of three times in order to verify results.
A prediction was made that the control plant and the plants exposed to the blue and red lights will grow the best and that the plant exposed to the green light will not grow that well. It was also predicted that the control plant will grow the most, closely followed by the blue plant, which is followed by the red plant, which is followed by the green plant that will grow the least. This prediction was made as earlier research indicated that the colours absorbed and most utilized by a plant was limited to three distinct colours which include red, blue and yellow. Earlier research also indicated that green light will hinder plant growth as plants naturally reflect green wavelengths of light and therefore through the duration of the experiment the plant would absorb absolutely no light.
Although all research done prior to the start of the experiment indicated that the control plant would grow the best then closely followed by the blue plant and then the red plant, and also that the green light would hinder the growth of the plant and that it would grow the least, the pattern of the results was rather irregular and did not agree with the hypothesis and did not show the desired outcomes. The vertical height graphs demonstrating this below show a clear deviation from expected results in the growth of the plants under the green and red lights. There are several explanations possible for this event, but due to the sizes of the irregularities in this trial it is likely that a good portion of results were simply errors.
A prediction was made that the control plant and the plants exposed to the blue and red lights will grow the best and that the plant exposed to the green light will not grow that well. It was also predicted that the control plant will grow the most, closely followed by the blue plant, which is followed by the red plant, which is followed by the green plant that will grow the least. This prediction was made as earlier research indicated that the colours absorbed and most utilized by a plant was limited to three distinct colours which include red, blue and yellow. Earlier research also indicated that green light will hinder plant growth as plants naturally reflect green wavelengths of light and therefore through the duration of the experiment the plant would absorb absolutely no light.
Although all research done prior to the start of the experiment indicated that the control plant would grow the best then closely followed by the blue plant and then the red plant, and also that the green light would hinder the growth of the plant and that it would grow the least, the pattern of the results was rather irregular and did not agree with the hypothesis and did not show the desired outcomes. The vertical height graphs demonstrating this below show a clear deviation from expected results in the growth of the plants under the green and red lights. There are several explanations possible for this event, but due to the sizes of the irregularities in this trial it is likely that a good portion of results were simply errors.
The bar graph above displays the final height results of each of the plants that were exposed to the various lights in all three trials. Although it opposes the hypothesis the plants exposed to the red light has grown the least in all three trials. In one case the plant exposed to the red light does not even grow which is highly irregular as all four plants for each trial were taken care equally. A factor that may have caused or been involved in affecting this result could be the light intensity. Light intensity refers to the amount of light actually reaching to the surface of the plant as the more sunlight a plant receives, to a degree, the higher the photosynthetic rate will be. The thickness of the cellophane in the first trial could have been a factor that may have caused or been involved in the final outcome of the results as it would have restricted the amount of sunlight that reached the surface of the plant which then would then cause the plant to be unable to photosynthesis and grow, which then may have caused the plant to never grow. To prevent this result from reoccurring in the next few trials the decision was made to decrease the thickness of the cellophane.
Due to the knowledge obtained from earlier research the assumption was that the green light will be almost entirely useless for photosynthesis because most of the photosynthetic pigments in the plant are green (all chlorophylls) and would reflect green light meaning the plant would be absorbing no light at all and would be unable to grow, reproduce or photosynthesise. The results obtained from all three trials show that the plants exposed to the green light grew consistently well throughout the experiment although this greatly opposes the hypothesis. It is hard to understand how in the results, green was one of the the greatest plant in height, but also experienced the most lack of light. A factor that may have caused or been involved in affecting the final outcome of the results may have been the cellophane tents. This is because the cellophane does not supply the correct amount of light and the cellophane affects the opaqueness of the light meaning that when the light passes through the cellophane it scatters the light because of its rough surface.The best way to overcome this problem is to use coloured light bulbs.
Due to the knowledge obtained from earlier research the assumption was that the green light will be almost entirely useless for photosynthesis because most of the photosynthetic pigments in the plant are green (all chlorophylls) and would reflect green light meaning the plant would be absorbing no light at all and would be unable to grow, reproduce or photosynthesise. The results obtained from all three trials show that the plants exposed to the green light grew consistently well throughout the experiment although this greatly opposes the hypothesis. It is hard to understand how in the results, green was one of the the greatest plant in height, but also experienced the most lack of light. A factor that may have caused or been involved in affecting the final outcome of the results may have been the cellophane tents. This is because the cellophane does not supply the correct amount of light and the cellophane affects the opaqueness of the light meaning that when the light passes through the cellophane it scatters the light because of its rough surface.The best way to overcome this problem is to use coloured light bulbs.
The bar graph shown above displays the statistics of the average heights of the plants of each colour. This average was calculated using the results from all three trials of the experiment. The results presented show the plants that have been exposed to the blue light have the highest average of height (12.5), closely followed by the plants exposed to the sunlight or full colour spectrum (12.2), followed by the plants exposed to green light (11.5), and coming after are the plants exposed to the red light.
The vertical height graph shown above from trial 1 shows that the control plant which is exposed to direct sunlight or the full colour spectrum has a steady and consistent growth rate and ends up being the tallest of all the plants. This outcome was predicted in the hypothesis because the plant is able to absorb and utilise the colours blue, red and yellow which are the most important to enable the plant to grow, reproduce and photosynthesise. The plant exposed to the blue light has confirmed the hypothesis as the blue plant was predicted to be slightly behind the control plant. The plant has grown the second most because it is one of the major colours and wavelengths plants absorb. The blue light encourages vegetative growth through strong root growth and intense photosynthesis and often assists in flowering and the growth for seedlings and young plants. The green plant in the graph displayed above is equalling and at times taller than the plant exposed to the blue light. This is highly irregular as from earlier research the plant exposed to the green light should be unable to grow, reproduce, or photosynthesise as it is unable to absorb the green light. As mentioned before a factor that may have caused or been involved in affecting the results for the plant exposed to the red light could be the light intensity. Light intensity refers to the amount of light actually reaching to the surface of the plant as the more sunlight a plant receives, the higher the photosynthetic rate will be. The thickness of the cellophane in the first trial could have been a factor that may have caused or been involved in the final outcome of the results as it would have restricted the amount of sunlight that reached the surface of the plant which then would then cause the plant to be unable to photosynthesis and grow, which then may have caused the plant to never grow. To prevent this result from reoccurring in the next few trials the decision was made to decrease the thickness of the cellophane.
The vertical height graph shown above from trial 2 shows that the control plant and the plants that were exposed to the green and blue lights have very similar final results. Although the final height results were similar the growth patterns were quite different. The blue plant is the tallest of the four at most times but the growth pattern alters every now and then. The blue plant has a sudden cease in growth at around the 11 day mark and becomes equal with the red plant and becomes the shortest of all the plants. The blue plant then suddenly grows to become the tallest of the four in the time period of 3 days. The blue plant to some extent agrees with the hypothesis as it was predicted that the control plant would be closely followed by the blue plant, but in this case the blue plant is 0.5cm taller than the control. The control plant and the plant exposed to the green light follow very similar growth patterns except in the end where the control turns out to be 0.5cm taller than the green plant. The plant exposed to the red light sprouts and maintains around the same growth rate as the other plants until around day 7 where a gradual slow down in growth rate begins.
The growth rate of the plant was unusual and opposed the hypothesis as it was predicted that the plant exposed to the red light would be absorbed the best and would grow to be the third tallest. The red plant was meant to grow well because red light is the most important for photosynthesis, flowering and fruiting regulation. The wavelengths of the colour red encourage stem growth, flowering, fruit production and chlorophyll production. A factor that may have caused or been involved in affecting the results for the plant may be the humidity and temperature the plants were grown in. Because the plant was covered in a cone shaped piece of red cellophane, the dark red colour attracted heat and caused the area underneath the cellophane covering to become humid. This can be physically seen as when the covering was taken of, water droplets were seen formed along the side of the cone shaped covering. High humidity levels cause problems for plants because water vapour would begin to build on the surfaces of the plant when they actually need to lose the water vapour forming during photosynthesis and transpiration (a essential plant processes). High humidity levels also cause the development of a huge range of fungal and bacterial pathogens. These pathogens can destroy plants and even gardens. The most efficient way to solve this problem is to create holes in the cellophane covering so that the air can be circulated.
The growth rate of the plant was unusual and opposed the hypothesis as it was predicted that the plant exposed to the red light would be absorbed the best and would grow to be the third tallest. The red plant was meant to grow well because red light is the most important for photosynthesis, flowering and fruiting regulation. The wavelengths of the colour red encourage stem growth, flowering, fruit production and chlorophyll production. A factor that may have caused or been involved in affecting the results for the plant may be the humidity and temperature the plants were grown in. Because the plant was covered in a cone shaped piece of red cellophane, the dark red colour attracted heat and caused the area underneath the cellophane covering to become humid. This can be physically seen as when the covering was taken of, water droplets were seen formed along the side of the cone shaped covering. High humidity levels cause problems for plants because water vapour would begin to build on the surfaces of the plant when they actually need to lose the water vapour forming during photosynthesis and transpiration (a essential plant processes). High humidity levels also cause the development of a huge range of fungal and bacterial pathogens. These pathogens can destroy plants and even gardens. The most efficient way to solve this problem is to create holes in the cellophane covering so that the air can be circulated.
The vertical height graph shown above from trial 3 is very similar to the graph for trial 2 which verifies the results. The plant exposed to the blue light grew the tallest (12.5cm), followed by the control plant (11.5cm), followed by the green plant (10.5cm), followed by the red plant which grew the least (8cm). For all the plants the growth rates were steady and consistent and for the control plant, the green plant and blue plant the growth rate paths were similar. The red plant maintained the same growth rate after it had sprouted until around day 7 where it once again slowed down its rate. The control plant once again maintained the most consistent and steady in its growth whilst the blue plant was constantly changing it speed of growth as it was the tallest plant until day 8 but then there was a slow down in growth rate until just before day 11 it began to pick up pace.
In the image above the plant exposed to the red light from trial 1 is being held. The plant was dug out after the first trial had finished to check if the seed had germinated because in the results, graphs and pictures there was no visual sign of the plant. The picture above shows a small plant that has finished the germination process but looks yellow, weak and contains no roots. The most likely cause for this is insects as they have a direct impact on plants by chewing on leaves, sucking out plant juices, eating the roots stems or leaves of plants and spreading plant pathogens. Insects feed on natural fibres and speed up the process of decay. An insect probably used the cellophane covering as shelter and fed on the bean plants roots. The best way to keep out unwanted insects and pests from the plants is to use organic pesticides as it keeps out the insects and also is natural and doesn't harm your health.
Another difficulty that occurred during the experiment was that overnight at times the cellophane coverings for the plants would come of due to the wind. This meant that the experiments weren't 100% accurate as the plants at times received direct sunlight in the morning. The best way to respond to this problem is to either bring the plants inside or keep the plants in an area where the wind would have no affect. Another difficulty that occurred was that when it rained at times the controlled plant that was exposed to the direct sunlight received more water than the other plants as the other plants were covered in cone shaped cellophane covering meaning rain had no affect on them. This also meant that the rain and wind would have a harsher affect on the control plant compared to the other plants.
Another difficulty that occurred during the experiment was that overnight at times the cellophane coverings for the plants would come of due to the wind. This meant that the experiments weren't 100% accurate as the plants at times received direct sunlight in the morning. The best way to respond to this problem is to either bring the plants inside or keep the plants in an area where the wind would have no affect. Another difficulty that occurred was that when it rained at times the controlled plant that was exposed to the direct sunlight received more water than the other plants as the other plants were covered in cone shaped cellophane covering meaning rain had no affect on them. This also meant that the rain and wind would have a harsher affect on the control plant compared to the other plants.
In the images above, the number of leaves that were visible for each plant through the duration of the experiment has been recorded. These graphs are important as the main job of leaves is to make food for plants. This food making process is know as photosynthesis and occurs mostly in fully grown leaves. Leaves are essential for the well-being of a plant. It is the leaves that take in the light so if the plant does not have many leaves the process of photosynthesis is restricted and the growth of the plant slows down and the health of the plant is affected in a negative way.
Conclusion
In an effort to observe the affects different types of light have on the growth of plants an experiment was conducted with four plants exposed to a variety of light sources such as sunlight, red light, blue light and green light. Plant 1 was the control and was exposed to natural light, plant 2 under red light, plant 3 under blue light and plant 4 under green light. Each plant received equal amounts of water and the growth rates and appearance of the plants was observed over the time period of 2 weeks. This process was repeated a total of three times in order to verify results. A prediction was made that the control plant and the plants exposed to the blue and red lights will grow the best and that the plant exposed to the green light will not grow that well. It was also predicted that the control plant will grow the most, closely followed by the blue plant, followed by the red plant, which is followed by the green plant that will grow the least. This prediction was made as earlier research indicated that the colours absorbed and most utilized by a plant was limited to three distinct colours which include red, blue and yellow. Earlier research also indicated that green light will hinder plant growth as plants naturally reflect green wavelengths of light and therefore through the duration of the experiment the plant would absorb absolutely no light.
Looking back on the results obtained from the trials one, two and three of this experiment, and the different explored possibilities of how the different colours of light used in the experiment affected the growth of the plants in the discussion, it is possible to draw several conclusions and make final statements as to how these factors corresponded with the hypothesis. The results, to some extent, supported the hypothesis as the control plant grew the most steadily and consistently and the plants exposed to the blue light was either slightly taller or shorter than the control plant. But results such as the plants exposed to the green light growing as much as the control and the plants exposed to the blue light was irregular and unusual. Also the results from the plants exposed to the red light were also both unusual and irregular as plants absorb the colour red and its wavelength for the uses of photosynthesis. Factors such as light intensity, humidity, temperature, restricted light and insects had major impacts on the final results.
Looking back on the results obtained from the trials one, two and three of this experiment, and the different explored possibilities of how the different colours of light used in the experiment affected the growth of the plants in the discussion, it is possible to draw several conclusions and make final statements as to how these factors corresponded with the hypothesis. The results, to some extent, supported the hypothesis as the control plant grew the most steadily and consistently and the plants exposed to the blue light was either slightly taller or shorter than the control plant. But results such as the plants exposed to the green light growing as much as the control and the plants exposed to the blue light was irregular and unusual. Also the results from the plants exposed to the red light were also both unusual and irregular as plants absorb the colour red and its wavelength for the uses of photosynthesis. Factors such as light intensity, humidity, temperature, restricted light and insects had major impacts on the final results.