Plants To Green And Red Light example essay topic

Let There Be Light Introduction When we look at the sun, what do we see Other than to squint our eyes and put your sunglasses on, you can see that the light is very bright and white-yellow in color. However, looking at light through a prism relates a different story. If Light is put up against a prism it is refracted or bent into a rainbow which contains the primary colors of light in which red light bends the least and violet bends the most (Jude, 1999). The primary colors of light consist of red, orange, yellow, green, blue, and violet. Light is a wave that consists of oscillation in electric and magnetic fields that can travel through space. Plants absorb light in a process called photosynthesis (Gammon, 1999).

Photosynthesis is defined as the process by which green plants and certain other organisms use the energy of light to convert carbon dioxide and water into the simple sugar glucose. Photosynthesis provides the basic energy source for virtually all organisms. An important byproduct of photosynthesis is oxygen, on which most organisms depend. Plant photosynthesis occurs in leaves and green stems within specialized cell structures called chloroplasts. One plant leaf is composed of tens of thousands of cells, and each cell contains 40 to 50 chloroplasts.

The chloroplast, an oval-shaped structure, is divided by membranes into numerous disk-shaped compartments. These disk like compartments, called thylakoids, are arranged vertically in the chloroplast like a stack of plates or pancakes. A stack of thylakoids is called a gran um (plural, grana); the grana lie suspended in a fluid known as stroma. Embedded in the membranes of the thylakoids are hundreds of molecules of chlorophyll, a light-trapping pigment required for photosynthesis.

Additional light-trapping pigments, enzyme (organic substances that speed up chemical reactions), and other molecules needed for photosynthesis are also located within the thylakoid membranes. The pigments and enzymes are arranged in two types of units, Photosystem I and Photosystem II. Because a chloroplast may have dozens of thylakoids, and each thylakoid may contain thousands of photosystem, each chloroplast will contain millions of pigment molecules. (Jude, 1999). This light converting into energy occurs in all plants.

Photosynthesis is responsible for plant growth and development due to light energy from the sun. This experiment asked the question, Which type of light do plants favor the most A total of eighteen plants were subjected to two different types of light, nine were subjected to red light and nine were subjected to green light. In carrying out the experiment I devised a null hypothesis and an alternate hypothesis, Ho - There is no difference between growth rates in plants subjected to green light verses plant growth in plants subjected to red light. Ha - There is a difference between growth rates in plants subjected to green light verses plant growth in plants subjected to red light.

METHOD The procedure in conducting this experiment was very basic. The materials used in this experiment included; twenty pea seeds with radicle showing, 1 - 2 gallons of water, two planting trays with 3 X 4 planting containers, so a total of twelve of which only 10 were used, potting soil, a small shovel, red and green bulb lamps. Note: This experiment was carried out under no other exposure of light other that the ones being tested (red & green). To limit the amount of undesired light and prevent an overlap of light between the two colors, cardboard boxes were put around and in between the two plant trays. Attempt to find a room that is dark as possible with the least amount of visible light to setup this experiment, place potting soil in the 3 X 4 tray containers until half-full. Place pea seed in potting soil, pushing down slowly until the pea seed was half under the soil and a green radicle could be seen.

Place red and green lamp around the trays making sure there is no overlap of light. Surround the area with cardboard. Water each individual container. Note: Take all measurements in Centimeters. Record all measurements in notebook. Describe the plants and how they are growing, e.g. withered, fallen down, weak, etc.

Results My findings showed me that green light plants grow at a faster rate than red light plants do. This was confirmed by the provided graphs on the preceding pages. The statistical tests of the significance of the difference between two groups or the t-test is also shown in the preceding pages. I started recording data after leafs had shown. On first day of recording data, the green light plants seemed very alive With tiny leafs at the upper part of plant, the red light plants seemed withered and not much growth observed. The second day, one could determine that the green light was better for the plants.

The green light plants were very elongated with tiny leafs and some had fallen over. The red light plants were showing minimal growth but were strong and did not fall over. The last day the green light plants were all over the tray container. They were all like vines with little or no leafs. The red leafs were all standing upright and showed some growth, they had more branches on top and less on bottom.

There were inter-nodel difference recorded where the red light plants were 5 cm apart from node to node and the green light inter-nodel differences of 6-8 cm apart. These values were all on average. Discussion: Interpretation of the given graphs clearly shows that the green light plants grew higher in length compared to the red light plants. Interpretation of the t-test shows that there was a significant amount of difference in my groups. The t-test supports my results. The red and green light plants both grew more vertically than horizontally because they lacked the required light to grow leafs and branch more horizontally.

This points out that plants do not use only one type of light for energy. An interesting observation that was noted was that the green light plants were all fallen over but the red light plants were standing upright. This leads us to speculate that red light plants grow at a slower rate then green light plants but red light plants are more stronger. The results accepted the alternate hypothesis (Ha). Research on how light behaves and is absorbed provided some insight as to what is actually going on in this experiment. A substance absorbs a single type of light and reflects back the light not absorbed.

For example, the green plants in this experiment can be described as being green in color, meaning that the plants are absorbing all the other colors of light on the visible spectrum and reflecting back green which is what your eyes see (Gammon, 1999). This is related to my experiment because green plants need many different colors of light from visible spectrum, this experiment only subjected plants to green and red light resulting in more vertical growth due to the deficiency of required colors of light. Experimental error in this experiment could have occurred due to undesired light coming in from uncovered portions of the experimental area. Error possibly occurred due to times data was recorded, three days spanned over two weeks including weekends so there was no daily recording of data, that is why there is good amount of increase on the last day. The time frame of this experiment was three days. An experiment done with a longer time frame could have shed better light on the subject.

No pun intended. Gammon, Steven D. 1999 General Chemistry, Houghton Mifflin Co. Boston, MA Jude, Alex 1993-1999 Encarta 99, Microsoft Corp., CD.