The Effect of Temperature on the Rate of Photosynthesis ...

The Effect of Temperature on the Rate of Photosynthesis [First and last name]

POLYTECH High School

[Date]

Abstract This experiment was conducted in order to see if the temperature of an

environment has an effect on the rate at which the plants in that environment perform photosynthesis. Two trials were held, one with the leaves at room temperature and one with the leaves at a temperature of 35o C (95o F). The hypothesis tested was: If the plants are at a lower temperature, the rate of photosynthesis would be more rapid. Each trial was conducted for ten minutes each, and the data was recorded and graphed using a LabQuest. The room temperature trial maintained a rate of carbon dioxide consumption by the plant of -0.079724 ppm/s. The higher temperature had a rate of 0.044447 ppm/s. The hypothesis was supported because the plants had a faster rate of photosynthesis at the lower temperature.

Introduction The purpose of this experiment was to test whether or not raising the

temperature in an environment would effect the rate of photosynthesis. In the process of photosynthesis, a plant uses carbon dioxide, water, and light energy in order to produce oxygen and glucose. Once the temperature was raised, the group tracked the amount of carbon dioxide remaining over a period of time in order to gather the results. The independent variable in the experiment was the temperature of the chamber. The dependent variable was the carbon dioxide concentration over time. The constants in the experiment would be the number of leaves in the chamber, and the materials we used, such as the carbon dioxide sensor, LabQuest, hot plate, and the light source. The group's hypothesis was that at a lower temperature, the carbon dioxide concentration

would decrease more rapidly.

Materials and Methods In order to conduct this experiment, certain materials and methods were needed.

A plastic chamber was lined with enough plant leaves to cover the surface of the bottom. The carbon dioxide sensor was placed inside, and the lamp was placed above to shine directly onto the chamber. The LabQuest was attached to the sensor and set up to track and graph the concentration of carbon dioxide within the chamber. After allowing five minutes for equilibration, the data collection began. Once it was complete, the graph was saved to a USB drive and a second trial was prepared. The second trial called for the plastic chamber to be placed in a metal pan so that heated water could be poured in around it. The lid to the chamber was removed while waiting in order to let the accumulated carbon dioxide and oxygen escape. A beaker of 300mL of water was placed onto a hot plate and heated to a temperature of 35o C (95o F). A thermometer was placed in the beaker to determine when the water was hot enough. At this time, the lid was placed back onto the chamber, and the sensor was once again given time to equilibrate. Once the appropriate temperature was reached, the group poured the water into the metal pan surrounding the chamber and the data for the second trial was collected. Throughout this second trial, the temperature of the water dropped as time passed, so more hot water was added in order to keep up the correct temperature. When the ten minutes were over, this graph was also saved onto a USB drive, and the materials were cleaned up and put away.

Results

The Rate of Photosynthesis at Room Temperature

Figure 1: This graph shows the rate at which carbon dioxide concentration is decreasing in a 23o C environment.

The Rate of Photosynthesis in a Heated Environment

Figure 2: This graph shows the rate at which carbon dioxide concentration is decreasing in a 35o C environment

Rate without heat Rate with heat

-0.079724 ppm/s -0.044447 ppm/s

Table 1: This table shows the rate of carbon dioxide consumption by the plant, based on the data collected from the carbon dioxide sensor in the two trials.

Discussion The results of this experiment supported the group's hypothesis, because

photosynthesis occurred more quickly at the lower temperature. When the leaves were at a temperature of 23o C, the carbon dioxide diminished at a rate of -0.079724 ppm/s. When the temperature increased to 35o C, the carbon dioxide diminished at a rate of 0.044447 ppm/s. In the results from the experiment, it is shown that in a room temperature chamber, the decrease is more rapid, and there is not as much fluctuation as there is in the higher temperature environment. The hypothesis was supported by the results. The leaves performed photosynthesis at a faster rate when placed in a room temperature environment, compared to being in a much warmer environment. This is evidence that photosynthesis in this specific plant is more efficient at a cooler temperature, and when that temperature increases, even by only 12o C, there is a decrease in the rate of photosynthesis.

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