Temperature Effect on Photosynthesis Chandler, Kyle, Elsa

Research Question: Does temperature affect the rate of photosynthesis?

Hypothesis: If an experiment was conducted to test the rate of photosynthesis in room, cold, and warm temperature environments, then the leaves in the warm temperature environment will photosynthesize completely the fastest. In order for photosynthesis to occur, a plant needs a source of light and the most common one is the sun. Since the sun gives off radiant heat, the set up in the warmer temperature setup is similar to the sun, since there is both heat and light, and therefore the leaves will photosynthesize the fastest.

Since this experiment was conducted to determine if temperature affects the rate of photosynthesis, the control group used in this experiment was the room temperature environment. Since the experiment had already been conducted in a room temperature environment, it was a control that could be used to compare with the results of the cold and warm temperature environment. Additionally, the leaves in the room temperature environment successfully photosynthesized at a steady rate, so the rates can be compared as faster, slower, or not at all. Control Group:

● The lamp was 5 cm away from each beaker. ● The lamp had a CFL light bulb that does not give off any heat, only light. ● The disks all came from spinach leaves. ● The bicarbonate soap solutions were made with the same amount of water (100 mL), baking soda (0.08 g), and dish soap (1 drop). ● All of the syringes used to infiltrate the leaves were brand new. Controls:

Procedure: Bicarbonate Solution 1.Create the bicarbonate soap solution by filling mL beakers with 100 mL of water. Next, add 0.08 g of baking soda and one drop of dish soap to each beaker. Mix the solution slowly and gently so that no bubbles are formed by the soap, but that all the ingredients are mixed.

2.While making the bicarbonate soap solution, have another group member set up the design for each part of the experiment; the room temperature trials, the cold temperature trials, and the room temperature trials. The room temperature set up consisted of a lamp with a CFL light bulb. The cold temperature set up consists of a styrofoam box that is half filled with ice with another CFL light bulb. The warm temperature set up consists of 2 1,000 mL beaker that are each filled with 800 mL of water and then placed on a hot plate. Once the bicarbonate soap solutions were made, two beakers of the solution were placed in each setup 10 cm away from the lamp. The room temperature beakers were placed on the lab counter, the warm beakers were placed in each 1,000 mL beaker of hot water on the hot plate, and the cold temperature beakers were placed in the styrofoam box of ice. Then, a thermometer was placed in each of the bicarbonate soap solution beakers. Procedure: Set up

Procedure: Setup Pictures Thermometer Lamp with CFL light bulb Sodium Bicarbonate Soap Solution (100 mL) and 12 Leaf Disks 150 mL beakers Styrofoam box filled with ice

Procedure: Setup Pictures 150 mL beaker with 100 mL Bicarbonate Soap Solution and 12 leaf disks Lamp with CFL light bulb Thermometer Hot Plate 1,000 mL beaker of water

Procedure: Setup Pictures Lamp with CFL light bulb 150 mL beaker with 100 mL Bicarbonate Soap Solution and 12 leaf disks Thermometer

Procedure: Leaf Infiltration 3.After creating the bicarbonate soap solutions and setting up, have another group member hole punch spinach leaves until there are 72 total leaf disks. Then, separate the leaves into 6 plastic syringes so that there are 12 leaves in each syringe. Additionally, in each syringe, add the bicarbonate soap solution from the corresponding beaker (one syringe per beaker) until the syringe is about ⅓ full. Infiltrate the leaves in the syringe and place them in a dark space until it is time for the experiment.

4. Once the room temperature beakers are around 20 degrees Celsius, the warm beakers are around 55 degrees Celsius, and the cold beakers are around 5 degrees Celsius, the infiltrated leaves in each syringe are put into each beaker so that each beaker has 12 leaves that sink to the bottom. Immediately, the temperature for each beaker is recorded and the initial amount of leaves floating is recorded in the data table under 0 minutes, and the stopwatch is started. For 25 minutes, the number of leaves floating in each beaker is recorded every minute. Procedure: Running the Experiment

Data Table:

Graph: Individual Data Caption: This graph shows the number of leaves floating in each beaker of each trial every minute for 25 minutes. In the graph, there are three clear groups of data. These groups are the warm, room, and cold temperature trials. The warm temperature trials had all leaves floating the fastest, then the room temperature leaves at around 15 minutes. None of the leaves in the cold temperature trials floated.

Graph: Averaged Data Caption: This graph is of the average number of leaves floating every minute for the room, cold, and warm temperature trials. Since each temperature had four trials, the average number of leaves for each minute was calculated. This more clearly shows the results of the experiment because it is clear that the leaves in the warmer trials floated faster than the room temperature trials, and that the cold trials did not have any leaves float.

Even though the purpose of the experiment was to determine whether temperature affects the rate of photosynthesis, the data collected was the number of leaves floating in the bicarbonate solution over minutes. First, the bicarbonate soap solution was special because it setup the leaves. The baking soda (0.08 g) was mixed into the water to act as a source of carbon which is needed in photosynthesis to make glucose. Also, the drop of dish soap was used to remove the waxy cuticle on the leaf so that oxygen could flow in and out. Second, the leaves were infiltrated so that there was no oxygen in the leaf; therefore, the leaves sank in the beaker. However, when a source of light was applied to the beaker, the leaves began to photosynthesize since they had all the components needed. Once photosynthesis occurred, the leaves would float because oxygen is being created, making them less dense than the solution. Ultimately, the rate of photosynthesis in this experiment is measured through the number of leaves floating every minute. The sooner all the leaves float, the faster the rate of photosynthesis was. With this said, the data can be analysed and further examined to answer the question. Analysis: Purpose of Procedure

Analysis: Room Temperature Throughout the experiment, the data and graphs showed that the leaves in the room temperature environment took longer than the cold temperature leaves to float, but longer than the warm temperature leaves to float. This indicates that the leaves photosynthesized at a steady rate that was faster than leaves in a cold environment but slower than leaves in a warm environment. Most of the data was consistently similar in the room temperature trials except for trial 2. In trial 2, the leaves did not start floating until 18 minutes had passed. Since the solutions and the leaves were the same and the light was placed the same distance away, it was concluded that the beaker for that particular trial was most likely contaminated which compromised the data. Despite the one contaminated trial, the data was consistent. In comparison to the warm temperature, the room temperature leaves had a much slower rate of photosynthesis.

Analysis: Cold Temperature In every cold temperature trial, none of the leaves floated. This shows that photosynthesis did not occur in an environment that was about 5 degrees Celsius. This lack of photosynthesis could have occurred for many different reasons. First, the spinach plant is known as a herbacious plant because it does not have a woody tissue to last through the winter; therefore, photosynthesis stops. The temperature during the winter in most places easily falls to 5 degrees Celsius which is just above freezing. If spinach plants die in the winter because they freeze and break, then they cannot photosynthesize. In the experiment, the leaves were probably too cold to photosynthesize since they die in the winter.

In the experiment, the leaves in the warm temperature environment floated the soonest; therefore, they had the fastest rate of photosynthesis. Even though the results support the hypothesis, the reasoning in the hypothesis was incorrect. The leaves in the heat did not photosynthesize faster because of radiant heat since photosynthesis needs a source of light, not sunlight, and heat and light are completely different. On the other hand, the leaves in the warm temperature environment photosynthesized the fastest because enzymes that catalyze the chemical reactions in photosynthesis perform better at higher temperatures. Also, the warm trials had all leaves floating within the first five minutes of the experiment, which is extremely fast. The explanation for this rapid rate of photosynthesis is that the experiment environment was too friendly. Since everything needed for photosynthesis was available to small pieces of plants, it was easy to photosynthesize. In an actual plant outside, the air is dry, which slows down the productivity of photosynthesis. However, since the leaves were in water, they had plenty of water, thus increasing the productivity. Overall, spinach leaves photosynthesize the fastest in a warm temperature environment because the enzymes that catalyze chemical reactions in photosynthesis perform better and faster at warmer temperatures than colder temperatures. Analysis: Warm Temperature

● After infiltrating the leaves make sure the syringe with the leaves and solution are put in a dark place, if not photosynthesis will begin to occur if left in the light. This may have caused the leaves to have been slightly photosynthesized before beginning the experiment; therefore, the leaves may have floated sooner. ● When the thermometer is in the beaker make sure it’s not touching the glass but it’s suspended in the water to get a more accurate reading. If done, this could affect the temperature data. ● Since the leaves were small and everything that is needed in photosynthesis was provided in the setup, it may not have accounted for the realistic photosynthesis behavior of an entire plant. ● Also, plants outside are usually in an environment where the air is dry which would decrease the productivity of photosynthesis. In the experiment, the leaves were in a solution that contained water; therefore, the results of the experiment may be that photosynthesis occurred at a faster rate compared to real plants. Experimental Errors:

Conclusion: All in all, if an experiment was conducted where the rate of photosynthesis was tested in room, cold, and warm temperature environments, then the subject being tested in the warm temperature environment will float first. This is because in order for photosynthesis to occur, a plant needs a source of light. Since light can be compared to the sun and the sun gives off radiant heat, the set up in the warmer temperature group is most similar to the sun and therefore will photosynthesize the fastest. Therefore, the warmer temperature environment was thought to have the fastest rate of photosynthesis. This hypothesis was supported after completing the experiment because the data directly showed that the warmer temperature had the fastest rate of photosynthesis because all of the leaf disks were floating in almost a matter of seconds. However, since only light is necessary in photosynthesis, not heat from sunlight, it was concluded that the leaves in the warm temperature environment had the fastest rate of photosynthesis due to enzymes that catalyze chemical reactions in photosynthesis that work better at higher temperatures. All in all, the rate of photosynthesis is affected by the temperature at which the subject being photosynthesized is kept in.