LAB 3 Essay

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Words: 1511
Pages: 7

Measuring the production of oxygen in an aqueous environment of the specie Cabomba,
With temperature as a variable.

Janneke Zijsling
Lab 18- Section B
T.A: Sanjana


Photosynthesis is a sensitive process that responds in different ways depending on the environment and its changes. (Vargas and Cordero 2012). Recent studies have shown that there are many factors that affect the photosynthetic rate of plants. One study showed that the photosynthetic rate of tropical forest trees in the Northern Lowlands of Costa Rica is affected when the temperature increases. (Vargas and Cordero 2012). Using studies like the one mention above as a reference helped this experiment to formulate a hypothesis: The increase of temperature by 10C above room temperature (22C) will increase the photosynthetic rate, compare to the value at room temperature of the specie Camboba.

The materials used in the experiment three groups of materials. First the Manometric system which included three stoppers, 3 syringes, three pipettes, one tank and a source of light. Second, the materials that were used to make the Manometric system work: Three glass tubes, the plant material, which in this case was the specie cabomba, the conditioned or pond water, one plastic Pasteur pipette and the indicator (blue water). Finally additional materials like the test tube rack which was used to hold the glass tubes.
The way the experiment was performed included different steps: The first step in this experiment was to weigh out 3 to 4g of the plant that is going to be studied. Was important to zero the balance before weighing the plant. Two samples of the plants were needed, one for each experimental tube. After the plant was weighted, it was placed into the experimental tubes. Each tube was filled with pond water. The experiment needed to have a control sample to compare with the experimental tubes. The third tube was filled with pond water without adding the organism. The next step was to set up the Manometric system. Each tube stopped with a stopper. On one side of the stopper the syringe was introduced, and in the other side the pipette. Before plugging in the pipette, a small drop (3mm to 5mm) of blue water was added to the pipette using the plastic pipette. After the three tubes were ready, the droplet of blue water needed to be adjusted to the starting position. Using the syringe the droplet was adjusted to 0.5, which was the starting position. The tubs were ready at this point to be inserted in the tank. The next step was very important because the temperature of the water needed to be accurate to the treatment at which this experiment belonged. For this treatment was important to maintain the temperature of the water that is going to be placed inside the tank at room temperature, approximately 22 grades Celsius. The tank was filled with normal water at room temperature. When the tank was ready, the lamp, which is the light source, was placed in front of the tubes and at 15m away from the tank. We turned on the lamp and let the system stand for 15 minutes. This part of the experiment allowed the organisms to equilibrate to the variable. After some minutes the droplet moved slowly away from the direction of the stopper. This means that 02 was produced. After 15minutes, the droplet of blue water was adjusted to 0.5 again.
The system is timed by reading the position of the blue droplet in the pipette after 2 minutes. Data is collected after 2 minutes, in each tube. Timing and collecting data for 16 minutes was the next step. After this time the experiment will end. The last step was to clean all tubes and the tank and leave the workstation how it was before the experiment started.

In treatment #1, the production of oxygen after 2 minutes doesn't have a significant difference between the 6 groups that performed the experiment.