Elodea Leaves And Phenol Red Lab Report

In this experiment, we tested our hypothesis through the use of Elodea leaves and phenol red. Phenol red is an indicator that shows whether carbon dioxide is being consumed or produced. We also used 4 test tubes, phenol red, straw, pipette, aluminum foil, light, and a timer. We began this experiment by filling four beakers with phenol red. We labeled the tubes 1, 2, 3, and 4. We used a straw and blew into tubes 1 and 2 until it turned yellow, which indicates a lower pH and a higher carbon dioxide level. We placed the Elodea twigs into tubes 1 and 2. We then covered the top of all the tubes with aluminum foil. We placed tubes 1 and 3 in bright light and tubes 2 and 4 in the dark for 40 minutes. After 40 minutes, we took removed the tubes

Test tube 1 consisted of an Elodea leaf placed in phenol red. A group member blew into the tube to add more carbon dioxide to the phenol red, which changed the color from red to yellow. On a scale of 1 to 10, with 1 equaling to definite yellow and 10 equaling definite red, we rated the initial color of the test tube a 2. The test tube was then placed in the light for 40 minutes. After the 40 minutes, the test tube color had converted back to red (rating =10). This change in color occurred because the Elodea plant was preforming photosynthesis. The plant was using the carbon dioxide in the phenol red solution to carry out

Tube 4 consisted of a test tube with phenol red placed in the dark for 40 minutes. On a scale of 1 to 10, 1 equaling definite yellow and 10 equaling definite red, we rated the test tube as a 10. After 40 minutes in the dark, the test tube color changed from red to a red-orange, which we rated as 7. I did not expect this tube to change in color because it was the control. The Elodea leaf was not added to this test tube, so there was not anything placed in it to cause the change in color. The results of my experiment agree with my text. My text states that if carbon dioxide, oxygen and a light source is present, then the plant will carry out photosynthesis will begin. The plant will be unable to begin or carry out photosynthesis if the right components are not available (Farabee 2007). My hypothesis was partially correct. The tube containing the Elodea leaf placed under the light did change in color because photosynthesis was being performed. The tube containing the Elodea leaf placed in darkness did not change color because photosynthesis was not being performed. My hypothesis was partially incorrect because the control (tube 3 and tube 4) did not remain the same color. Tube 3 changed by 4 units from red to orange and tube 4 changed by 3 units from red to