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Photosynthesis

Investigation 2 – PostLab

 

 

 

 

 

 

 

ANALYZE IT

Note: Questions marked with a triangle (∆) are included to enrich your understanding. These questions do not appear in your SDR but should be used as additional discussion points during the PostLab.

  •  As a class, discuss the carbon dioxide experiment.

Note: It is helpful if the equation used to represent photosynthesis can be displayed on the board for this discussion.

  • ∆ How does photosynthesis involve carbon dioxide? 
  • ∆ What do you suppose happened to the carbon dioxide in the test tube with the Elodea? 
  • ∆ If photosynthesis occurred in the test tube, decreasing the amount of carbon dioxide, what happened to the pH of the water? 
  • ∆ If the water became more basic, toward what color would the water have changed? 
  • ∆ Did your results match this conclusion? 
  • Discuss the data collected using the oxygen meter.

Note: It is helpful if the equation used to represent photosynthesis can be displayed on the board for this discussion.

 

 

  • ∆ Why did half of the class measure the oxygen content in water and the other half measure oxygen content in water with Elodea? 
  • ∆ How does Elodea affect the level of dissolved oxygen in water? 

 

Complete the Analysis Questions in your SDR then discuss them as a class. 

  • Did you see a change in the color of the water in the two test tubes? If so, what might the change in color represent? 
  • Graph: Use the grid below to make a graph that compares time to oxygen level in a beaker of water with or without Elodea. Draw a best fit line through your data points. If you need help, refer to the procedure, Drawing of a Best Fit Line.

  • Based on your graphed data, do you observe any trend in oxygen level over time? 
  • What may have caused the observed change in the level of dissolved oxygen? 

GET FOCUSED

Complete the Focus Questions in your SDR then discuss them as a class.

  • How do light and photosynthesis affect carbon dioxide levels?

  • How do light and photosynthesis affect oxygen levels?