Name(s): ______Block: ______Date: ______
Factors Affecting Photosynthesis: Waterweed Simulation
Introduction: In this simulation, you will be looking at the production of oxygen as a plant photosynthesizes. This procedure can be accomplished by placing elodea (waterweed) plants in water with baking soda to provide carbon. The plant can then be exposed to varying intensities and colors of light. The number of bubbles produced by the plant can then be measured. This simulator addresses three factors that influence the rate of photosynthesis. Carbon dioxide availability, light intensity, and light color can all be adjusted in the simulator to determine how each of the factors affects the rate of photosynthesis.
Site: http://www.saddleworth.oldham.sch.uk/science/simulations/waterweed.htm
1. What was the purpose of mixing baking soda the water? ______
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2. What are three factors that can affect the rate of photosynthesis in a plant? ______
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3. There is another factor that is not tested here which could affect the rate of photosynthesis in a terrestrial plant. What is it? ______
Experiment 1. Affect of Light Color on the Rate of Photosynthesis
Set the simulator to 6.0 Light Level, and 6.0 CO2 Level. Adjust the colors to complete the table. The simulator will run for 30 seconds.
Light Color / Number of BubblesLight = 6, CO2 = 6)
Red
Blue
Green
Colorless (White)
4. What is the independent variable in this experiment? ______
5. What is the dependent variable in this experiment? ______
6. Based on the data, what color of light results in the fastest rate of photosynthesis? Propose an explanation for these results. ______
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Experiment 2. Affect of Light Level on Photosynthesis
Set the simulator to colorless light and CO2 level to 6.0. Make adjustments to the level of light to complete the data table. The simulator will run for 30 seconds.
Light Intensity / Number of BubblesLight = Colorless, CO2 = 6)
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
7. What is the independent variable in this experiment? ______
8. What is the dependent variable in this experiment? ______
9. What are two factors that you controlled? ______
10. Based on the data, what light level results in the fastest rate of photosynthesis? Propose an explanation for these results. ______
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Experiment 3. Affect of CO2 Level on Photosynthesis
Develop an experiment to test how the level of CO2 affects the rate of photosynthesis. Construct a data table in the space below that shows the data you collected. Make sure to include information such as the color of light, light intensity, level of CO2 and the amount of
bubbles produced.
11. What is the independent variable in this experiment? ______
12. What is the dependent variable in this experiment? ______
13. Based on the data, what CO2 level results in the fastest rate of photosynthesis? Propose an explanation for these results. ______
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Create a graph of your data in the space below.
15. Write the equation for photosynthesis.
16. What are the bubbles produced by the plant? Explain why bubbles happen.
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17. Summarize HOW do different factors affect the rate of photosynthesis? Use evidence from your lab to support your answer. ______
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18. What would happen to a plant that was only exposed to green light? Why? ______
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19. Why is it important that you keep two variables constant (such as light level and color) while you're testing how a third variable (CO2 Level) affects photosynthesis?
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20. What settings would you put the simulator on to get the MAXIMUM rate of photosynthesis?
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Adapted from: http://www.biologycorner.com/worksheets/waterweed_sim.html 12/1/2011