# The Effects of Light Intensity and Wavelength on the Rate of Photosynthesis

In this simulation, you will be manipulating two variables: light intensity and light wavelength. The amount of ATP produced will change depending upon the set parameters. Go to "Johnson Explorations: Photosynthesis" located at http://www.mhhe.com/biosci/genbio/biolink/j_explorations/ch09expl.htm .

Procedure: Your task is to use the simulation to determine how wavelength and intensity affect the rate of photosynthesis (and the production of ATP). Keep in mind you are dealing with two variables, so in order to determine absolutely how each factor affects photosynthesis, you must keep one variable constant while manipulating the other variable.

Lab Report must containt the following typed sections.

1. Introduction: Describe briefly the light dependent reactions and propose a hypothesis to answer the experimental question.

2. Data: Include data tables for the simulation. The tables must show clearly trends resulting from changes of intensity and changes of wavelenth. Multiple data tables would probably be best here. In Microsoft Word, use the "table" function to organize your data.

3. A graph showing how the percentage of ATP changed (Y axis) as a result of changes in wavelength and intensity (X axis). Two graphs would be best here. You may use Create A Graph to make your graphs, or use a spreadsheet or graphing program of your choice.

3. Conclusion: Use your data to answer the experimental question. Answer clearly how light wavelength affects the reaction, and how light intensity affects the reactions. Offer an explanation of the results, taking into account the principles of photosynthesis and the light reaction.

 Grading Rubric Poor (1 pts) Satisfactory (2 pts) Good ( 3 pts) Introduction Explanation of light dependent reaction lacking and/or hypothesis missing. Offers explanation of the reaction, some parts vague or incorrect. Hypothesis unclear or does not answer experimental question fully. Offers good explanation of the the light dependent reaction, includes how light is used to produce ATP and NADPH. Proposes hypothesis to answer experimental question. Data Variables not separated, data disorganized, trends not apparent. Organized, though trends are not obvious from the layout. Hard to read, taking some time to figure out. Well organized into tables, variables separated, data clearly shows trends Not enough data was taken to test variables A fair amount of data was taken, enough to show trends Enough data was taken to clearly show trends Graphs poorly labeled, difficult to read. Graphs missing some labels or incorrectly set up Graphs all labeled correctly, easy to read Conclusion Does not answer experimental question. Erroneous conclusion. Answers experimental question, data used to support argument unclear, or partially incorrect analysis Answers experimental question, follows data, conclusions are not erred. Explanation attempted, but fails to explain data trends Explanation is reasonable, but does not take into account important aspects of photosynthesis Explanation for results is reasonable and takes into account principles of photosynthesis Format Not typed, not neat Typed, neat Total: ______ out of 20