Name _____________ Period ____Date _______
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.
Experimental Question (write it here):_______________________________
Materials: Colored pencils, graph paper, laptop, Firefox
Lab Report must contain the following sections.
1. Introduction: a. Describe briefly the light dependent reactions and b. write
your hypothesis here to answer the experimental question:
a. Light dependent reactions:
_______________________________________________________
_______________________________________________
b. Hypothesis ___________________________________________
____________________________________________________
2. KEY: Draw a colored key here representing each of the chemical components
from the simulation.
3. Data: You will make 2 data tables on graph paper. Leave room for your 2 graphs.
What are the independent and dependent variables for each table? Write the
variables here:
4. Graphs: Draw one graph showing how the percentage of ATP changed (Y axis)
as a result of changes in wavelength and one graph showing intensity (X axis).
Don’t forget to label all axes properly and use color. What type of graph will
you use _______________. Why? ___________________________
5. 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.
6. Turn in for full credit: 3 things: This worksheet with all prompts answered on
it, data tables and graphs on graph paper, your conclusion on a separate piece of
paper.
Grading Rubric
Component Missing or
doesn’t meet criteria (0
points)
Poor (1 pts)
Satisfactory (2 pts)
Good ( 3 pts)
Introductions
Missing
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
Incomplete data tables
or missing 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. Fair
amount of data taken.
Well organized into tables, variables
separated, data clearly shows trends.
Enough data to clearly show trends.
Graphs
1 or 2 graphs missing
Graphs poorly labeled,
difficult to read
incorrectly set up,
sloppy, colorful key
missing, axes sloppy
Graphs missing some labels
or incorrectly set up, colorful
key included, ruler used to
place axes
Graphs all labeled correctly, easy to read,
colorful, correct type used, colorful key
included, ruler used to place axes
Conclusion
Missing, or fails to
address at least half of
conclusion prompts.
Does not answer
experimental question.
Addresses half of
conclusion prompts.
Explanation
attempted, but fails to
explain data trends
Answers experimental
question, data used to
support argument unclear, or
partially incorrect analysis.
Explanation is reasonable,
but does not take into
account important aspects of
photosynthesis
Answers experimental question, follows
data, conclusion prompt answered,
conclusions are correct. Explanation for
results is reasonable and takes into
account principles of photosynthesis
Sloppy, hard to read,
run-on sentences
Neat handwriting, easy to
read. Mostly proper spelling
and punctuation.
Format
Total: ______ out of 20