Lab Report on Photosynthesis
Biology 212
Winter 2005
Scientific writing
One of the objectives of the laboratory experience this term is to develop your writing
skills. In science, writing is an important means of communication. A scientific paper
usually includes the following parts: a title (statement of the question or problem), an
abstract (short summary of the paper), an introduction (background and significance of
the research, including any hypotheses and predictions), a materials and methods section
(report of exactly what you did), a results section (presentation of data), a discussion
section (interpretation and discussion of results), and references (books and periodicals
cited in the introduction or discussion sections).
Assignment
Write a lab report on your experiment investigating the effect of different wavelengths
of light on the rate of photosynthesis by Elodea. The report should be typed with doublespaced text and pages numbered with the following components:
Title (See http://www.wisc.edu/writing/Handbook/SciRep_Title.html)
Introduction This section gives the background and rationale for your research question.
In other words, it places your research in context. This introduction section includes your
research question, hypothesis, and prediction. The background and rationale information
should be no more than one page. You must give credit for any information that you gain
from other sources and present in your report by citing the reference. One reference is
required. (See http://www.wisc.edu/writing/Handbook/SciRep_Intro.html)
Methods Give a brief description of your experimental design (1-2 paragraphs), which
includes your independent and dependent variables and the number of replicates.
Results This section has two components: (1) text describing your results (1-2
paragraphs) and (2) a table or figure summarizing your data. The table or figure needs to
have a complete title. Cite your table or figure in the text portion of your report. Do not
interpret your results in this section. Review pages 14-18 in your lab manual for tips on
presenting and analyzing results. (See Lab Topic 1 Scientific Investigations in your lab
manual).
Discussion This section includes conclusions based on the results of experiment. Do the
results match your prediction, thus supporting your hypothesis? See guidelines for the
discussion section in your lab manual on page 751-758 (Appendix A). Note that the steps
listed on page 755-756 are to be used to prepare your discussion section. The actual
discussion section should be an integration of all the listed information into one or two
clear and concise paragraphs.
(http://www.wisc.edu/writing/Handbook/SciRep_Disc.html)
References You must give credit to any information that you gain from other sources
and that you present in your report. At least one reference is required. See resources
below for guidelines on citing references. References need to be listed in alphabetical
order by author’s last name.
No references from the Internet will be accepted for this assignment unless from an online peer reviewed scientific journal.
• How to decide what information must be referenced
http://www.wisc.edu/writing/Handbook/QPA_plagiarism.html
• How to write a successful summary without plagiarizing
http://www.wisc.edu/writing/Handbook/QuotingSources.html
http://www.wisc.edu/writing/Handbook/QuotingSources.html
• How to cite references
http://www.wisc.edu/writing/Handbook/DocCBE_NameYear_Intext.html
Additional Resources
• The Biology web site, http://osu.orst.edu/instruct/bi212/writew05.htm, has
information on resources for writing and library research.
• General information on writing a scientific report
Appendix A Scientific Writing in your lab manual.
• Evaluation form included with this assignment sheet.
• Be sure to talk with your Lab Instructor if you have any questions.
Due Date
Your Lab Instructor will assign the due date. The grade on late reports will decrease 5%
per day.
Evaluation
Your lab report will be evaluated on the content (4 points) and the effectiveness of your
communication, including text and figures (5 points). See the attached page for a sample
evaluation form.
Evaluation of Lab Report on Photosynthesis
Biology 212
Winter 2005
CONTENT
Title
Introduction
Background and rationale
Research question
Hypothesis
Prediction
Methods
Description of experimental design
Procedures
Results
Table or figure (graph)
Text describing results
Discussion
References
COMMUNICATION
Writing
Grammar, spelling, punctuation,
capitalization
Sentence construction
Paragraph structure: sentences in
logical order supporting one main
idea in each paragraph
Organization of paragraphs
Conciseness and clarity of writing
Table or figure
Each title tells a complete story
Organization of report
Headings and subheadings included
Double-space text
Pages Numbered
COMMENTS
Lab Report on Photosynthesis
Biology 212
Winter 2005
TAKE THIS PAGE HOME. Use the data to complete the writing assignment.
Question:
Hypothesis:
Prediction:
Procedures:
1. Assemble the manometer. Fill two test tubes completely with 1.5% sodium
bicarbonate. Take a piece of Elodea, make a fresh cut at the cut end, and, holding the test
tube over the sink or a pan, add the Elodea, stem end up, and the rubber stopper with the
syringe and graduated pipette to each test tube. The stoppers should displace the water so
that no air is inside the tubes. Cover one tube with aluminum foil. Cover the second
tube with colored cellophane.
2. Set the assembled manometers into a test tube rack.
3. Place the heat sink immediately adjacent to the manometer.
4. Using the meter stick, measure and place a piece of tape on the lab bench adjacent to
the heat sink 15 cm away from the heat sink.
5. Place the light source at the 15 cm mark.
6. Use the syringe in the stopper to set the starting point of the water at a mark on the
graduated pipette close to each test tube, the experimental and the control. Record the
initial pipette reading.
7. Turn on the light. Wait 15 minutes. Record the final pipette reading for each tube.
8. Using the syringe, readjust the starting pointing of the water to a mark close to each
test tube, and record the initial reading. (You may not need to readjust the control tube).
Results
1. Calculate the change in manometer reading for the control and experimental tubes by
subtracting the final reading from the initial reading (I-F). Record your results.
2. Calculate the corrected volume of oxygen produced at by subtracting the change in the
control tube (A) from the change in the experimental tube (B). Record your results.
3. Record the volume of oxygen produced as measured by other teams. Calculate the
total and mean, or average, for the class data.
4. Plots the class data on the graph.
Data:
TABLE 6.7 Experiment Two: Volume of Oxygen Produced from Elodea Exposed to
Different Wavelengths of Light (Investigative Exercise, Summary of class data)
Corrected Volume of Oxygen Produced
Replicate
Green
Red
Blue
All colors
1
2
3
Total:
Mean:
total/# teams