Writing Laboratory Reports
Delphine Masse, Wake Forest
University
Lab reports
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Objective: learn to report the results of a
scientific inquiry in a generally used format
Delphine Masse, Wake Forest
University
The parts of a lab report
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Title
Abstract
Introduction
Methods
Results
Discussion
Literature cited
Tables and Figures
Delphine Masse, Wake Forest
University
Title
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Describes your experiment
Specific topic
Mentions the organisms studied
Delphine Masse, Wake Forest
University
Abstract
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Last thing to write!
Usually < 200 words, summary of your whole
experiment (ie: summarizes every part of the
paper)
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About one sentence per section
Self explanatory & independent from paper
No abbreviations or citations
Delphine Masse, Wake Forest
University
Introduction
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Introduces the reader to your topic
Explains why the topic is of interest
Explains the main concepts necessary to understand
your experiment
States which organisms were used (with scientific
name)
Refers to literature
States your purpose & hypothesis
Explains how your experiment will address your
purpose
Delphine Masse, Wake Forest
University
Introduction : more specifically
1.
2.
3.
4.
5.
General statement introducing the topic
Why is this topic of interest ?
Explain all concepts necessary to understand what you did.
What is your purpose?
Hypothesis
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2.
3.
6.
7.
Includes the word “hypothesis” or “hypothesized”
States your dependant and independent variables
Gives rationale for your expectations
How are you going to test this? How do the variables
recorded reflect the phenomenon you want to measure?
Briefly mention the outcome of the experiment
Delphine Masse, Wake Forest
University
Hypothesis example
eg: "Since male B. splendens have to protect
fertilized eggs against predators, it was hypothesized
that the aggressiveness of males, measured by the
average number of displays per minute, would be
higher in the presence of eggs than in the absence
of eggs."
Note: this assumes that you explained the link between
displays and aggressiveness in the background
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Delphine Masse, Wake Forest
University
Methods
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Enough information so that the experiment can be repeated
(But: assumes the reader has basic lab knowledge)
Passive voice, past tense
Contains:
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Experimental setup:
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Measurements taken:
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Specific: Durations, Concentrations, Voltages, quantities
Order in which things were performed
Emphasize how the experimental groups differ from the controls.
What did you record, how? In case you transformed data (eg. Used
percentages…), why?
Analysis Methods used:
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What type of statistics were used, why, and to compare what groups.
Delphine Masse, Wake Forest
University
Methods - Examples:
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“0.5 mL of 10-6M Muristerone in water were
added drop by drop to each of the four vials
in group 2.”
Delphine Masse, Wake Forest
University
Methods – examples: stats
Not-so-good : "A t-test was calculated for
the number of tail beatings” 
ambiguous!
BETTER: "A student's t-test was used to
compare the number of tail beatings in
male B. splendens with the number of
tail beatings in female B. splendens."
Dependant
variable
(outcome)
Test used
First group of
data points
Second
group of data
points
Delphine Masse, Wake Forest
University
Results
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Presents your results
Past tense
NO INTERPRETATION!
Text: talks about trends & comparisons. Refers to
figures &/or tables.
Backs up statements with results from statistical
analysis – include the p-values (that is what the text
refers to as “state if your hypothesis was supported”)
Delphine Masse, Wake Forest
University
Reporting results - Examples:
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The root:shoot ratio of plants grown in low-nutrient
soil was significantly lower than the root:shoot ratio
of the control (p = 0.03).
The number of tail beatings in male B. splendens
was significantly different from the number of tail
beatings in females (p < 0.05).
The root:shoot ratio of plants grown in low-nutrient
soil was greater than, though not significantly
different from, the root:shoot ratio of the control (p =
0.07).
Delphine Masse, Wake Forest
University
Discussion
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Goal: Interpretation of data
Addresses all the results presented before – and
no new results (do not repeat the results)
States your conclusions and your rationale (with
your evidence + data from other research)
Forms or refines hypotheses
Puts your results into a larger context
Delphine Masse, Wake Forest
University
Discussion – questions to cover
1)
2)
Did the data correspond to what you
expected? Why or why not?
Did the data correspond to what other
people found? (use citations here)
1)
2)
3)
If no, why do you think it happened? Present a
new hypothesis
If yes, are there other factors that may have
caused this outcome?
Finish on further research / implications
Delphine Masse, Wake Forest
University
Literature cited
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CBE format: see manual.
5 refs, incl. 3 journal articles, required.
In the text:
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Always paraphrase (no direct quotes)
(Jones 2003)
Eg: Methoprene has been shown to significantly
affect the development of Drosophila
melanogaster (Jones 2003).
Or: Jones (2003) has found that ……
Delphine Masse, Wake Forest
University
Literature cited (cont.)
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Some special cases:
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Anonymous : Use a short version of the title
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In text: (Lab. Manual 2003)
Reference: _________. Spring 2004. Comparative
physiology Laboratory Manual. Dept. Biology, Wake
Forest University, Winston-Salem, NC.
Paper you accessed online:
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Cite the print version NOT the database
Delphine Masse, Wake Forest
University
Tables and Figures
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Present summary data (no raw data!)
Tables then Figures
Number tables and figures independently, in
the order that they are mentioned in the text
All tables and figures should be mentioned in
the text
Delphine Masse, Wake Forest
University
Tables - Example
Table 1. P-values obtained when comparing Root:Shoot ratios of the different
groups using a Student's t-test
Delphine Masse, Wake Forest
University
Figures - Example
Figure 1. Average resting blood pressure (mmHg) of a group of 15
undergraduates and a group of 15 graduate students. Error
bars represent +/- SD for each group.
Delphine Masse, Wake Forest
University
General format issues
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Numbers:
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If <1, always have a 0 in front : eg. 0.1 not .1
If <5 and no units then spell it out; >5 use number
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Eg: a group of four vials; a total of 12 vials
Format: 1’’ margins, double spaced, 3 pages
of text, 1 of figures (references can be on a
separate page); Times 11 pt.
Delphine Masse, Wake Forest
University
Extra requirements:
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Attach to the report a printout of
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Your raw data, correctly arranged and labeled.
The outputs for the statistical tests you did with
Excel, correctly labeled.
The first page of each scientific paper you cited.
Do not mention these attachments in the
text. These are just for verification purposes.
Delphine Masse, Wake Forest
University