Sara Lorenz and Julianne Sachs
Guidelines for Writing a
Traditional Lab Report
Overview
The goal of any scientific report or publication is to document experimental
findings and communicate their significance. Publication of experimental
results is one of the primary methods that scientist use to communicate new
discoveries.
To the Student…
A quality report will do more than present data, it will require in depth thought
and detail about experiment and demonstrate your comprehension of the
chemical concepts behind the data. Therefore, simply reporting the expected
and observed results is inadequate. In this report you should attempt identify
how and why differences occurred, explain how they affected the experiment,
and clearly answer the hypothesis that the experiment was designed to examine.
In addition to understanding the chemical concepts behind the experiment,
clear thinking and organized writing are just as important. No matter how
convincing your evidence might be, your experiment will not be taken seriously
unless you are able to communicate your findings in a concise manner. In this
report you will need to organize ideas carefully and express them coherently.
General Lab Report Format
Think of this laboratory report as a scientific essay that contains the following
sections:
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Title
Purpose
Procedure
Data
Results
Discussion
Conclusion
Sara Lorenz and Julianne Sachs
A brief description of what each section should include is provided below:
TITLE: The title should summarize, as specifically as possible, the subject of
the lab.
PURPOSE: A single, concise statement of the major objective(s) of the lab
that answers one of the following: What question or questions is this lab
exercise designed to answer? What is this lab exercise designed to show or
prove? What hypothesis is this lab exercise trying to prove or disprove?
Note: To make a hypothesis, you must be able to provide support for that
hypothesis, based upon your knowledge or literature research. A hypothesis
should be an EDUCATED prediction!
PROCEDURE: Include the information necessary to allow someone to repeat
what you did:
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Include definitions of key terms and anything else necessary to
understand exactly what was done.
Include a summary (not step by step procedure) of how samples were
prepared and how data was collected.
What data was used? Include information about the data such as the data
source (i.e. Internet, observations, models)
DATA: This is a record of all measurements and other observations
encountered during the lab exercise.
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Present the data in a way that makes it easy to discuss and to infer
conclusions (Tables or graphs are often helpful!)
Graphs will sometimes be required or helpful. These should be drawn
with a computer. The horizontal axis should contain the independent
variable (the one that is known), and the vertical axis should contain the
dependent variable (the one that you are observing or measuring). Each
axis must be labeled. The graph must be titled. The intervals on each
axis must be consistent.
RESULTS: Should contain a summary of the final data, presented in a
form that is most useful for interpreting the results. A short paragraph is
sufficient. Remember to title all graphs and tables. The graphs and tables
should be comprehendible independently of their association with the text.
Sara Lorenz and Julianne Sachs
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Results are usually dominated by calculations, tables and figures;
however, you still need to state all significant results explicitly in verbal
form, (i.e. Using the linear equation, the concentration of the solution
was calculated to be…)
Graphics need to be clear, easily read, and labeled.
Number and title all tables and graphs.
An important strategy for making your results effective is to draw the
reader's attention to them with a sentence or two, so the reader has a
focus when reading the graph.
In most cases, providing a single sample calculation of each type is
sufficient in the lab report.
Be sure to point out trends and identify special features.
State your key result in sentence form.
DISCUSSION: This is the most important part of the lab, as it is where you
interpret your observations and results. For each conclusion you should discuss
its significance and whether or not it seems reasonable. In addition, be sure
that you answer any questions that were asked in the laboratory instructions.
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You should infer conclusions from your data. For each conclusion, you
should provide evidence from your data.
Give explanations for and implications of any relationships observed.
(When interpreting a graph, infer conclusions based upon the slope of
the line or equation of the line).
Support your ideas with specific references to the results of your
analyses. How do your observations lead to the conclusions you
reached?
Were the relationships what you expected from the underlying physical
principles? If a conclusion does not seem reasonable, can you find any
error in your procedure which could have affected your results?
For each conclusion you should discuss its significance. Address any
interesting questions you may have had as you were working through the
lab exercises. In addition, be sure that you answer any questions that
were asked in the laboratory instructions.
Can you make any generalizations? Why or why not?
CONCLUSION: Summarize your results, the main points of your discussion,
and how they relate to your stated purpose of the lab.
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You are to concisely restate all the conclusions that were made in the
discussion section.
Sara Lorenz and Julianne Sachs
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No discussion, explanation, speculation should occur in this section! (Do
not use the words "because" or "since" or "therefore".)
It is a good idea to include how the main points of your discussion are
connected in order to demonstrate the overall significance of your
findings and the concepts you learned.
Please do not tell me how much you enjoyed this experiment or how
much you learned from it. Just give your conclusions!
Additional Notes
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After the lab report is written:
1. Make sure your writing is clear. Read it aloud to yourself or a
friend, does it make sense?
2. Use the word processor spell-checker or a dictionary.
3. Check to be sure all pertinent plots, graphs, etc. are included.
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Note on verb tense:
1. The experiment is already finished. Use the past tense when
talking about the experiment. (i.e. The objective of the
experiment was...)
2. The report, the theory, and permanent equipment still exist;
therefore these get the present tense. (i.e. The purpose of this
report is...; The graphing calculator produces...; Boyle's Law
states...)
Sample Scoring Guide
Your lab report grade will depend on completeness, scientific accuracy
and insight, organization, and writing skills. Lab reports to be typed,
double spaced with numbered pages.
The point totals for each section are for a 100 point report.
1. Title. (5 points)
The title should summarize, as specifically as possible, the subject of the
lab.
Sara Lorenz and Julianne Sachs
2. Purpose. (5 points)
This section should put the experiment into context and provide the
reader with information necessary to understand the scientific basis of
the experiment and the techniques used.
3. Data (15 points)
This section should include all raw data, including units, and appropriate
graphs.
4. Discussion (15 points)
Discuss the experiment and the results obtained. This does not mean you
simply report the results again, but rather interpret and discuss their
significance. Include a section containing a summary of the final data,
presented in a form that is most useful for interpreting the results and
sample calculations of each type used. A short paragraph should be
sufficient, along with any relevant charts and graphs labeled well.
Remember to title and provide legends for all graphs and tables. The
graphs and tables should be comprehensible independently of their
association with the text. Significant results should also be stated
explicitly in verbal form. If problems were encountered during the
course of the experiment, how might they be rectified in the future? Are
there any other things we could do to make this a better experiment or to
more specifically address the initial question(s) posed? Are there any
better techniques available that would allow one to more accurately
generate data? Is there more than one way to explain the results? Your
results may support your initial hypothesis, but there may be more than
one conclusion that could be drawn from your results. Lastly, do not
spend enormous amounts of time explaining data that cannot be
explained!
5. Conclusion (5 points)
Summarize your results, the main points of your discussion, and how
they relate to your stated purpose of the lab. No discussion, explanation,
or speculation should appear in this section.
Sara Lorenz and Julianne Sachs
6. Reference Citations (5 points)
As required in all scientific literature, statements of fact, not considered
"common" knowledge, must be properly referenced. Give complete
citations of all literature cited in the report.
What's complete? Here are some examples:
Articles in Journals:
Marmur, J. 1961. A procedure for the isolation of deoxyribonucleic acid
from microorganisms.
J. Mol. Biol. 3:208-218.
Articles in Books:
Coakley, W.T., A.J. Bates and D. Lloyd. 1977. Disruption of bacterial
cells. p279-341. In A.H.
Rose and D.W. Tempest (ed.), Advances in Microbial Physiology, Vol.
16. Academic
Press, London and New York.
**This guideline has been adapted from: “http://www.wku.edu/3kinds/dmlabmain.html.”