Writing Support Services, Student Success Centre
ucalgary.ca/ssc/writing-support
Writing an Undergraduate Lab Report
Lab reports are a means of communicating experimental findings. They summarize experiments,
present observations, show results, and draw conclusions. The specific structure of the lab report
may vary between departments or instructors, so verify the structure required for your course. This
handout provides the basic structure of lab reports, and tips to help you become comfortable with
scientific writing.
Developing Your Scientific Voice
One of the challenges for novice lab writers is capturing the scientific voice. Consider the following
three tips:
1. Avoid using the first or second person.
Your report should be written in the third person. Whenever possible, I, me, my, we, us, and
our should be avoided because facts and observations are independent of those who
observe or present them.
i.e. The chemical is heated. not I heat the chemical.
2. Write in the present tense.
Lab reports are written in the present tense, even if the experiment occurred in the past.
i.e. 50 mL of HCl is added. not 50 mL of HCl was added.
3. Be clear, concise, and objective.
Your language should be to the point and effective. Avoid including unnecessary words,
redundant explanations, or vague expressions of quantity. Do not use a little, a lot, slightly,
greatly, etc. They are not quantifiable.
i.e. Two strips of magnesium are
not
Two strips of magnesium metal that had
added to the 100 mL beaker
been obtained from the supply cupboard
and the solution is stirred.
are added into the 100 mL glass beaker
that is labeled A, and the solution is
stirred using a glass rod from the lab
bench.
i.e. 75% of the cells are in the first
phase of mitosis.
not
A lot of cells are in the first phase of
mitosis.
Structuring Your Report
Introduction
The introduction includes the purpose of the experiment, a description of how the information is
obtained, and background information about the topic (including pertinent equations or reactions).
Only include information that is needed to understand your report; don’t go overboard. This
information should be obtained from peer-reviewed sources, such as journal articles.
Materials and Methods/Procedures
In this section, list all the equipment and materials used to complete the experiment, as well as a
step-by-step summary of the method. Ask your instructor whether you’re allowed to reference the lab
manual instead of having to copy all of that information into your report. Do not copy the method,
however, from the lab manual word for word; this is plagiarism. If you have added or removed any
steps in the procedure, note these changes in your report.
Observations
The observation section presents what you saw, heard, or recorded without any interpretation. Be
sure to include all observations. Noting that a solution was clear and colourless may seem trivial, but
it must be included. All observations of temperature, volumes, concentrations, and masses must be
presented with units, such as mol/L. Use tables to organize observations whenever possible.
Revised November 2013
2
Sometimes, this section of the lab report is combined with the results section, so check with your
instructor.
Results
The results section is an interpretation of your observations and may include calculations and
graphs. You may only be required to include sample calculations; check with your instructor.
Summarize your findings in tables whenever possible; tabular results are easier to read and
interpret. This section should not include a lengthy explanation of the results (do this in the
discussion); simply show how you have analyzed your observations to arrive at your conclusions.
Discussion
In this section, briefly explain the procedure of the experiment. This should not be a step-by-step
description. Next, analyze and interpret your results and discuss their significance. Explain whether
your results were expected or unexpected using the concepts and theories you discussed in your
introduction. Lastly, compare your findings to references if possible. Explain deviations and list
possible sources of error. Human error does not qualify! Spilled chemicals or contamination from lab
work are not considered causes of erroneous results.
Conclusion
In the conclusion, briefly summarize your results and their significance. Restate the purpose and
objectives of your experiment and whether or not they were achieved. Do not interpret results in this
section (you did this in the discussion).
References
A well-written lab report should include references to external sources (particularly in the introduction
and discussion). Include a reference section in your report that cites all resources used. Ask your
instructor about the preferred citation style. Don’t forget, borrowing ideas from an external source
without citing is considered plagiarism and is a serious academic offence.
The DOs and DON’Ts of Lab Report Writing
DO
Write in the third person, in the present tense.
Use scientific language.
Be clear and concise.
Remain objective.
Use quantifiable expressions of quantity.
Reword information taken from the lab manual.
Include all observations seen, heard, or felt.
Present observations in tables when possible.
Summarize your procedure in the discussion.
Interpret your results and support them using theories
and concepts.
Explain any deviations from literature values, and cite
possible sources of error.
Summarize your findings in the conclusion.
Include references to all external sources and cite them
in your reference list.
DON’T
Write in first or second person, or in past tense.
Use slang or jargon.
Include unnecessary words and expressions.
Include your personal opinions.
Use unquantifiable expressions (i.e. a little).
Copy directly from the lab manual.
Record what you think you should see.
Interpret findings in the observations section.
Give a step-by-step method in the discussion.
Fabricate conclusions, or use results you think you
should find.
Cite sloppiness or carelessness as sources of error.
Interpret results in your conclusion.
Plagiarize sources, or include information in your report
that you do not cite.
3