Information on how to Write a Lab Report
What it's All About?
As a student your understanding of physics or science, and your ability to design, conduct, and
communicate the results of an experiment is the focus of the evaluation. Your final product will be
a formal lab report written much like a research report that one might find in a scientific journal or
magazine*. This report will communicate your purpose, background understanding, procedure and
findings, and conclusions. This report must be written as concisely and clearly as possible so that
the reader can grasp the material quickly and could accurately repeat or expand on your research.
The formal lab report is thus, the critical document which reflects your success. For this reason, it is
important that you understand exactly what should be included in the formal lab report and how it
should be put together.
What should the Lab Report be Like - A Term Paper or an Essay?
a. Grammar is important. If you use computer grammar checkers, be aware that they are
probably not yet able to handle scientific style. Notice especially subject/verb agreement
and pronoun/antecedent agreement.
b. Spelling is important. Use spell check, but be aware that most spelling checkers do not
include many scientific terms. Copy unfamiliar terms with great care. A few letters can
make a big difference in a scientific term.
c. Accuracy is important. If your report says something you did not intend, then either you did
not understand what you were doing, or your reader will not know what you were doing (or
both).
d. Clarity is important. Do not assume that science (or an essay topic) is too complicated for
you to understand. If you do not understand what you have written, then no one else will
understand your report either. If you have filled your report with scientific terms and
complicated sentences in order to sound sophisticated, then you have probably succeeded
only in sounding muddled.
e. In a Science Lab Report, pack sentences with information. Add adjectives, adverbs, and
prepositional phrases to increase the amount of specific information.
f. In most writing, the active voice is preferred. For some aspects of scientific writing, active
voice is also preferred as it is less wordy and usually clearer.
g. A Science Lab Report is not creative writing. Stay within the limits of your study or
experiment.
h. A Science Lab Report follows a format using subtopics or sections to distinguish
expectations, results, the meaning of the results, those aspects that are controlled by the
researcher, and those aspects that are a result of the activity.
Lab Organization and Content:
• Title Page
•
Introduction
•
Experiment
•
Results: Calculations, Tables and Figures
•
Discussion and Conclusion: Discussion of Results
These sections should be clearly titled and organized in the exact manner as listed above.
Section Exposition:
Title Page - includes a meaningful title for your lab report, your name and that of your lab
partner(s).
Introduction:
A series of paragraphs in which you describe the scientific principles which you are modeling and
explicitly state the goal of your investigation; the purpose should be clearly stated. The introduction
should identify the basic scientific principals and give background information (historical and/or
theoretical) along with a what-if question. A good guideline is to include the phrase "we will
investigate the effect of ____________ (some controllable and modifiable variable) upon the
____________ (a measurable variable)." Procedural steps should not be discussed in the purpose
section. The introduction should end with a purpose statement (sometimes in the form of a
hypothesis or null hypothesis): one sentence which specifically states the question your experiment
was designed to answer. e. g. The purpose of this investigation was to determine the effects of
gravity on a pendulum swing in the presence of resistive air resistance. (as a purpose statement) or
The hypothesis was that current moving in a conductive material will generate a magnetic field
around that material (as a hypothesis)
Experiment:
In this section you will describe in narrative form, how you did the experiment, including
experimental design (picture of experimental set up), methods of gathering and analyzing data, and
types of control. This section must include complete details and be written clearly enough to allow
readers to duplicate the experiment if they wish. This section is written in past tense because you
have already done the experiment. It should not be written in the form of instructions or as a list of
materials as in a laboratory manual. Again, it is written as a narrative describing, either in first
person active voice or in passive voice, what you did. e.g., (first person active voice) I filled six
petri plates with agar. (Passive voice) Six petri plates were filled with agar.
Results:
In the section we are to find your observations, data (with no interpretations or conclusions about
what they mean), Tables and graphs. Raw data will probably be most effective in table format, with
the highlights summarized in graph form. Your data should be recorded in a neat and orderly
fashion. You will be provided data sheets for selected experiments (as found from the handouts).
You must include the units of measurement on your data sheets and throughout your calculations
and data recordings. Once again, the interpretation of your data and interpretation of any statistical
test applied to the data should appear in the Discussion and Conclusion section. Please Note: It is
ESSENTIAL that you accurately report your findings and not manufacture data to fit
preconceptions. "The greatest advances in science occur when a careful researcher gets
reproducible data which conflict with accepted notions". You will be graded on how you analyze
and interpret your data not on whether it agrees with your expectations.
Discussion and Conclusion:
This section reports the importance of your results. This is where you discuss your analysis and
interpretations of your results. Explain what you think your data means. Further, discuss how any
changes to or problems with the experimental procedure may have affected the results. Did your
data confirm or conflict with your initial expectations? What were possible sources of error? How
did this error change the expected results? Be particularly specific in answering this last question
by stating how the results change and in what manner they changed. Sometimes results do not turn
out as you expect. Describe patterns and relationships that emerged. Compare your results to that of
other members of your class. Propose a mechanism to account for any strange results.
Interpretations should be supported whenever possible by references to the lab handout, your text,
and/or other studies from the literature, or books that can be properly documented. Comment on
and discuss the relationship portrayed by any plotted data from the Results section. Do not merely
restate your data section; rather, make generalizations - e.g., "as the initial velocity is doubled, the
stopping distance increases by a factor of approximately four." Since you have plotted data, state
the equation which describes the data and discuss its significance. Use a paragraph to discuss any
errors which might have been associated with your experimentation and to make some
suggestions which would improve the actual experimental procedure. If your lab handout includes
questions to be answered, integrate your responses into a logical discussion in this section, rather
than answering them one by one. Do not spend enormous amounts of time explaining data that
cannot be explained! Most importantly, you should offer "supported" statements or what was
determined from doing the experiment. In other words, tell me what your conclusions were with
supporting evidence confirming your beliefs.
Common Errors and Pitfalls to Avoid:
There are a number of errors, which are commonly made, that you would be wise to avoid. Such
errors include the following:
Failure to write a formal lab report:
Failure to label the sections of the lab report such that it is not clear whether a given part of it is
reporting on the procedure, the data or the conclusions Tendency to place procedural statements in
the purpose (e.g., "we will then measure the photo gate time at point A and calculate the speed,
repeating the measurements three times to insure accuracy") and in the Conclusion section (e.g.,
"we measured the photo gate time and calculated the instantaneous speed and then found the kinetic
energy and total mechanical energy..."). Failure to write a solid and lengthy theoretical background
and tendency to merely state a short hypothesis (e.g., "we believe that the higher the initial height,
the greater the speed at point B."). The theory should be a lengthy section in which you
demonstrate that you know how a wealth of physics applies to your chosen scenario. Failure to
include a detailed procedure would provide sufficient direction for anyone to follow. The steps
should be included in a narrative form where there is enough detail for a person who is unfamiliar
with the equipment to conduct the same study. Tendency to use the first person in the procedure
section - "I then placed selected the rectangle tool. Then I drew a box by dragging on the screen. I
then ..." Tendency to merely restate your measured data in the Discussion and Conclusion section
(e.g., "we measured the photo gate times to be 0.0125 s when the height was 0.5 m and we
measured the time to be 0.008 s when the height was 0.15 m").
Tendency to make very general conclusions which (while perhaps true) have nothing to do with the
idea behind the lab report (e.g., "This project was fun and we learned a lot. We hope that we can
do more projects like this."). In general, all of these errors and pitfalls are usually the result of
either not following this lab report writing procedure or writing the lab at the last minute (which
subsequently leads to a tendency to not follow directions). Therefore, give yourself plenty of time
and take the time and effort needed to be acquainted with these guidelines described herein.