Writing a Laboratory Report in Biology
Hallmarks of Scientific Writing
An except from A Student Handbook for Writing in Biology by Karin Knisely
“What distinguishes scientific writing from other kinds of writing? One difference is motive. Scientific
writing aims to inform rather than to entertain the reader. The reader is typically a fellow scientist who
intends to use this information, for example, to learn more about a process or to improve a product.
A second difference is the style. Brevity, a standard format, and proper use of grammar and punctuation
are the hallmarks of well-written scientific papers. The authors have something important to
communicate, and they want to make sure that others understand the significance of their work. Flowery
language and “stream of consciousness” prose are not appropriate in scientific writing because they can
obscure the writer’s intended meaning.
A third difference between scientific and other types of writing is the tone. Scientific writing is factual
and objective. The writer presents information without emotion and without editorializing.” (p. 20-21)
Lab Report: Format
Your lab report should be organized into the following sections:
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Introduction
Hypothesis and Rationale
Prediction
Materials and Methods
Results
Discussion
References
The Cover Page should include a title and all members of the lab group. The title should be a concise,
informative description of what the lab report is about. All group members (first and last name) who
designed and/or participated in the experiment should be listed.
I. INTRODUCTION
The Introduction has three purposes. It should identify what motivated the investigation, how the
investigation fits into the existing body of knowledge, and it should state the objectives of the
investigation.
The first and second paragraph of the introduction should be dedicated to explaining what motivated
the investigation and relating it to the existing body of knowledge on the topic. Inconsistencies,
unanswered questions, or new questions that arise from previous studies set the stage for the present
investigation. Often research must be conducted to collect relative background knowledge on
topics/concepts to the investigation.
Improving your research skills is essential to your development as a student and writer. There is an
abundance of information available in literature and on the Internet. Sources can be classified into two
categories: primary sources and secondary sources. Primary sources include journal articles,
dissertations, technical reports, or conference papers in which a scientist describes his or her original
work. These sources have been written purposely for the scientific community. From reading a primary
reference members of the scientific community can duplicate the research for their own purpose, check
the validity of the reported findings, or develop new hypotheses upon the reported finding. Secondary
sources are encyclopedias, textbooks, and articles in popular magazines. These sources are based on
primary references but include less technical reporting on methodology and data. Secondary sources are
written for the general audience who are not trained as scientists. As a young scientist secondary sources
are a good starting point from which to conduct research. Since secondary sources are based on primary
sources, examine the literature’s reference section to identify the primary sources used.
Remember the first and second paragraph of the introduction should be dedicated to explaining what
motivated the investigation and relating it to the existing body of knowledge on the topic. For the
carbohydrate formal lab report, select ONE area of focus and conduct research. Use your research to
write the first two paragraphs of your report.
Research Focus Areas:
 Nutrition and carbohydrates (diet perspective)
 Photosynthesis and carbohydrates
 Chemical indicators and carbohydrates (how do iodine and benedicts work)
 Digestion and carbohydrates
The third paragraph of the introduction is a statement(s) of the purposes of the investigation. Reexamine the laboratory exercise you performed in class and determine what the goals of investigation
were. Through your writing you should demonstrate an understanding of laboratory goals and objectives.
II. HYPOTHESIS and RATIONALE
The Hypothesis section of the report should concisely state the testable explanation for the initial
problem or observation. In the carbohydrate report identify which food items you hypothesized were
monosaccharides, disaccharides, and polysaccharides. Then state your rationale for classifying the foods
as you did.
III. PREDICTION
The Prediction section of the report should be written as an “If…then…” statement. The “if” portion is
the stated hypothesis, and the “then” portion is what is predicted to occur if the hypothesis is true. In the
carbohydrate lab write your eight predictions in list form. For example:
1. If table sugar is a disaccharide, then a negative result will occur in the benedicts and iodine tests.
IV. MATERIALS AND METHODS
The Materials and Methods section describes what was done in the investigation. This is stated in full
sentences and well developed paragraph(s). Enough detail is used to allow the reader to replicate the
work. Generally known laboratory procedures do not need to be described however experimental
conditions involving volume, mass, concentration, pH, growth conditions, and temperature are items that
need to be included.
V. RESULTS
The Results section of the laboratory report summarizes the findings of the experiment. The findings are
NOT explained in this section; they are only stated. The results section has two components: (Knisely,
p.21)
 A text (written word) section which forms the body of the section that states the results.
 A visual that illustrates the data that was recorded. This can include a data table or graph.
For the carbohydrate report, create in Word and embed Table 3 from the lab procedure
as your visual.
VI. DISCUSSION
The Discussion section of the report analyzes and interprets the results. Possible explanations are
provided as well. The following are also included in the discussion section: (Knisely, p.21)
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Statement on results that identifies if the hypotheses/predictions were supported, refuted, or not
conclusively shown. Avoid using the term “prove”.
For example,
Faulty: These results prove that my hypothesis is correct.
Revised: The results provide support for the stated hypothesis.
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(Discussion continued)
Description of how the results relate to existing knowledge.
 For the carbohydrate report, choose 4 of the following food items from the lab (pancake mix,
Rice Krispies, apple juice, powdered sugar, rye bread, pasta (Barilla), and whole milk) and
research what is in them. Identify the ingredients that are carbohydrates and identify if those
carbohydrates are mono-, di-, or polysaccharides. Consider this research in light of your
experimental results.
Identify outliers in the data or unexpected results that do not match your research. Do not hide
inconsistencies in your data.
Describe possible sources of error that could account for inaccuracies.
Discuss new ideas, hypotheses, or extensions to the current investigation.
VII.
REFERENCES
The Reference section should be a list of the primary and secondary sources that that were used to gather
background information or from which citations were taken. This should be typed using the proper APA
or MLA style.
Lab Report: Writing Style
Each section (except the hypothesis and prediction sections) should include full sentences and welldeveloped paragraphs. Each section (except the introduction) should be written in the past tense because
the investigation has already been completed. In addition the passive voice should be used throughout
the report. For example:
Active Voice: I peeled and homogenized the potatoes.
Passive Voice: The potatoes were peeled and homogenized.
Active Voice: I concluded from this observation that…
Passive Voice: It was concluded from this observation that…
When you write your lab report it is suggested that you write the Introduction section last. Develop and
write all the other sections first before synthesizing your introduction. The idea is that you are now
familiar with your methods, results, and conclusions and you can keep your investigation in perspective
as you describe what is already known about the topic. Remember the Introduction has three purposes:
to identify what motivated the investigation, to demonstrate how your investigation fits into the existing
body of knowledge, and to state the objectives of the investigation. You can address existing
inconsistencies given the existing body of knowledge, and you can address unanswered questions that
previous research has not answered.
The guidelines outlined above can be located in:
Knisely, K. 2005. A Student Handbook for Writing in Biology, 2nd ed. Sunderland, MA: Sinauer
Associates, Inc. 237 p.
Lab Report: General Formatting
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Times New Roman 12pt
Double spaced text
Print on only one side of paper
Section headings in bold and CAPITAL letters; aligned left
Margins- top/bottom no larger than 1 inch, sides no larger than 1.25 inches