Basic Outline

Scientific writing can be in the form of a laboratory report, a thesis, a journal article, or some other written communication used to disseminate the results of scientific research. The exact format required depends upon the type of written communication and often will vary from source to source.


Preparation of a Laboratory Report

A lab report differs from a paper in that it has defined sections. The sections required vary from laboratory to laboratory but the standard outline for most lab reports in the biological science include: title, your name, purpose of the experiment, methods, results, discussion and conclusion, references. Some lab reports may include a section of questions that must be answered concerning the experiment. Most laboratory courses will require that data be immediately written into a lab notebook in pen. Some labs will require you to attach these data pages to your report. Normally a lab report should be typed, spell checked and proofread before being submitted.

When writing a thesis, article for publication, or a report to turn into your supervisor, your first draft will be reviewed by your mentor and/or co-workers and then undergo revision. No matter how good a writer is, most reports require some revision. It is best to write your first draft and then let it sit for a few days before you read it the next time. Many times you are too “close” to the material after the first writing to see obvious errors. (This has definitely been true of this document!)


Sections of a Laboratory Report

Title: The title should be concise and specific and tell the reader what you did

Purpose: Most lab reports do not include a formal introduction and instead substitute a purpose. The purpose of the experiment should be stated in one or two sentences. You should know the purpose of the experiment before you start.

Methods: Most lab reports do not include all the details a journal article requires. Normally the procedure can be listed and referenced to the appropriate laboratory manual pages. If modifications have been made to the methods in the lab manual, these need to be clearly described.

Results: All data and observations should be included in the lab book; however, what you think should have happened or the methods section are not included. Types of results may include:

  1. Measurements. Report measurements using standard metric units. Any time a number is presented, it must have units. Abbreviations of units are used without a following period. Use the prefixes m, m, n, and p for 10-3, 10-6, 10-9, and 10-12, respectively. Numbers should be written as numerals when they are greater than ten or when they are associated with measurements; for example, 8 mm or 20 g. In a list of objects including both numbers over and under ten, all numbers may be expressed as numerals. Example: 17 bacteria, 2 yeast, and 1 protozoan. If a number starts a sentence spell out the number, do not use a numeral. Example: ten mannitol salt agar plates were streaked…
  2. Calculations. The equation should be indicated. In a lab report, even if you use a calculator, you must set up the problem.
  3. Tables. Number each table and provide a title and legend that contains all the information needed to interpret the data. The reader should be able to understand the content without the text. The title should be located at the top of the table. Columns and rows should be labeled clearly. All notes should be placed below tables. Any abbreviations, units, calculations, or statistics used should be described in headers or footnotes (see Table 1 for an example). Symbols such as #, *, !; and superscripts such as 1 and 2 can be used to identify these footnotes. Use bold type to make these obvious.
  4. Figures. Figures include graphs, photographs, drawings, diagrams, maps, and all other illustrations. All figures should be numbered and have a title and legend that contains all the information needed to interpret the data. The reader should be able to understand the content without the text. Figures should be labeled at the bottom. For a graph, units are specified on the abscissa and ordinate. If the photograph is of an object under the microscope, the total magnification should be indicated. Photographs of gel electrophoresis data should include a number on each lane, and the legend (or the figure itself) should indicate the contents of each lane.
  5. Plate counts. Include results for all dilutions, even if they are too numerous to count (TNTC) or 0. You should indicate the type of medium plated and temperature of incubation. See Table 1.

Table 1. Results of viable cell count of diluted Escherichia coli grown at 37oC in nutrient broth (1 ml plated).

Dilution of culture Plate counts, colony forming units (CFU)/ml*
10-2 TNTC (>250), TNTC
10-3 249, 235
10-4 35, 23
10-5 3, 5

*In this example, only 249, 235 and 35 are significant counts. These data are averaged:

249/10-3 + 235/10-3 + 35/10-4 or 2.5 X 105 + 2.4 X 105 + 3.5 X 105/3

= 2.8 X 105 CFU/ml


The text should refer to each table and figure and they should appear after, but close to, text that refers to them, (i.e., at the end of a paragraph or section). Alternatively, tables and figures may be placed at the end of the paper. Tables and figures are numbered independently of each other, and they are assigned numbers in the order they are mentioned in the text. The in-text reference to a table or figure should not repeat the caption (e.g. ‘table 1 shows “Title on table” ’). Instead, it should draw attention to key features (e.g. “Table 1 shows that the number of bacteria in the culture increased markedly between hours 1 and 4.”).


Discussion/Conclusion: The discussion section interprets the meaning of the results and draws conclusions from the data that have been presented. The authors should show how their observations relate to each other to form a cohesive story. If data can be interpreted in more than one way, all possibilities should be mentioned and the authors should indicate which alternative they think is correct and why. Results should be discussed even if they are unexpected or negative. For example, the presence of unexpected bands on agarose gels should be explained. This section should also address any discrepancies between these results and other papers. Material obtained from another source should be referenced.

The meaning of your results should be summarized in two to three sentences at the end of the section. This includes the potential implications of the research, and possibilities for future research that would contribute more to the field. In lab reports, experiments do not always work. This section allows the researcher to explain what might have gone wrong with an experiment.


References: The reference section gives complete details about sources that were cited, in any section of the text. A "Bibliography," on the other hand, refers to a list of materials used to obtain background knowledge on a subject. There are several standard styles for listing references. Depending on what type of scientific writing you are doing, you may be directed to follow a particular format. If so, follow the format that has been specified exactly. When references are cited, either the reference number or the author’s last name and the publication year are used. Example: “Some strains of E. coli can grow in orange juice (1)…” or “Some strains of E. coli can grow in orange juice (Brown, 1999)….” In this class, we will use the reference style of the American Society for Microbiology Journals. When references are cited within the paper, only the number is used. References are numbered in the order in which they appear in the article (citation-sequence reference system). No reference should be included that is not cited in the paper. Remember that ALL information within the report that is not your original work or idea should be referenced. Statements by other authors are usually paraphrased or summarized – direct quotations are rare in scientific writing.

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