Doyle Online Writing Lab

Laboratory Report Instructions

Table of Contents:

Parts of a Lab Report

  1. Title Page
  2. Abstract
  3. Introduction
  4. Materials and Methods
  5. Results (Text)
  6. Results (Figures and Table)
  7. Discussion
  8. References

Example of a well-written lab report
Example of a poorly written lab report

"Science is not an individual experience... an individual's knowledge properly enters the domain of science only after it is presented to others in such a fashion that they can independently judge its validity."

� On Being a Scientist, the National Academy of Sciences, 1995

Learning to communicate your work in a clear, consistent way using a standard format is part of becoming a scientist or a scientifically literate citizen. Science writing is more formulaic and repetitious than other types of writing. Varying word usage may be desirable in a Humanities paper, but scientists "reject the null hypothesis" with the same phrase every time. The different sections described below will overlap in content and should be understandable no matter what order they are read in. Reading the Figure legends and Table captions should give the reader enough information to be able to interpret the results for themselves.

Specific instructions will be given in each lab handout as to whether a full report or a partial report is due individually or with your lab group. The lab report is usually due in your lab section at 1:10pm one week after you perform the experiments. Print your report the night before it is due. Please do not turn in your report to anyone's mailbox. Talk to your lab instructor if circumstances beyond your control keep you from turning in a report on time.

Collaborative work is part of doing science. Group reports should follow these guidelines:

  • The # of authors must be <= the # of students that worked together in the lab.
  • Work together on the report to ensure consistency across sections.
  • DO NOT divide up the sections and meet at the stapler in lab when it is due.
  • DO NOT put someone's name on the report if they did not work on the report.
  • Each author is responsible for the quality of the entire report.

Do not ever represent parts of the textbook or ideas from the literature or other students' writing as your own. This practice, known as plagiarism, is an intellectual crime.

For more detailed information, refer to this book (copies available in labs B5 and B7)

McMillan, V.E. 1997. Writing Papers in the Biological Sciences. 3rd Edition. Bedford/St. Martin's, Boston.

and the American Chemical Society style guide.

When a complete laboratory report is requested, it should include:

1. Title Page

  • an informative report title
  • your full name(s)
  • a mailbox number for return
  • course number
  • date report turned in
  • laboratory instructor
  • laboratory day
  • signatures of each author indicating that they fully agree with its contents

2. Abstract

5-8 sentences arranged in one paragraph as follows:

  • the scientific context of your experiment
  • what you did (use active past tense)
  • how you did it (brief mention of the methods used)
  • what you found (state your results in qualitative terms)
  • what it means

3. Introduction

  • Background information so that a reader will understand the purpose of your experiments.
  • Italicize Latin binomials with the Genus name capitalized and the species name lower-case. (Homo sapiens) After the first use, it is OK to abbreviate the genus name (H. sapiens).
  • Discuss and cite specific experiments done by others if possible.
  • What are the questions you are asking, and why are they worth asking?
  • Explain the purpose of your experiments
  • Give a brief description of treatments used and what was measured.
  • State the null hypotheses and predictions being tested when appropriate.

4. Materials and Methods

This is not a list of materials used, but a combination of text and tables describing the procedures. A knowledgeable scientist should be able to repeat your experiments after reading this section.

  • Summarize the procedure that you performed in your own words using active past tense. This is especially important for deviations from the lab protocol.
  • Details like concentrations (in absolute units like mM, not 1x), temperatures, and sample size are important.
  • A Table is often useful here to describe the treatments.
  • Date, time, and location may be relevant for a field study, but are not usually needed for a lab experiment.
  • Any statistical analyses and software used for data analysis should be mentioned.

5. Results (text)

  • Describe your results (do not list actual numbers, but point out trends or important features). "Data" is the plural form of the noun "datum" (use "data are", not "data is").
  • Refer to all figures and tables by number as well as any other relevant information. "See Figures." is not sufficient.
  • Briefly interpret any analyses and state whether or not you can reject the null hypotheses or support specific predictions if appropriate.
  • Always report the direction of any significant difference or relationship. Which of your treatment groups was larger, greater, or faster? Was it a positive or negative regression slope?
  • The normally accepted format for reporting statistical results within text is to give the Test Name, Test Statistic, degrees of freedom or sample size, and P-value (e.g. Flower number was significantly higher for unherbivorized plants (ANOVA, F = 7.232, df = 2, 78, P = 0.0013).
  • Results are typically not discussed much more in this section unless brief discussion aids clarity or guides the reader through a series of results.
  • If you experienced technical difficulties, you must describe your expectations rather than your actual data or get raw data (not completed figures) from a classmate or the laboratory instructor (remember to cite their source).

6. Results (Figures and Tables)

  • Summarize your data in graphs or tables as appropriate. Do not repeat the same data in both a table and a graph. A graph is preferable.
    Do not simply list your raw data.
  • Graphs, diagrams, and photos are numbered consecutively as Figure 1 to Figure X.
  • Tables are numbered separately from the Figures as Table 1 to Table X.
  • The Table convention is to use columns for categories of information (i.e. size, shape, etc.) and rows for the different entries (i.e. species of bacteria).
  • Label the axes or columns and define all treatments including units (do not repeat units within the Table). Labels such as "treatments 1,2,3, and 4" are not sufficient.
  • Write informative Figure legends (text below the Figure) so that it is not necessary to refer back to the report to understand the Figure. Include information about methods (temperature, concentration), how the data are expressed, sample size, and any abbreviations.
  • Do not include any Results or Discussion in the legend.
  • Write informative Table captions (text above the Table) so that it is not necessary to refer back to the report to understand the Table. A caption presents a succinct statement of the contents of the table. The caption must NOT include information about methods, how the data are expressed, sample size, or any abbreviations; those are included as footnotes to the table, with each footnote keyed to a footnote reference in the table by sequential, lettered superscripts.
  • See report that follows for an example of Figure legends and Table captions and footnotes.

7. Discussion

  • Describe each general result very briefly. No need to refer to Tables, Figures, or P-Values.
  • Discuss any expected and unexpected findings in light of the hypotheses and predictions outlined in your introduction or the specific literature (cite references) which prompts your expectations.
  • Describe those technical factors that you believe might help the reader interpret your data.
  • Critique the experimental design. Does it adequately address the hypotheses being tested? Were there faulty assumptions in the design that confound your interpretation of the data?
  • What new questions are prompted by the results?
  • If your particular experiment failed, what would you do next time to make it work?
  • Include in your text answers to specific questions if listed in the laboratory handout. It is usually a good idea to reflect on these questions as you are obtaining your data.

8. References

  • Avoid the use of direct quotes. Paraphrase and cite the source instead.
  • Prepare a complete alphabetized (by first author's last name) list of references that you cited within your report.
  • Do not list at the end if not cited within the text of your report.
  • Do not cite in your report if not listed at the end.

For references, the laboratory handout is only a beginning. Seek out original sources, using the references given in laboratory as an entry into the primary literature (peer-reviewed journal articles). Rarely cite textbooks�not only is this d�class�, but information in textbooks is less reliable than in original sources. Use the library (especially the Science Citation Index) to find more detailed information on the topic.

In biology papers, information gleaned from the literature is usually paraphrased and the literature source cited by author(s) and date of publication, e.g.:

Mammalian eggs are generally rather small (Klassen and Black, 1974). Weikert et al. (1977) found that monotremes, however, lay large, yolky eggs.

Note that this referencing technique indicates that the information came from Klassen and Black's and Weikert et al.'s papers, but the statements are not direct quotes, which should be avoided. For more than two authors, et al. is used in the citation, but all authors are included in the reference list at the end.

Example reference formats:

Purves, W.K., D. Sadava, G.H. Orians, and H.C. Heller. 2004. Life: The Science of Biology, 7th Ed., Sinauer Asso., Inc., Sunderland, MA.

journal article:
Steinhardt, R. and D. Epel. 1974. Activation of sea-urchin eggs by a calcium ionophore. Proc. Natl. Acad. Sci. USA 71: 1915-1919.

chapter in edited book:
Edmunds, M. 1990. The evolution of cryptic coloration. Pp. 3-21 in D. L. Evans and J. O. Schmidt, eds. Insect Defenses: Adaptive Mechanisms and Strategies of Prey and Predators, State University of New York Press, Albany.