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Writing Lab Reports

Have you been assigned to write a lab report, but aren't sure where to start? Here are some resources that will help you understand what a lab report is, and how to format and write one properly.

What is a Lab Report?

A lab report is a document which describes a scientific experiment. It provides a formal record of the a hypothesis and the methods and outcomes of the experiment, using clear, precise language. Enough detail should be given to allow the reader to replicate the experiment if desired. The typical lab report follows the format described below, and has most or all of the components listed. Most importantly, a properly written lab report not only presents the data, it also demonstrates the writer's understanding of the data, results, and concepts, and the principles behind them.

There may be alternate requirements or formatting styles for different courses, so always ensure that you are following your instructor's directions when writing your lab reports.

Lab Report Components

1. Title Page

     This is the front page of the document. It gives the title of the experiment, the name(s) of the experimenters, the date, and the course the report was written for (if applicable). Titles should be descriptive but efficient and straightforward, telling the reader precisely what the report is about. Extraneous words and informal language should be avoided.

Example of a Good Title

     "The Effects of LED and Fluorescent Lighting on the Growth Rate of Red-Leaf Lettuce (L. sativa)": Describes the factors being manipulated (types of lighting), the parameter being measured (growth rate), and the subject of the experiment (red leaf lettuce; the scientific name is also given for specificity).

Examples of a Poor Title

     "Physics 110 Lab Experiment #3": This title lacks description of the experiment, so the reader has no idea what the report is about.

     "Different Ways to Find the Caffeine Content of Coffee Beans": Does not provide enough information, and uses unscientific and informal language.


2. Abstract

     The abstract is a condensed version of the report, containing all the most pertinent information in the document. It should be short, usually no more than 200-250 words. It must summarize the hypothesis or the reason for conducting the experiment, the methodology and materials used, the results and the major conclusion or conclusions. 

Tip

     Write the abstract last. Once you have written your report, you can more easily identify the required information and use it to build a good, comprehensive abstract.


3. Introduction

     In this section, you present the objective of your experiment and/or your hypothesis (why did you do this experiment? What problem are you trying to solve?), and give the reader the background information, such as relevant theories, necessary to understand your experiment. In order to do this, you may need to refer briefly to the literature on the topic. You may use such resources your textbook, journal articles, or books. If you do this, make sure to properly cite your sources!


4. Materials and Methods OR Procedures

     This section may be called either "Materials and Methods" or "Procedures", but in either case, the content is the same. Here you describe the methodology of your experiment: what you did and what materials you used to do it. It's important that you be very detailed in your descriptions so that the reader could replicate your experiment. Be sure to include information such as exact measurements, temperatures, and timing. You do not need to provide a list of all materials used (unless you are specifically asked to do so), but in the course of your narrative you should mention any tools, equipment, or specimens you used.

Tip

     When discussing the experiment, use the past tense, since the experiment has been completed. When discussing theories, laws, or established procedure, use the present tense. Lab reports are generally written using third-person passive voice ("Four soil samples were prepared") rather than first person active voice ("I prepared four soil samples"), but first person voice may be acceptable. Check with your instructor if you are unsure.


5. Results

     Now it's time to present the results of your experiment. What data did you gather? Did anything unexpected happen, or did anything go wrong? Usually, tables and graphs are used to present data in a more concise manner, but they must be accompanied by text as well. Even if you suspect something may have gone wrong with your experiment, report your results just as you gathered them. If the experiment relies heavily on calculations, you may be asked to add a separate section or appendix for these, but these are not part of a standard lab report.


6. Discussion

     Here is where you show your understanding of your experiment. Use this section to describe your observations during the experiment, and discuss your findings in relation to your hypothesis and to the literature referenced in the Abstract. If the experiment failed or you experienced problems during the experiment, discuss what might have caused this, and how it might be rectified in future experiments. You may also raise any questions that are suggested by the results, and discuss how these questions might be answered.


7. Conclusion

     In this final section, you should concisely summarize your findings. State what your results mean and how they relate to or answer your initial question or hypothesis.


8. References

      Here you cite any sources you used in the experiment. These should be full citations, using the citation style recommended by your professor (if your professor does not require a particular style, you may use a style that is commonly accepted in your discipline). Resources for how to create citations can be found here. If you have any questions about proper citation, contact your liaison librarian.

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Dana Ingalls
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