Lab Reports

This document describes a general format for Lab Reports that you can adapt as needed. Lab reports are the most frequent kind of document written in engineering and can count for as much as 25% of a course – yet little time or attention is devoted to how to write them well. Worse yet, each professor wants something a little different. Regardless of variations, however, the goal of lab reports remains the same: document your findings and communicate their significance. With that in mind, we can describe the report’s format and basic components. Knowing the pieces and purpose, you can adapt to the particular needs of a course or professor.


Typical Components:

  1. Title Page
  2. Abstract
  3. Methods and Materials
  4. Experimental Procedure
  5. Results
  6. Discussion
  7. Conclusion
  8. References
  9. Appendices


2. The Abstract: summarizes four essential aspects of the report: a) the purpose of the experiment (sometimes expressed as the purpose of the report) b) key findings, c) significance and d) major conclusions. The abstract often also includes a brief reference to theory or methodology. The information should clearly enable readers to decide whether they need to read your whole report. The abstract should be one paragraph of 100-200 words (the sample below is 191 words). (See also Components of Documents / Abstracts and Executive Summaries)

Sample Abstract


3. The Introduction: is more narrowly focused than the abstract. It states a) the objective of the experiment and b) provides the reader with background to the experiment. State the topic of your report clearly and concisely, in one or two sentences. When determining the objective, be sure to identify the end goal of the experiment itself, not the pedagogical goal of the experiment:

The objective of this experiment was to learn how to use the SEM.
(The Professor’s reason for having you do the lab, but not the objective of the lab itself).

The objective of the experiment was to determine the composition of an unknown sample using Scanning Electron Microscopy.
(This is your key result)



*Note on Verb Tense: Introductions often create difficulties for students who struggle with keeping verb tenses straight. These two points should help you navigate the introduction:


  • “The objective of the experiment was…”


  • “The purpose of this report is…”
  • “Bragg’s Law for diffraction is…”
  • “The scanning electron microscope produces micrographs …”

4. Methods and Materials (or Equipment): can usually be a simple list, but make sure it is accurate and complete. In some cases, you can simply direct the reader to a lab manual or standard procedure: “Equipment was set up as in CHE 276 manual.”

5. Experimental Procedure: describes the process in chronological order. Using clear paragraph structure, explain all steps in the order they actually happened, not as they were supposed to happen. If your professor says you can simply state that you followed the procedure in the manual, be sure you still document occasions when you did not follow that exactly (e.g. “At step 4 we performed four repetitions instead of three, and ignored the data from the second repetition”). If you’ve done it right, another researcher should be able to duplicate your experiment.

6. Results: are usually dominated by calculations, tables and figures; however, you still need to state all significant results explicitly in verbal form, for example:

Using the calculated lattice parameter gives, then, R = 0.1244 nm.

Graphics need to be clear, easily read, and well labeled (e.g. Figure 1: Input Frequency and Capacitor Value). An important strategy for making your results effective is to draw the reader’s attention to them with a sentence or two, so the reader has a focus when reading the graph.


7. The Discussion is the most important part of your report, because here, you show that you understand the experiment beyond the simple level of completing it. Explain. Analyse. Interpret. Some people like to think of this as the “subjective” part of the report. By that, they mean this is what is not readily observable. This part of the lab focuses on a question of understanding “What is the significance or meaning of the results?” To answer this question, use both aspects of discussion, a) Analysis and b) Interpretation.

a) Analysis: What do the results indicate clearly? What have you found? Explain what you know with certainty based on your results and draw conclusions:

Since none of the samples reacted to the Silver foil test, sulfide, if present at all, does not exceed a concentration of approximately 0.025 g/l. It is therefore unlikely that the water main pipe break was the result of sulfide-induced corrosion.

b) Interpretation: What is the significance of the results? What ambiguities exist? What questions might we raise? Find logical explanations for problems in the data:


More particularly, focus your discussion with strategies like these:

i) Compare expected results with those obtained: If there were differences, how can you account for them? Saying “human error” implies you’re incompetent. Be specific; for example, the instruments could not measure precisely, the sample was not pure or was contaminated, or calculated values did not take account of friction.


iii) Explain your results in terms of theoretical issues: Often undergraduate labs are intended to illustrate important physical laws, such as Kirchhoff’s voltage law, or the Müller-Lyer illusion. Usually you will have discussed these in the introduction. In this section move from the results to the theory. How well has the theory been illustrated?

iv) Relate results to your experimental objective(s): If you set out to identify an unknown metal by finding its lattice parameter and its atomic structure, you’d better know the metal and its attributes.

v) Compare your results to similar investigations: In some cases, it is legitimate to compare outcomes with classmates, not to change your answer, but to look for any anomalies between the groups and discuss those.

vi) Analyze the strengths and limitations of your experimental design: This is particularly useful if you designed the thing you’re testing (e.g. a circuit).

8. The Conclusion: can be very short in most undergraduate laboratories. Simply state what you know now for sure, as a result of the lab:

Example: The Debye-Sherrer method identified the sample material as nickel due to the measured crystal structure (fcc) and atomic radius (approximately 0.124 nm).


9. References: include your lab manual and any outside reading you have done. (See Online Handbook / Accurate Documentation for an appropriate way to reference in your field)

10. Appendices typically include such elements as raw data, calculations, graphs pictures or tables that have not been included in the report itself. Each kind of item should be contained in a separate appendix. Make sure you refer to each appendix at least once in your report. For example, the results section might begin by noting: “Micrographs printed from the Scanning Electron Microscope are contained in Appendix A.”

Useful Further Reading: Porush, D. A Short Guide to Writing About Science. Toronto: HarperCollins, 1995. Although this book uses the “scientific article” as the basic form for writing, it essentially views that as an extended lab report. Therefore, it has useful chapters on each of the sections of a lab report.

Our pages in the Online Handbook / Components of Documents section may also be useful.