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.
A good lab report does more than present data; it demonstrates the writer’s comprehension of the concepts behind the data. Merely recording the expected and observed results is not sufficient; you should also identify how and why differences occurred, explain how they affected your experiment, and show your understanding of the principles the experiment was designed to examine. Bear in mind that a format, however helpful, cannot replace clear thinking and organized writing. You still need to organize your ideas carefully and express them coherently.
1. The Title Page needs to contain the name of the experiment, the names of lab partners, and the date. Titles should be straightforward, informative, and less than ten words (i.e. Not “Lab #4” but “Lab #4: Sample Analysis using the Debye-Sherrer Method”). 2. The Abstract summarizes four essential aspects of the report: the purpose of the experiment (sometimes expressed as the purpose of the report), key findings, significance and 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).
Sample Abstract
This experiment examined the effect of line orientation and arrowhead angle on a subject’s ability to perceive line length, thereby testing the Müller-Lyer illusion. The Müller-Lyer illusion is the classic visual illustration of the effect of the surrounding on the perceived length of a line. The test was to determine the point of subjective equality by having subjects adjust line segments to equal the length of a standard line. Twenty-three subjects were tested in a repeated measures design with four different arrowhead angles and four line orientations. Each condition was tested in six randomized trials. The lines to be adjusted were tipped with outward pointing arrows of varying degrees of pointedness, whereas the standard lines had inward pointing arrows of the same degree. Results showed that line lengths were overestimated in all cases. The size of error increased with decreasing arrowhead angles. For line orientation, overestimation was greatest when the lines were horizontal. This last is contrary to our expectations. Further, the two factors functioned independently in their effects on subjects’ point of subjective equality. These results have important implications for human factors design applications such as graphical display interfaces.
3. The introduction is more narrowly focussed than the abstract. It states the objective of the experiment and provides the reader with background to the experiment. State the topic of your report clearly and concisely, in one or two sentences:
A good introduction also provides whatever background theory, previous research, or formulas the reader needs to know. Usually, an instructor does not want you to repeat the lab manual, but to show your own comprehension of the problem. For example, the introduction that followed the example above might describe the Debye-Sherrer method, and explain that from the diffraction angles the crystal structure can be found by applying Bragg’s law. If the amount of introductory material seems to be a lot, consider adding subheadings such as: Theoretical Principles or Background.
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 experiment is already finished. Use the past tense when talking about the experiment.
“The objective of the experiment was…”
The report, the theory and permanent equipment still exist; therefore, these get the present tense:
“The purpose of this report is…”
“Bragg’s Law for diffraction is …”
“The scanning electron microscope produces micrographs …”
Explanation:
