How to Write a Lab Report

Each laboratory report should have four parts: an Introduction, the Procedure, a Summary of Results and Data, and a Discussion. If any of these sections is missing, the Lab Report is considered incomplete, and will not be accepted. Make sure to title each section so that it is obvious what it is. A reader should not have to guess whether he is reading your Introduction or your Procedure section, for example.

          In the Introduction, you should outline what was done in the lab (e.g. "We were to determine the density of several different objects...") and state your hypothesis (e.g. "We thought that the pennies would be the most dense, the marbles would be the least dense..."). The goal of the Introduction is to make sure that anyone reading the report would be able to get a general idea of what you were doing in lab, and what your original hypothesis was.

          In the Procedure, you should describe the specifics of what you did in lab, and how you did it. Try, as always, to be brief and succinct, but provide enough detail that anyone reading the report could reproduce your results using your description. The goal of the Procedure section is to communicate your lab technique for the benefit of your reader.

          In the Summary of Results and Data, you should report your data (may be presented verbally, or in table form, whichever is most appropriate). The goal of the Summary of Results and Data section is to make sure the reader knows the measurements and calculations you made.

          In the Discussion, you should evaluate your hypothesis based upon your data. If you proved your hypothesis, you should say so and explain how your data show this. If your data disproved your hypothesis, you should also say so, and similarly show how your data show this. If you had an unexpected result, you should point this out. You should definitely discuss what you learned from the lab. You should also discuss sources of error. For example, if it was difficult to read the graduated cylinder, and you think this seriously affected your results, say so. (This is just a suggestion--please don't everyone use this exact example. Do your own thinking, please. If you need other suggestions, talk to me.)

The most important thing to keep in mind when doing a lab report is your personal and professional integrity. Do not change your original hypothesis just because it ended up being wrong: some of the best scientists write papers in which they disprove their original hypothesis. It is the results that matter, not your prediction, so be prepared to humbly admit mistakes and missteps, since being wrong is also from time-to-time part of the scientific method. You learn more from being wrong than being right, most of the time.