Students are asked to write lab reports for two main reasons:
- To share what they have learned from performing an experiment and evaluating the results
- To demonstrate that they understand the scientific method.
A lab report is well done if a student can effectively describe the processes they completed and the results they obtained and if they can show that they comprehend the greater principles behind those processes and results.
Writing Objectively
In science writing, objectivity is of utmost importance. Facts and logic are essential, and subjective bias should be avoided. Use the following pointers to accomplish this goal.
- Utilize the passive voice. The passive voice is used in formal scientific writing, particularly in descriptions of research conducted, because it draws attention to the action of the sentence, not the one who performs the action. (The passive voice is not as common in conclusions, for example.)
Example: “Bacterial samples were collected and weighed.”
- Acknowledge mistakes and failures. In scientific research, it is crucial to be honest about what occurred during an experiment. Maintaining a degree of transparency is paramount because scientists incorporate others’ findings into their own research, and a falsified conclusion may have disastrous results. Furthermore, a negative result may prove just as useful as a positive result because it eliminates unproductive avenues for future research.
Writing Precisely
- Lab reports are factual. Eliminate figurative language. The purpose of a lab report is to present the experiment’s methodology and results precisely. The creativity lies in the design of the experiment and the interpretation of the results, not the language of the report.
- Do not include extraneous detail. Details should be limited to the process, instrumentation, background, and results of an experiment; do not load the report down with details unrelated to the experiment. Scientific communication is often space-limited, so let readers know what they need to know as concisely as possible.
Writing with Clarity
- Use simple language. Wherever possible, use the “boring” word that gets the point across rather than a “flowery” word that may confuse or distract the reader.
- Do not worry about word repetition. Using the same word over and over increases clarity.
- Use simple sentence structures. Make sure the subject and the action of the sentence are close together.
- Use tenses correctly. Use the past tense to describe methods and procedures and to refer to other studies that took place in the past, but use the present tense when referring to the findings presented in the current lab report.
The General Structure of a Lab Report
This handout is a general guide to negotiating scientific structure, but the specific style and order of a lab report vary from discipline to discipline.
Abstract
See the University Writing Center handout on Abstracts.
An abstract is a brief, one- or two-paragraph summary of the lab report’s contents. A reader should understand the objectives of the research, how the study was conducted, what the results show, and the significance of the findings.
Because the abstract is a summary of the contents, it is written last, although it will appear before the body of the report. When others are looking for sources for their own research, they can read the abstract to see if the full lab report is useful, so it has to be both complete and condensed.
Qualities of an Effective Abstract
- It relates the work to the field. How does the applied research fit with comparable work? What does the reader need to know that isn’t common knowledge in the field?
- It is concise. An effective abstract should be one or two unified, coherent paragraphs that are independent of the rest of the paper.
- It presents the experiment chronologically. The abstract should present the experiment in the order that it was conducted.
- It adds no information that is not in the report. The abstract should stay within the bounds of the experiment.
- It is intelligible to a wide audience. The abstract should be the least technical part of the entire document. Abstracts are designed to entice the reader or at least give them a basic idea of what was accomplished.
Introduction
The introduction is a way for the writer to move from general to specific information. This section should narrow the scope of the research to a particular topic. Limit the introduction to research that relates to the experiment, and guide the reader through this information to the project’s objective. The last sentence should be a definitive statement of this objective and the hypothesis developed before the study was conducted.
Qualities of an Effective Introduction
- It establishes a context for the work. The introduction should provide important primary research literature, with citations, and detail what this research contributed to contemporary understanding of the topic.
- It explains the rationale behind the experiment. Why is there a need for this experiment to be done? What information is missing from the existing body of research?
- It clearly states an objective and a hypothesis. The reader needs to know the purpose of the experiment and the expected results.
Methods
The methods section is a step-by-step guide to the experiment. This section should be written so another scientist could replicate the experiment exactly and without confusion.
Qualities of an Effective Methods Section
- It does not include any calculations. Save manipulation of data for the results section. Remember that the methods section does not disclose the results.
- It glosses over common procedures. Don’t spend half a page talking about how to use a ruler. The reader just needs to know that something was measured.
- It does not quote or cite a lab manual.
Results
The results section presents the reader with an explanation of the findings through text, tables, and figures. It should include a very brief summary of any methods that give context to the results. Raw data is not presented here.
Qualities of an Effective Results Section
- It points out trends in the data. The results section displays analytical skills and prepares readers for the discussion section.
- It does not present the same data in both a table and a figure. Choose the most effective and understandable form that conveys the results concisely.
Example of a Figure
Example of a Table
Table 1. Data for the Time and Associated Voltage.
| T +/- 0.02 s | V (mm) | δV (mm) | Vo (mm) | V/Vo | δ(V/Vo) | ln(V/Vo) | δln(V/Vo) |
|---|
| 0.00 | 195 | 2 | 195 | 1.00 | 0.02 | 0.00 | 0.02 |
| 0.10 | 182 | 1 | 195 | 0.93 | 0.01 | 0.07 | 0.02 |
| 0.20 | 167 | 1 | 195 | 0.86 | 0.01 | 0.16 | 0.01 |
| 0.30 | 153 | 2 | 195 | 0.78 | 0.02 | 0.24 | 0.02 |
| 0.40 | 140 | 1 | 195 | 0.72 | 0.01 | 0.33 | 0.01 |
Discussion
The discussion section is where the experimenter determines whether the data obtained supports the hypothesis. This section draws conclusions from the results, explains what the results mean, and, if they differ from other findings, examines why this occurred.
Qualities of an Effective Discussion Section
- It relates the topic back to the objectives. Connect what was found to the questions raised in the introduction.
- It limits conclusions to what the data can support. Resist the temptation to make overarching claims about the implications of the findings.
- It notes problems with methods and explains anomalies in the data. If necessary, provide thoughtful commentary on how possible errors in the process or instrumentation may have affected the conclusion.
References
This section provides a list of the sources cited in the lab report.
Because the sciences and engineering disciplines do not follow one citation format, check with the instructor or refer to the syllabus to determine the preferred citation style. For specific instructions, the AppState Library Guide for Chemistry provides links to two formatting and documentation styles: ACS and CSE.