The lab report is the most common writing assignment in undergraduate STEM. This guide covers every section — title, abstract, introduction, materials and methods, results, discussion, and conclusion — with subject-specific tips for chemistry, biology, physics, and engineering.
A lab report communicates what you did in the laboratory, what you observed, what it means, and how confident you are in your conclusions. It is the written equivalent of a peer-reviewed scientific paper — scaled for an undergraduate context. The key difference from a practical logbook (which records what you did) is that a lab report also interprets, evaluates, and contextualises the results against published science.
Lab reports serve two academic purposes: demonstrating that you carried out the practical correctly, and showing that you understand why the results turned out the way they did — including when things go wrong.
| Section | Content | Tense |
|---|---|---|
| Title | Specific, informative, concise | — |
| Abstract | One paragraph: aim, method, key result, conclusion | Past |
| Introduction | Background theory, aim, hypothesis | Present (theory) + Past (your aim) |
| Materials & Methods | Reproducible description of the procedure | Past passive |
| Results | Data, tables, figures, statistical analysis | Past |
| Discussion | Interpretation, comparison to theory, error analysis | Present/Past mixed |
| Conclusion | Summary of findings and their significance | Past/Present |
| References | All sources cited | — |
The title should tell the reader exactly what was measured and under what conditions. It does not need to be clever — it needs to be precise.
Written last, placed first. The abstract is a self-contained mini-report — 100–250 words depending on the course. It should cover:
Include a specific result. "Catalase activity peaked at 37°C, with a reaction rate of 0.84 mol/min, declining sharply above 55°C" is more useful than "results showed a trend." Markers look for numerical specificity in STEM abstracts.
The introduction provides the theoretical framework for the experiment. It explains the scientific principles behind what you are doing so that a reader who did not attend the lab session can understand why this experiment was designed the way it was. Structure it as:
The introduction is not a step-by-step description of the method — that goes in the Methods section. Do not start your introduction with "In this experiment I will…"
The methods section must be sufficiently detailed that someone else could replicate your experiment exactly. It is not a shopping list — write it as prose in the past tense, passive voice.
Do not copy the method from the lab manual word for word. The methods section must be written in your own words. Copying verbatim from a provided protocol is plagiarism and will be detected. Paraphrase and integrate into past-tense prose.
Our STEM specialists help with every section of lab reports — including data analysis, error discussion, and correctly formatted references.
The results section presents your data without interpretation. Show what you found, not what it means — that comes in the discussion.
The discussion is the most intellectually demanding section and typically carries the most marks. It asks you to think — not just report.
Students often write "human error" as a catch-all. This is not sufficient — you must identify specific sources of uncertainty:
The conclusion is short — typically one paragraph. It restates whether the hypothesis was supported or rejected, summarises the key finding, and briefly states the scientific significance. Do not introduce new data or begin a new argument. The conclusion should answer the research question posed in the introduction.
Conventions vary by institution and discipline. Physics and chemistry typically prefer passive voice and third person ("the solution was heated" rather than "I heated the solution"). Biology courses increasingly accept first person. Biology and some engineering courses often now accept "we" for group labs. Check your course guidelines — when in doubt, use past tense passive voice.
Discuss it honestly in the discussion section. Unexpected or contradictory results are not failures — they are scientifically interesting. Identify potential sources of error, consider whether the discrepancy is within the expected margin of experimental error, and discuss what might be done differently to improve agreement. Never adjust your data to match expected values.
Yes — any theory or published value cited in the introduction or discussion must be referenced. This includes the textbook definition of the enzyme you tested, the accepted value you are comparing your result to, and any method you adapted from a published protocol. Use the citation style required by your department.