How to Write a Lab Report (Format, Template & Example)
A lab report is a structured scientific document that records what you did in an experiment, what you found, and what those findings mean. It follows a standard format used in high school, college, and research settings: Title, Abstract, Introduction, Methods, Results, Discussion, and Conclusion. This guide explains how to write a lab report section by section, with a format overview, a template, and a complete example.
For the section that also appears in academic papers and research submissions, see our guide on how to write an abstract.
Lab report format
A standard lab report format includes the following sections in order:
| Section | Purpose | Approx. length |
|---|---|---|
| Title | Names the experiment clearly | One line |
| Abstract | Summarizes the whole report | 100–200 words |
| Introduction | Background, purpose, and hypothesis | 200–400 words |
| Methods | What you did and how | 200–400 words |
| Results | What you observed and measured | Variable — data + narrative |
| Discussion | What the results mean | 300–600 words |
| Conclusion | Summary of findings and their significance | 100–200 words |
| References | Citations for sources used | As needed |
In shorter or introductory-level reports, some instructors combine Discussion and Conclusion into one section. Always follow your specific assignment guidelines.
How to write a lab report
Title
A good lab report title describes the experiment specifically: what was tested, what was measured, and under what conditions.
Weak: “Enzyme Lab”
Strong: “The Effect of Temperature on the Rate of Enzyme Activity in Catalase”
The title should be a noun phrase, not a question or a sentence. Avoid abbreviations.
Abstract
The abstract is a self-contained summary of the entire report, written after the rest of the report is complete. It covers:
- The purpose of the experiment
- The method used (briefly)
- The main results (including key numbers)
- The conclusion
This experiment investigated the effect of temperature on the activity of the enzyme catalase in hydrogen peroxide decomposition. Potato discs were exposed to hydrogen peroxide at four temperatures (4°C, 20°C, 37°C, and 55°C), and the rate of oxygen production was measured using a water displacement method. Results showed that enzyme activity peaked at 37°C, producing an average of 4.8 mL of oxygen per minute. Activity was significantly reduced at 4°C and 55°C, suggesting denaturation at high temperatures. These findings support the hypothesis that catalase activity is temperature-dependent and optimized near human body temperature.
Write the abstract last. Every sentence should carry specific information — no vague phrases like “interesting results were found.”
Introduction
The introduction provides background on the topic, states the purpose of the experiment, and presents the hypothesis. It answers:
- What is the scientific concept being tested? (background)
- Why is this experiment being conducted? (purpose)
- What do you predict will happen, and why? (hypothesis)
A hypothesis is a testable, falsifiable prediction in “if-then” form:
If temperature affects enzyme activity, then catalase will produce oxygen most rapidly at 37°C (human body temperature) and less rapidly at temperatures that are significantly higher or lower.
The introduction is not a history of the entire topic — keep it focused on what directly relates to the experiment.
Methods
The methods section (also called Materials and Methods or Procedure) describes exactly what you did, in enough detail that someone else could replicate the experiment. Write in past tense, third person, passive voice:
Potato discs (10 mm diameter, 3 mm thick) were cut using a cork borer and placed in 10 mL of hydrogen peroxide solution (3% concentration) at each of four temperatures: 4°C (ice bath), 20°C (room temperature), 37°C (water bath), and 55°C (water bath). Oxygen production was measured by collecting displaced water in an inverted graduated cylinder over a five-minute period. Each temperature condition was replicated three times.
Do not explain why you did each step in the methods — save interpretation for the discussion. List materials separately if required by your instructor.
Results
The results section presents what you observed and measured — without interpretation. Include:
- A written narrative describing the key findings
- Data tables with clearly labeled columns and units
- Graphs or figures (with captions) that make patterns visible
Results narrative:
Enzyme activity varied significantly with temperature (see Figure 1). At 4°C, an average of 1.1 mL of oxygen was produced per minute. At 20°C, production increased to 2.9 mL per minute. Activity peaked at 37°C with an average of 4.8 mL per minute. At 55°C, production dropped to 0.4 mL per minute.
Do not include “the data show that temperature affected the enzyme” in the results — that interpretation belongs in the discussion. The results section reports; the discussion interprets.
Sample data table:
| Temperature (°C) | Trial 1 (mL/min) | Trial 2 (mL/min) | Trial 3 (mL/min) | Mean (mL/min) |
|---|---|---|---|---|
| 4 | 1.0 | 1.2 | 1.1 | 1.1 |
| 20 | 2.8 | 3.0 | 2.9 | 2.9 |
| 37 | 4.7 | 5.0 | 4.8 | 4.8 |
| 55 | 0.3 | 0.4 | 0.5 | 0.4 |
Discussion
The discussion interprets the results: what do they mean, why did they happen, and how do they relate to existing knowledge? Structure it around three questions:
Did your results support the hypothesis?
The results supported the hypothesis. Catalase activity was highest at 37°C, consistent with the enzyme’s optimization for human body temperature. Activity declined at both 4°C and 55°C.
Why did this happen? (Explain the science)
At 4°C, molecular kinetic energy is reduced, decreasing the frequency of enzyme-substrate collisions and slowing the reaction rate. At 55°C, the high temperature disrupted the non-covalent bonds maintaining the enzyme’s three-dimensional structure, causing denaturation and loss of active site function.
What are the limitations and sources of error?
One limitation was the manual measurement of displaced water, which introduced human error and may explain the variation between trials. Future experiments should use a gas sensor for more precise measurement.
The discussion should also note whether your findings are consistent with published research on the topic — cite sources.
Conclusion
The conclusion is short: one to three sentences summarizing the experiment’s main finding and its significance.
This experiment demonstrated that catalase activity is temperature-dependent, with optimal function at 37°C. The sharp decline in activity at 55°C supports the principle of enzyme denaturation at high temperatures. These findings are consistent with the role of temperature as a regulator of enzyme-catalyzed reactions in biological systems.
Do not introduce new information or speculation in the conclusion. It is a summary, not an extension of the discussion.
References
Cite any sources used for background information in the introduction or to support interpretation in the discussion. Your instructor will specify the citation format (APA, MLA, or a discipline-specific style). A standard APA journal article citation looks like:
Berg, J. M., Tymoczko, J. L., & Stryer, L. (2015). Biochemistry (8th ed.). W. H. Freeman.
List all references alphabetically by author’s last name.
Lab report template
Title: [Specific, descriptive title of the experiment]
Abstract [Purpose — one sentence. Method — one or two sentences. Key results — two to three sentences with numbers. Conclusion — one sentence.]
Introduction [Background on the concept being tested — two to three paragraphs.] [Purpose of the experiment — one to two sentences.] [Hypothesis — if-then statement.]
Methods [Materials list (if required).] [Procedure — past tense, third person, passive voice. Enough detail to replicate the experiment.]
Results [Narrative description of key findings.] [Data table(s) with labeled columns and units.] [Figure(s) with captions, if applicable.]
Discussion [Did results support the hypothesis? Why or why not?] [Scientific explanation of the results.] [Limitations and sources of error.] [Comparison to published research, if applicable.]
Conclusion [One to three sentences summarizing findings and significance.]
References [Citations in the required format.]
Common mistakes to avoid
- Writing in first person in Methods — use third person passive: “The solution was heated,” not “I heated the solution.”
- Interpreting results in the Results section — report what you observed; save the “why” for the discussion.
- Vague hypothesis — “temperature will affect the enzyme” is not a hypothesis. State direction and include a reason.
- Omitting units — every measurement in a table or graph needs units (mL, °C, seconds).
- Writing the abstract first — write it last. The abstract summarizes a completed report.
- No error discussion — every experiment has sources of error. Acknowledging them is part of good scientific writing.
Use AI to compress your results narrative
Lab reports often include more data than prose can efficiently communicate. Paste your results and discussion sections into our free AI text summarizer to get a compressed read-back of the key findings — useful for checking whether your main conclusions are clearly stated before you submit.
Frequently asked questions
What is a lab report? A lab report is a structured document that records a scientific experiment: what was done, what was found, and what the findings mean. It follows a standard format — Title, Abstract, Introduction, Methods, Results, Discussion, Conclusion — used across high school and university science courses.
How long should a lab report be? Length depends on the assignment. A basic high school lab report is typically 500–1,000 words plus data tables. A university-level lab report is usually 1,500–3,000 words. Always check your instructor’s guidelines.
What is the difference between Results and Discussion in a lab report? Results presents the data — what you observed and measured, with tables and figures. Discussion interprets the data — what the results mean, why they happened, how they relate to the hypothesis, and what the limitations were.
Do you write a lab report in first or third person? Most scientific writing uses third person passive voice: “The solution was heated to 37°C” rather than “I heated the solution.” Some instructors allow first person — check your assignment guidelines.
How do you write a lab report abstract? Write it last. Include the purpose, method (brief), key results (with numbers), and conclusion in 100–200 words. Every sentence should carry specific information — avoid vague phrases like “interesting results were observed.”