How to Write a Lab Report (For High School Science)
A lab report follows a predictable format. Once you learn it, you can knock them out in 60-90 minutes. Here’s the standard structure plus what teachers actually weight when grading.
Quick answer
Standard lab report has 6 sections: Title, Abstract, Introduction, Methods, Results, Discussion. Some teachers add Conclusion and References. Most points come from Results (data + analysis) and Discussion (interpretation).
The 6 sections
1. Title
Specific and informative. NOT “Lab 4.” YES “The Effect of Temperature on Enzyme Reaction Rate in Catalase.”
2. Abstract (50-150 words)
One paragraph summarizing the whole report. Question, method, result, what it means. Write this LAST, after everything else is done.
3. Introduction
- Background: what’s already known about the topic
- Hypothesis: what you predicted and why
- Purpose: what your experiment will test
4. Methods
Step-by-step description of what you did. Past tense, third person. Detailed enough that someone could reproduce your experiment. Include materials list.
5. Results
Your actual data, organized in tables or graphs. NO interpretation here — just data. Caption every table and figure (Figure 1, Table 1).
6. Discussion
This is where the points are. What did your data show? Did it match your hypothesis? Why or why not? What were the sources of error? What would you do differently?
Optional: Conclusion + References
Conclusion is a short summary of findings. References cite any sources you used (textbook, websites).
Common mistakes
- Writing the abstract first (write it last).
- Putting interpretation in the Results section (interpretation goes in Discussion).
- Vague methods (“we measured the rate” — measured how? With what?).
- Skipping discussion of error sources.
- Not labeling axes on graphs.
If your data doesn’t match your hypothesis
That’s fine. It’s not a failure — it’s data. In the Discussion, explain what you observed, suggest reasons, and discuss what would let you test alternatives. Honest “the data didn’t match my hypothesis, possibly because…” earns full credit.
Tools that help
- Google Sheets or Excel — for tables and basic charts
- Desmos — for plotting data with trend lines
- Grammarly — for proofreading the writing