Purpose
What does a lab report introduction do?
The introduction gives readers the scientific context needed to understand the investigation. It explains the relevant principles, identifies the problem, and states what the experiment was designed to determine.
A strong introduction moves from general scientific background to the specific research question. It should not repeat the complete procedure.
Recommended structure
Five parts of a strong introduction
- Introduce the scientific topic.
- Explain relevant scientific principles.
- State the investigation objective.
- Identify the research question and variables.
- Present a testable hypothesis.
Scientific background
Include only relevant scientific theory
Define important concepts, relationships, equations, or mechanisms that directly support the investigation. Remove information that does not help the reader understand the experiment.
- Define the main scientific concept.
- Explain how the variables are related.
- Include relevant equations when necessary.
- Cite scientific information from other sources.
Objective
State what the investigation will determine
Objective exampleTo determine how solution temperature affects the rate of a chemical reaction.
Research question
Write a focused and measurable question
The question should identify the experimental system, the independent variable, and the dependent variable.
Example questionHow does solution temperature affect reaction time?
Variables
Identify what changes and what is measured
Independent variable
What is deliberately changed
The factor selected and controlled by the investigator.
Dependent variable
What is measured
The response recorded during the investigation.
Hypothesis
Make a testable scientific prediction
Hypothesis structureIf [independent variable changes], then [dependent variable will change], because [scientific reason].
The hypothesis does not need to be correct. It must be specific enough to evaluate using experimental evidence.
Common mistakes
Introduction problems to avoid
- Including unrelated scientific theory.
- Repeating the full procedure.
- Leaving the objective unclear.
- Writing a hypothesis that cannot be tested.
- Confusing independent and dependent variables.
- Using scientific claims without citations.
Related guides
Continue building the report
Review the complete section order in the Lab Report Format guide, or follow the complete workflow in How to Write a Lab Report.
Questions and answers
Lab report introduction FAQ
What should a lab report introduction include?
It should include relevant scientific background, the investigation objective, research question, variables, and a testable hypothesis when required.
How long should a lab report introduction be?
It should be long enough to explain the necessary scientific context without including unrelated theory or detailed procedural steps.
Should the procedure appear in the introduction?
Only a brief overview may be included. Detailed equipment and procedural steps belong in the materials and methods section.
Where should the hypothesis appear?
The hypothesis normally appears near the end of the introduction after the scientific background and research question.