How to Write a Hypothesis for a Lab Report

Experiments rely on testable hypotheses.

The hypothesis is often thought of as the most difficult part of the scientific method. The hypothesis represents the subject around which the entire experiment revolves. You can follow a few simple steps to generate a hypothesis that is testable and explains how variables are connected.

Instructions

1. Develop your research problem. Think about two events, objects, or subjects and see how they may be related.

2. Come up with a general hypothesis, which is created after you have observed something. For example, if you notice during a research period that acid rain affects the population of fish in a lake, your general hypothesis could be "Acid rain reduces fish population."

3. Make your general hypothesis more specific. For example, you could say "If acid rain in a lake is related to fish population, then lower pH levels caused by acid rain lead to a decline in fish population." You could also say "As pH levels are lowered by acid rain, the rate of population decline of fish in the water increases."

4. Identify your variables. In the statements in Step 3, you have an independent variable (acid rain and pH levels) and the dependent variable (fish population).

5. Re-read your hypothesis and ensure it is a testable statement. If you cannot build an experiment around the hypothesis, rewrite it so that you can test the variables.

References

• University of North Carolina: Scientific Reports
• Experiment Resources: How to Write a Hypothesis
• Access Excellence: Writing Hypotheses