Overview
This lecture reviews how to write hypothesis statements in scientific experiments, focusing on the roles of independent and dependent variables.
What Is a Hypothesis Statement?
- A hypothesis statement is a key part of the scientific method.
- It provides a testable prediction about what will happen in an experiment.
- It is usually written in an "If...then..." format.
Structure of Hypothesis Statements
- The "if" part states the independent variable (what you change).
- The "then" part states the dependent variable (what you observe or measure).
- Hypotheses must be testable through experiment or observation.
Examples
- Elephant toothpaste example: "If we reduce the size of the bottle, then the elephant toothpaste will go higher."
- Independent variable: size of the bottle.
- Dependent variable: height of the elephant toothpaste.
- Pickle juice and cramps example: "If we take pickle juice, then we will get fewer cramps."
- Independent variable: dose of pickle juice.
- Dependent variable: frequency of cramps.
Identifying Variables
- Independent variable: the factor you change on purpose during the experiment.
- Dependent variable: what changes as a result and is measured.
Key Terms & Definitions
- Hypothesis Statement — a testable prediction stated as an "if...then..." sentence for scientific experiments.
- Independent Variable — the variable that is intentionally changed by the experimenter.
- Dependent Variable — the variable that is measured or observed to change in response to modifications of the independent variable.
Action Items / Next Steps
- Practice writing hypothesis statements with provided examples during the next class session.