The scientific method is the systematic approach to acquiring reliable knowledge through observation, hypothesis, and experiment.
Steps
- Observe a phenomenon and formulate a question.
- Propose a hypothesis — a testable prediction.
- Design an experiment with controlled variables.
- Collect and analyse data.
- Draw conclusions and compare with the hypothesis.
Variable types
| Type | Definition | Example |
|---|---|---|
| Independent | Variable you change | Applied voltage |
| Dependent | Variable you measure | Current through resistor |
| Controlled | Variables held constant | Temperature, wire length |
Reproducibility — An experiment must be repeatable (same lab) and reproducible (different lab). Without this, results are not reliable.
Null hypothesis — Assume no effect exists (). The experiment tries to reject with statistical confidence.
Key insight: A good experiment doesn't prove a hypothesis — it fails to disprove it. One contradicting observation can overturn a theory, but no number of confirming observations can prove it absolutely.
Common pitfall: An experiment that cannot fail is not an experiment. If no conceivable data would count against the hypothesis, the procedure tests nothing — build in the possibility of being wrong.