Scientific Method, Environment and Science Policy
Core concepts
Know the steps of the scientific method: observation, hypothesis, controlled experiment, data collection, analysis, and conclusion. Understand variables (independent, dependent, controlled), reliability versus validity, and the role of peer review. In environment and policy, understand pollution types, climate change causes and mitigation, biodiversity loss, sustainable development, and how scientific evidence informs regulation and public policy.
Common traps
- Confusing correlation with causation.
- Mixing reliability (repeatability) with validity (measuring what you intend to measure).
- Assuming a hypothesis is proven rather than supported or rejected.
- Confusing weather (short-term) with climate (long-term patterns).
- Ignoring that policy decisions involve economic and social factors, not evidence alone.
Worked example and rule of thumb
Rule of thumb: for any experiment, identify the independent variable (what you change), the dependent variable (what you measure), and at least two controlled variables (what you keep constant). Example: testing whether fertiliser affects plant growth, the fertiliser amount is independent, plant height is dependent, and light, water, and soil type are controlled. For policy questions, structure answers as: evidence, stakeholder impact, and trade-offs. This demonstrates balanced scientific reasoning and earns marks for evaluation.