IA3 Research Investigation: Evidence, Claims and Evaluation
The research investigation asks you to answer a physics question using secondary sources, evaluate the evidence, and reach a justified conclusion. Unlike the experiment, you do not collect data; your skill is in selecting credible sources, synthesising their findings, and evaluating their limitations.
Concepts to command
- Research question: focused, answerable from literature, and physics-based, ideally with a measurable relationship.
- Sources: prefer peer-reviewed journals and authoritative bodies over blogs; record author, year and publication.
- Evidence quality: consider sample size, method, whether variables were controlled, and whether results were replicated.
- Synthesis: compare sources, note agreement and disagreement, and explain discrepancies with physics.
- Conclusion: answer the question directly, state confidence, and identify what further evidence would strengthen it.
Traps to watch
- Describing sources one by one without comparing them.
- Treating a single study as conclusive.
- Confusing correlation with causation in reported data.
- Making claims beyond what the cited evidence supports.
- Omitting limitations of the evidence base.
Worked example
Question: how does surface area affect drag on a falling object? Two sources may agree that drag rises with area but disagree on the exponent because of different shapes and speeds. The evaluation should note the differing Reynolds-number regimes and conclude that drag increases with area, with the exact relationship depending on flow regime. Stating that limitation shows evaluation, not weakness.
Rule of thumb
For every claim, ask: which source, how strong is its method, and does it agree with the others? A conclusion that names its confidence level and its limits scores highest.