How Science Works
Evidence, models, measurement, uncertainty, scientific language and evaluating claims.
What science is—and what it is not
Science is a way of building and testing explanations about the natural world using observation, measurement, models and evidence.
GuideHypothesis, theory and law: the differences
In science, a hypothesis, theory and law are different kinds of statements; a theory does not simply 'graduate' into a law.
GuideWhy science uses standard units
Standard units let measurements be communicated, compared and reproduced without ambiguity.
GuideAccuracy, precision and measurement uncertainty
A measurement can be repeatable without being close to the true value, and every real measurement has some uncertainty.
GuideWhy scientists use models
Models simplify reality so scientists can reason about systems that are too large, small, slow, fast or complicated to study directly in every detail.
GuideCorrelation and causation are not the same thing
Two things can change together without one causing the other.
GuidePeer review, replication and scientific confidence
Peer review checks whether research is suitable for publication, while replication and later evidence show whether a result is dependable.
GuideHow to evaluate a science claim
A strong science claim tells you what was measured, how it was measured, what comparison was made and how large the uncertainty is.