TEAS® Science Study Guide
Hypotheses, Theories & Laws
These three words mean very different things in science, and the TEAS tests whether you know the difference.
- Hypothesis — A single testable prediction, often phrased as "if… then…" ("If plants get more sunlight, then they will grow taller"). It’s the starting point, not a proven fact.
- Theory — A broad, well-supported explanation backed by a large body of evidence gathered over time. A theory is not a guess. The theory of evolution and cell theory are examples — well-established, not uncertain.
- Law — A statement, often mathematical, that describes what consistently happens in nature but doesn’t explain why. The law of conservation of mass is an example.
The distinction TEAS loves: a theory explains why something happens; a law describes what happens. And in everyday speech "theory" means a hunch — but in science it means the opposite: a heavily supported explanation.
Terms to know
- Hypothesis — A testable "if… then…" prediction.
- Theory — A well-supported explanation backed by extensive evidence.
- Law — A description of a consistent natural pattern, often mathematical.
What the TEAS asks most
- Is a scientific theory just a guess? No — it’s backed by extensive evidence.
- What’s the difference between a law and a theory? A law describes what happens; a theory explains why.
- How is a hypothesis usually phrased? As an "if… then…" statement.