AI Tutor
In everyday speech, people often say, "It's just a theory," meaning an educated guess or a hunch.
In science, that definition is completely backwards — so how do scientists actually tell hypotheses, laws, and theories apart?

Hypotheses, Laws, and Theories

A hypothesis is a proposed, testable explanation for a specific observation that can be supported or rejected through experimentation.
A scientific law describes an observed pattern or relationship in nature under specific conditions, often expressed as a mathematical formula, telling us what happens without explaining why.
A scientific theory is an in-depth, evidence-backed explanation of why and how natural phenomena occur, tying together hundreds of tested hypotheses and observations.
If a hypothesis gathers enough evidence over time, does it eventually "level up" and become a law?

The Hierarchy Fallacy

A common misconception is that scientific ideas follow a ladder: a hypothesis graduates into a theory, and a theory eventually graduates into a law.
In reality, theories and laws do completely different jobs — a law states what physical relationships exist, while a theory explains the mechanism driving them.
In 1789, Antoine Lavoisier formulated the Law of Conservation of Mass after carefully weighing reactants and products, establishing that mass never changes in a closed reaction.