Introduction

Many people might use hypothesis, model, theory, and law without considering their fundamental differences. However, in scientific research each has its own specific meaning, and it is important to understand these.

Hypothesis

A hypothesis is based on observations, and therefore a relation you see between cause and effect. By performing more experiments an hypothesis can be supported or proven to be false, but it is never possible to prove it to be generally correct. Example: Taylor’s Hypothesis.

Model

A (conceptual or physical) model is used to explain complex phenomena. It is a simplification of reality, but it includes all important aspects in order to be able to predict observations. Example: Standard Model.

Theory

A (scientific) theory is a hypothesis that has been supported by repeated testing. As long as it is not disproven by hard evidence, a theory remains valid. As such, it can be considered a generally accepted hypothesis. A theory explains the underlying physics. Example: Einstein’s Theory of Relativity.

Law

A (scientific) law is an mathematical relation that describes a range of observations (without exceptions). Where a theory explains, a law only desribes (it does not answer why?). Many laws are only valid under limited circumstances, which is why forming new laws is hard nowadays. Example: Newton’s Laws of Motion.

All science is based on empirical observations (facts), which are being analysed to gain understanding of physical processes. There is no absolute truth, as anything can (and will be) be overturned if proven false. However, note that also the definition of proof varies between scientific disciplines. Most importantly, be aware that these differences between definitions exist (and can not be interchanged with each other), and be as accurately as possible within your own discipline.

Famous scientific theories that were disproven later: Luminiferous aether.