A scientific procedure undertaken to test a hypothesis or discover an unknown effect.An experiment is a controlled procedure designed to test a hypothesis, measure a phenomenon, or discover an unknown effect. In physics, experiments are the ultimate arbiter of theory — they confirm predictions, challenge established models, and reveal new phenomena that drive theoretical advances. From Galileo's inclined plane to modern particle colliders, experiments have shaped our understanding of the universe by providing empirical evidence that separates fact from speculation.
The modern experimental method was formalized by Francis Bacon in the 17th century and exemplified by Galileo Galilei, who combined systematic observation with mathematical analysis. Since then, experiments have evolved from simple benchtop setups to massive international collaborations like CERN's Large Hadron Collider.
A well-designed experiment isolates variables, controls conditions, and measures outcomes with precision. It typically involves a hypothesis, a setup that manipulates one or more parameters, and a measurement system that records the results. The data are then analyzed statistically to determine whether the observed effect is real or due to chance, and the results are compared with theoretical predictions to validate or refute the model.
Experiments are the foundation of all applied physics, from testing new materials for batteries to validating the safety of nuclear reactors and developing medical imaging technologies.
The most expensive experiment in history is the Large Hadron Collider, costing about $4.75 billion, which discovered the Higgs boson in 2012 — a particle predicted 48 years earlier.


