How are scientific theories tested through experiments?

In the principles of physical science, scientific theories are tested through a rigorous process of experimentation and observation that serves to evaluate their validity and predictive power. This process is central to the scientific method, which functions as a cycle of hypothesis development, testing, and refinement.12

The Testing Process

• Hypothesis Formulation: Researchers begin by developing a hypothesis—a tentative, testable assumption—based on existing knowledge.12
• Experimental Design: To test a hypothesis, scientists gather empirical evidence through controlled experiments. A key component is the use of a control group, which provides a standard for comparison to ensure that observed effects are due to the treatment rather than external variables.34
• Evaluation and Modification: If experimental outcomes are inconsistent with the hypothesis, the hypothesis is modified and retested. Theories are developed from the broad general explanations that emerge once these hypotheses have been consistently supported by data.2
• Falsifiability: According to the criterion of falsifiability, a theory is considered scientific only if it is possible to conceive of an experiment that could prove it false. Theories are never considered infallible; rather, they are incrementally corroborated by the repeated absence of disconfirming evidence.51