Elements of Scientific Method

1. Observations and measurements (quantitative data).
2. Hypothesis. A possible explanation for the observations—in other words, a tentative answer or an educated guess.
3. Experiments. The testing of a hypothesis under controlled conditions to see whether the test results confirm the hypothetical assumptions, can be duplicated, and are consistent. If not, more observations and measurements may be needed.
4. Theory. If a hypothesis passes enough experimental tests and generates new predictions that also prove correct, it takes on the status of a theory, a well-tested explanation of observed natural phenomena. (Even theories may be debated by scientists until experimental evidence decides the debate. If a theory does not withstand continued experimentation, then it must be modified, rejected, or replaced by a new theory.)
5.  Law. If a theory has withstood the test of many well-designed, valid experiments and there is great regularity in the results, that theory may be accepted by scientists as a law. This is a concise statement in words or mathematical equations that describes a fundamental relationship of nature. Scientific laws are somewhat analogous to legal laws, which may be repealed or modified if inconsistencies are later discovered. Unlike legal laws, however, scientific laws are meant not to regulate but to describe.