When reading research articles, you will likely come across the terms HYPOTHESIS, THEORY, and LAW. These words have specific meanings in science. The scientific method of research includes formulating hypotheses and testing them to see if they hold up to the realities of the natural world. Successfully verified hypotheses can lead to either theories or laws.
A hypothesis is a tentative assumption or explanation made before any research that can be verified by further investigation. It is made so that it can be verified to see if it might be true or false.
In order to put a hypothesis into a proven theory, researchers design experiments to challenge their ideas under the conditions of the natural world. By adhering to the scientific method and working carefully, scientists can finally accumulate enough evidence to prove their hypothesis, thus making it a theory with predictive and extrapolative power. A scientific theory is a description of the nature that scientists have verified through rigorous testing. A theory explains how nature behaves under specific conditions. Theories tend to be as broad as their supporting scientific evidence will permit. A theory is a well-supported explanation of some aspect of the natural world based on observations.
Some examples of famous scientific theories that have shaped our understanding of the natural world include:
A law is a statement that summarizes an observed regularity or pattern in nature and gives the relationship between variables. Like theories, laws describe phenomena that scientists have found to be provably true. Laws develop from discoveries and rigorously tested hypotheses, and new theories generally uphold and expand laws.
Examples of some famous laws include:
Both scientific laws and theories are considered as facts. However, theories and laws can be disproven when new evidence appears. For example, certain accepted truths of Newtonian physics were partially disproven by Albert Einstein's theory of relativity. The work of Louis Pasteur disproved prior theories of disease in animals. If thorough scientific research upends a previously held belief, scientists must find new hypotheses that better describe how nature works.
Scientific laws differ from theories in that laws tend to describe a narrower set of conditions. A scientific law might explain the relationship between two specific forces or between two changing substances in a chemical reaction. Theories are normally more expansive and they focus on the how and why of natural phenomena.