Sometimes we see and hear scientific words buzzing
around the Internet or in the news--like the theory of evolution or the
law of gravity, but what makes these things different and what do words
like hypothesis, theory, and law mean?
These words have a specific meaning in science.
Outside of science, you might say something is “just a theory,” meaning
it is an assumption that may or may not be true. In science, a theory is
an explanation that generally is accepted to be true. We will take a
closer look at these important and commonly misused terms.
A hypothesis is an educated guess based on
observation. Usually, a hypothesis can be supported or refuted through
experimentation or more observation. It provides a suggested solution
based on evidence. In science, experimenters may test and reject several
hypotheses before solving the problem. Two “rules” scientists follow
when choosing a scientific hypothesis are that they must be testable and
falsifiable. Science proceeds by making observations of nature. If a
hypothesis does not generate any observational tests, there is nothing
that a scientist can do with it.
Next, a scientific hypothesis must be testable, but
there is a much stronger requirement that a testable hypothesis must
meet before it can really be considered scientific. It must be
falsifiable. A hypothesis can be disproven, but not proven to be true.
In order to prove something to be true, a scientist would have to test
absolutely every opposing hypothesis, and they would have to be
disproved. This is impossible to achieve. If a hypothesis or group of
hypotheses receive enough support then it can be considered a theory.
A scientific theory summarizes a hypothesis or
group of hypotheses that have been supported with repeated testing. A
theory is only valid as long as there is no evidence to dispute it.
Therefore, theories can be disproven. Basically, if enough evidence
accumulates to support a hypothesis, then the hypothesis can become
accepted as a good explanation of an observed phenomenon. One definition
of a theory is that it is an accepted hypothesis.
A scientific law is a statement of fact meant to
describe, in concise terms, an action or set of actions. It is generally
accepted to be true and universal, and can sometimes be expressed
mathematically. Scientific laws do not complex external proofs; they are
accepted at face value because they have always been observed to be
true. Some scientific laws include the law of gravity, Newton’s laws of
motion, and the laws of thermodynamics.