Identify and discuss the differences between the terms ‘theories,’ ‘laws,’ and ‘hypotheses.’ Describe ‘controlled conditions.’

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caledon eNotes educator| Certified Educator

LawsThe term "Law" in science is a debatable one. A good scientist would say that the term "Law" and its implications are inherently unscientific and do not belong in a scientific dialogue. This is because a scientist should always be open to the possibility of error or contradiction; calling something a Law, in the sense that it is a rule that is never broken, is an inherently unscientific premise. Even if we are 99.9% certain that something will be a certain way, good science does not make the leap of presumption to 100%.

However, there are less volatile definitions of the term Law. Most of the time, we use the term more loosely, to suggest something which has been repeatedly observed and confirmed through those observations, and which we assume to be true under future conditions. Observations which describe a "what", and not a ""how" or "why" are also called Laws, because they do not involve a hypothesis.

HypothesesSometimes hypotheses are called "educated guesses". A good hypothesis is a proposal or prediction that can be tested, measured, repeated by others, and independently confirmed. A complete hypothesis might say "X is hypothesized to be red; this will be tested by placing the object in a spectrometer and analyzing its light spectrum, and comparing that spectrum to the red range of light wavelengths."

TheoryA theory is a hypothesis that has been repeatedly tested and shown to be consistent. The hypothesis does not necessarily have to be retained in an unaltered form; in fact many hypotheses undergo revision on their way to being considered a theory. There is no definite line between what is considered a theory and a hypothesis; a hypothesis can be tested 5 or 500 times and not necessarily be a theory. Status as a theory is largely a result of the agreement of the relevant academic community.

Controlled ConditionsThe only thing that all "controlled conditions" have in common is that they are designed by humans toward a specific intention. The world and its interactions are complex; by limiting those interactions by controlling them artificially, we can get a better idea of which things affect each other and which do not. Controlled conditions often seek to reduce or eliminate variety so that only the things that remain are available to influence one another.

kfrazier0126 eNotes educator| Certified Educator

A theory is an idea that a scientist has that has.  There is evidence that goes against it, but there may be other ways to explain the reason for the phenomenon. For example, the big bang theory.

A law is a rule that has never been disproven.  It has strong support and is followed every time.  Think of the law of gravity, or Newton's laws.

A hypothesis is an educated guess or prediction to the outcome of an experiment or event.  When you perform an experiment, your teacher will probably ask you to make a hypothesis to what the results of your experiment will be.  A hypothesis generally has not yet been tested, and will be supported or unsupported based on the results of experimentation.

If a hypothesis is repeatedly tested, it has the possibility to become a theory, or a law.  It must also be accepted by the scientific community to be considered such.