The word "theory" derives from the Greek word "theoria", meaning "to look at". 'Theory' has multiple meanings depending on the context of discussion. In everyday life, people use the word "theory" to signify "speculation", "opinion" or "hypothesis". However, "theories" do not necessarily mean facts or opinions. In the science field, scientists understand theories to be well established and verifiable models of interaction.
"The moment a person forms a theory, his imagination sees in every object only the traits which favor that theory." -Thomas Jefferson
The National Academy of Sciences describes the word theory in the following way: Some scientific explanations are so well established that no new evidence is likely to alter them. The explanation becomes a scientific theory. In everyday language a theory means a hunch or speculation. Not so in science. In science, the word theory refers to a comprehensive explanation of an important feature of nature that is supported by many facts gathered over time. Theories also allow scientists to make predictions about as yet unobserved phenomena.






