Definition for theory:

From: wordnetweb.princeton.edu/perl/webwn

a well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena; “theories can incorporate facts and laws and tested hypotheses”;

From: Merriam-Webster.com Merriam-Webster Dictionary: Theory in Science

a scientific theory comprises a collection of concepts, including abstractions of observable phenomena expressed as quantifiable properties, together with rules (called scientific laws) that express relationships between observations of such concepts. A scientific theory is constructed to conform to available empirical data about such observations, and is put forth as a principle or body of principles for explaining a class of phenomena

Some important theories in science:

• kinetic molecular theory
• evoluion theory
• theory of relativity
• plate techtonics theory

I often hear those who talk about proving a theory.  An inevitable contradiction because:

Prove is an absolute

I prefer:

• make plausible
• draw conclusions
• make inferences
• verify
• determine validity
• interpret
• confirm
• demonstrate
• provide evidence
• authenticate

Therefore, I really do not like reading about the word ‘prove,’ especially in student work.  How do we effectively inform students about theories, most importantly that they are NOT conjecture, but are unifying concepts supported by FACT?