A scientific theory is the framework for observations and facts. Theories may change, or the way that they are interpreted may change, but the facts themselves don't change. Scientific theories are based on natural and physical phenomena. A law is a description of an observed phenomenon in the natural world that holds true every time it is tested. It doesn't explain why something is true; it just states that it is true. A theory, on the other hand, explains observations that are gathered during the scientific process. Which is these demonstrates phenomena that are the basis of a theory?