Before revision: A scientific theory differs from a scientific fact or scientific law in that a theory explains "why" or "how", whereas a fact is a simple, basic observation and a law is an empirical description of a relationship between facts and/or other laws.
After revision: A scientific theory differs from a scientific fact or scientific law in that a theory seeks to explain "why" or "how", whereas a fact is a simple, basic observation and a law is an empirical description of a relationship between facts and/or other laws.