system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is the difference between theory and law in science?

For example: theory of relativity and law of gravity.  
I googled this but answer wasn’t clear to me.
gpt
In science a law is a **description** of an observed phenomenon. Often this takes the form of a mathematical equation describing the relationship between observed phenomenon.

A theory in contrast is an **explanation** of why a phenomenon exists or what causes it. They run the range of completely untested guesses to enormously supported explanations accepted by basically everyone as correct; there is no "graduation" from one thing to another via consensus or evidential support, a theory is always a theory no matter how well or little it is accepted.