How scientific laws such as Newtons gravity differ from scientific theories?
They don’t. You can’t prove a scientific theory. However, when we get a couple of centuries of evidence behind them, we get pretty confident that they’re correct. The only difference between a scientific “law” and a scientific theory is the name it is given in the popular imagination. As a matter of fact, we know for a fact Newton’s theory of gravitation is incorrect. The more accurate theory is General Relativity, and the most famous prediction where GR gets it right and Newton gets it wrong is in the orbit of Mercury. However, the errors that Newton’s theory makes are so tiny that for all practical purposes in daily usage, it is “correct”. You have to have extremely sensitive experiments to detect the discrepancies.
