Final answer:
A hypothesis is a tentative explanation used to begin an investigation, while a scientific law is a description of a pattern in nature that is true in all circumstances that have been studied.
Step-by-step explanation:
A hypothesis is a tentative explanation for an observation or set of observations, used to begin an investigation. It is a testable idea that helps scientists understand and explain a specific phenomenon. For example, the hypothesis that the universe began in a big bang is a scientific theory because it has been extensively tested and supported by evidence.
On the other hand, a scientific law is a description of a pattern in nature that is true in all circumstances that have been studied. It is a concise statement or equation that represents a fundamental principle. Isaac Newton's discovery that every action has an equal and opposite reaction is an example of a scientific law in physics.