all scientific laws are theories

Laws are formulations that describe what happens. Theories are rather larger bodies of knowledge that can include laws, and which attempt to explain why or how things happen.

For example - Newton's law of universal gravitation states simply that "Every point mass attracts every single other point mass by a force pointing along the line intersecting both points. The force is proportional to the product of the two masses and inversely proportional to the square of the distance between them" or, as an equation,

F = G (m1 . m 2) / r²

The theory of gravity, however, attempts to describe the nature of gravity, how it arises, how it works on the very largest and very smallest scales, how it propagates through space, and so on.