I would say ALL of science, not just "much" of it. The difference between math and science is that in science, hard reality is the bottom line. No matter how good your model, how much data you have, what p values you get against simulations - hard reality wins everytime. Thats also why the so called soft "sciences" aren't sciences at all: they are not dealing with hard, objective reality at all.

Math + real world observation -> science