Science is really the art of predicting the future. What we consider "free will" is itself the same thing... our ability to predict the future. Therefore science is the mechanism through which we increase our ability to predict the future and thereby increase our free-will.
Lets consider the "scientific method" itself. Here is the scientific method in four steps (from this site), along with some commentary:
If the experiments bear out the hypothesis it may come to be regarded as a theory or law of nature (more on the concepts of hypothesis, model, theory and law below). If the experiments do not bear out the hypothesis, it must be rejected or modified. What is key in the description of the scientific method just given is the predictive power (the ability to get more out of the theory than you put in; see Barrow, 1991) of the hypothesis or theory, as tested by experiment. It is often said in science that theories can never be proved, only disproved. There is always the possibility that a new observation or a new experiment will conflict with a long-standing theory.
Here the emphasis is on creating a model of the world, but I'd like to drive home that creating the model is merely the means to the end -- predicting the future.