They can learn to use curve fitting techniques to recognize the kinds of functions that properly describe the physical system represented by a graph. This applies even to very complex systems such as motion or temperature vs. time relationships.
Students can strengthen their understanding of functions when their actions produce a graph.
In science, observations lead to hypotheses, whereas in mathematics courses applications seem to flow from decontextualized theory. In mathematics classes that do hands-on work, each experiment is chosen to clearly illustrate a particular function that is known in advance. Thus students have no need to review a multitude of possible mathematical functions in order to choose one or two to test in support of the prediction or hypothesis. In this approach, there is no advance clue as to what mathematical function will contribute to their work, although the groups often turn to mathematics for help with their final explanations. This provides a more open context for their use of mathematics.