She's an engineer. She probably doesn't even know what "pH balance" actually means, somebody just told her that "this in hair good, that in hair bad". She's probably never even read a peer-reviewed journal. And she doesn't need to.
Of course all this was at some point discovered by scientific researchers, but the research itself was "fun" in the way most kids perceive fun. It was probably hard work, and boring.
Science is study, discovery and hard work. Engineering is applying the results of that study.