Don't be bashful.  One good way is to visit the place offering the
position.  Ask questions of the staff about how science centers are
run....who does what....even offer to volunteer, if it uses volunteers.
Usually there's an annual report of some kind to be had, which ought to
tell a bit about staffing.

Then you might have an idea of what to expect if you decide to apply.  Hey,
there's nothing wrong with applying anyway -- it's good experience.  If
you're chosen for an interview, so much the better.  The interview is
better experience.