Yes, science is hard. But science is also rewarding. Laser guns, winged octopuses, robot arms that house a time machine, do you think that stuff comes from NATURE? Give 'em a love of the field, they can suffer through the math.
NSI Smithsonian site
My boys (4 and 7) LOVED the rock and gem dig, although you don't get one of each (which it seems to suggest) and what you do get a tiny little chips of rock (most about the size of a fingernail), still, they LOVED the dig.