The Magic Schoolbus Chapter Book #10: Expedition Down Under

Author: Joanna Cole
Lexile measure: 630
Language:  Acceptable, no swear words, no potty language.  There are some puns, which some kids may "get" and some may not.  Liberal use of Aussie dialect, but with definitions readily at hand.
Violence:  reference to predatorial/scavenging behavior of the Tasmanian devil, the children get chased by dingoes (may be scary for children who are afraid of dogs, but otherwise this scene really doesn't seem very scary--no growling or teeth baring or even barking).
Big Kid Mature Topics:   endangered animal species, oblique references to evolution/speciation (the reason why there are so many unique species is because Australia separated from Asia millions of years ago), transcontinental immigration's effect on the ecology of Australia.
Illustrations:  Black and white drawings every several pages.
Plot:  mildly complex

This is a fun one to read aloud if you like to do accents.  Its mostly about the animals of Australia, not so much about the social or cultural aspects of the country, which is great for younger kids who usually develop a sense of "history" after a sense of diversity in nature.  DD still really loves these books, even though I personally find them formulaic and only middling in terms of writing (not bad, just not very good).  I think the science concepts presented are not very simple, but it would still be an interesting book for younger kids.