This picture book for older children blends this well-known author's fiction and non-fiction talents to convey facts about water supply while telling a mildly amusing tale about a wacky field trip. Ms. Frizzle is the strangest teacher in school: she wears dresses in reptile prints, makes her students read five science books a week, and insists on such weird projects as making clay models of garbage dumps. The day of the field trip, her bus ascends to a cloud, from which she and her class disembark, clad suddenly in scuba gear, for a trip through a reservoir system: through water mains, water pipes and out again (in shrunken size) through the faucet of the school's girls' bathroom. Along the way, everyone gets a clear idea of a reservoir-based water system, plus 10 basic facts about water. Cole concludes with a tongue-in-cheek list of things that happened in the book which couldn't really happen, for those who don't like mixing science with fiction. Although classified as fiction, the story hardly stands on its own, but as an introduction to water and water utility systems, it is entertaining and understandable. Its best use would he in classrooms, where the students could enjoy both its sly humor and useful information.