SERIOUS SCIENCE

After Ms. D.'s class gets to participate in the big kids' science fair, the children develop just the exhibits that those familiar with the six earlier ``Adam Joshua'' books would expect- -Nelson hopes to prove that his fish has ESP; Sidney is growing cultures in his big brother's socks; and so on. Most of the episodic story is given to following the projects' progress, with added humor in the predictable interaction of familiar characters (Elliott steals Adam Joshua's idea of a solar system model, but AJ knows the subject better), fending off younger siblings (AJ's baby sister eats his planets), and the shenanigans of Ms. D`s boyish husband. With consistently perky dialogue, dozens of brief, funny incidents, and Gackenbach's appealing primary- graders sprinkled liberally throughout (plus the skeleton Mr. D. contributes adorning the jacket): an inviting entry in a popular series. (Fiction. 7-9)