Few writers have quite the handle Markle (Pioneering Frozen Worlds, p. 138, etc.) does on how kids think about science. For those who want to know why a dead fish floats or whether a warm worm stretches farther than a cold one, she provides brief puzzles, explanations, and simple experiments using household items to help explore these questions and more than 30 other icky science topics. The ideas are more appropriate for casual experimentation than for science fair projects; the explanations are brief, and there are seldom suggested follow-up activities. There's no obvious order to the presentation, and sometimes the text is more teasing than truthful: Children stretch a warm gummy worm, not a real one; ""Blow Up a Marshmallow!"" instructs readers to put a marshmallow in the microwave for 30 seconds and watch--hardly earthshaking. Not an essential purchase, but it has definite child-appeal.