The Cosmological Milk Shake: A Semi-Serious Look at the Size of Things

This is Ehrlich's second collection of ``physics bites,'' short explications of abstruse-to-everyday concepts in the field. The author, who teaches at George Mason University, calls the ensemble ``the equivalent of an unconventional introductory course in physics.'' Encapsulating the idea of subatomic particles--or just the elusive idea of mass--in 750 words or so is a neat trick, but sometimes it's just that. These 135 breezy Q&As, most illustrated with cartoons by his son, Gary, would make ideal relief sidebars in a high school or undergrad physics text, but they do not of themselves make a book. Ehrlich's first collection of what might be called stand-up lab physics demonstrations, Turning the World Inside Out , had the same playfulness but with a purpose for teachers. In this collection he turned up the cute and weakened the fragile structure. Yet there's nothing wrong with humor in the service of science; it can even draw in readers who might otherwise fear the subject: ``Atoms, like people, can be stable or unstable.'' (July)