SCIENCE MATTERS Achieving Scientific Literacy By Robert M. Hazen and James Trefil Doubleday. 295 pp. $19.95

WHY IS IT hotter in summer than in winter? If you're the sort of person who can tie his own shoes without much help, that question shouldn't really boggle your brain. Yet in a random sampling of Harvard's 1987 graduates, only one out of 10 answered correctly.

Depressing? Try this: A recent survey of George Mason University seniors found that half didn't know the difference between an atom and a molecule. Thanks to the pandemic dumbing-down of American culture, experts now estimate that more than 93 percent of the nation's adults are scientifically illiterate; that is, they lack the basic conceptual tools needed to make responsible decisions in our increasingly science-driven society.

Does it matter? Not much -- as long as you're prepared to start calling California "New Osaka," happy to be snookered by every techno-boondoggle touted by Congress, and content to waddle into the 21st century with about half the intelligence of the average crock-pot. If not, try turning off "Roseanne" and picking up this compact and amiable volume. There are several books of the general how-stuff-works persuasion on the market these days, but for overall page-turning readability, Science Matters is as good as they get.

Dedicated to providing the "constellations of basic facts and concepts that you need to understand the scientific issues of the day," the book is based on "one of academe's best-kept secrets: The basic ideas underlying all science are simple."

True enough. But explicating them without stupefying readers is remarkably difficult. Happily, the authors -- Robert "The Breakthrough" Hazen and James "Dictionary of Cultural Literacy" Trefil -- are proven veterans of the popular press. Moreover, both are professors at George Mason University, which means they have spent enough lectern time in front of semi-comatose undergraduates to know how to make potentially intimidating ideas inviting and even downright user-chummy.

The exposition is arranged into 18 "general principles," and progresses from fundamentals (basic laws of energy transfer, architecture of the atom) to combinations of those processes (machinery, geology, cell structure) to complex systems (ecology and evolution). Each chapter has a bit of history and an illustration or two; and each can be read and enjoyed independently. Taken together, they constitute an artfully compacted overview of everything you should have learned in high school.

To "comprehend" something means -- literally -- to grasp it, and our minds seem to be configured to respond well to things we can visualize. Hazen and Trefil have a particular genius for picturing even formidably abstract ideas in concrete images. They explain the principles of electromagnetism by referring to magnets on refrigerator doors or static electricity in combs. They depict a water molecule on the Mickey Mouse model ("the oxygen is Mickey's negatively charged head, while the {two hydrogen atoms} form the ears"). Nuclear warheads are "each no larger than a bag of groceries."; and black holes, "a mile or more across, are supposed to litter the galaxy like junk cars on a country road." An ordinary atom "is almost all empty space. If the nucleus of a uranium atom were a bowling ball sitting in front of you right now, the electrons in orbit would be like 92 grains of sand scattered over an area equal to a good-sized city."

Throughout, the prose is lucid and lively. For example, this disquisition on the sodality of life: "All of earth's living things, from slime mold to tea roses to humpback whales, have the exact same DNA-based genetic code, with the molecules following right-handed (never left-handed) spirals." Or this, on the scientific definition of work, which is force applied through distance: "No matter how much effort you expend, if nothing moves, no work is done. Physicists can thus actually prove that bricklayers do more work than lawyers."

Though admirably value-free for the most part, the presentation gets gratuitously partisan at times. The authors take a swipe at creationism ("a form of religion" that is "one of the greatest threats to the science education of America's children"); proffer the unsupported assertion that the human genome project "should be well worth the initial cost"; and are egregiously bullish on nuclear energy. This gets inadvertently comic in dismissing the "China syndrome" threat: "In reality, nuclear fuel never gets hot enough to melt very far through the earth."

These, however, are minor lapses, and book's only substantial shortcoming is exactly that: In many places, the explanations simply come out too short. Some ideas would require only two or three more sentences to make them fully comprehensible. (Why does ultraviolet light cause fluorescence? What exactly do accelerator particle collisions accomplish? How do "saturated" and "unsaturated" fats stick to different kinds of things? Why do DNA molecules form into "base pairs"?) Some others might have cost a few more pages and a diagram or two. (Why do crystals vibrate, and how do we use them? How do waves interact in "interference" patterns? How does photosynthesis store energy?)

Hazen is an earth scientist, Trefil a physicist; not surprisingly, their book devotes most of its space to "hard" disciplines such as physics, chemistry, astronomy and geology, and comparatively little to life sciences. This is as it should be. The vast bulk of what passes for "science" coverage in periodicals and -- rarely -- on television is actually medical news. (And there's barely enough of that to counteract the anti-science effects of voodoo rubbish like horoscope features, which newspapers continue to publish as if they were "true.") As a result, readers can get a fairly good idea of how AIDS develops or how cholesterol clogs arteries; but not three in 100 can explain how their quartz watches, VCRs or catalytic converters work.

Does it matter? You bet your life. Curt Suplee covers science for the national desk of The Washington Post.