BETWEEN SCIENCE and Rodney Dangerfield, it isn't clear which or who deserves more pity. The sad- eyed comedian, of course, doesn't get much respect, but he does have a rather large following. By contrast, the subject that I know and love gets oodles of respect, but it doesn't have many fans. For example, according to a recent survey by the Children's Television Workshop, most 8-to 12-year- olds think of science as 'intellectually difficult, physically dangerous, and requiring long years of training." Most of the youngsters respected scientists for their knowledge, inventions and "new cures" for diseases, but very few of them were interested in becoming scientists themselves.

Adding to the pity, the vast majority of children's science books, I find, are just as dull and formidable as science is widely perceived to be. This short list of books includes the well-written exceptions among this season's relatively poor crop. The first pair, I believe, make science accessible by illustrating how it can answer questions any normal youngster would find interesting. And the second pair make science not merely accessible, but also fun, by involving the young reader in activities that are entertaining and readily doable.

In Tales Mummies Tell, Patricia Lauber acquaints the young reader with paleontology, biology, archaeology, physics and anthropology by showing how these subjects are used to solve wide-ranging mysteries about our past. By choosing mummies as her focus, moreover, and telling her story like a good mystery writer, Lauber has increased the odds of attracting a sizeable readership.

For starters, she explains that though "the word mummies usually makes people think of ancient Egyptians wrapped in bands of linen . . . they are far from being the only ones." For example, there is "Dima," the 10,000-year-old frozen corpse of a baby wooly mammoth, discovered buried in Siberia in 1977; the Chinese lady from Hunan, whose 2,100-year-old remains are so well preserved that her flesh is still elastic; and the mysterious "Bog Bodies," the mummies of people who were trussed up and tossed into the peat bogs of Denmark, apparently either as villains or as sacrifices to a Nature god.

Each mummy tells "of a brief life in a world that vanished long ago," Lauber explains, and "that is one of the chief reasons why scientists study the many kinds of mummies they have found." With her simple and engaging explanations of the lavish inferences scientists are able to make from such studies, Lauber makes science more attractive and not, thank goodness, merely more respectworthy. For example, in referring to the mummy of an Egyptian teenager, known only as Number 1770, Lauber tells us that: "If a person always breathes through the mouth, the gums around the upper front teeth become irritated and the bone behind them pitted. Pits in the bone of 1770's mouth showed that she had indeed breathed through her mouth."

Whereas Lauber is concerned with mysteries unearthed from the past, award-winning author Roy Gallant applies himself in 101 Questions and Answers about the Universe, to demystifying the secrets overhead, in the heavens. As director of the Southworth Planetarium in Maine, Gallant explains, he has been asked every question in the book "one or more times by elementary school groups."

Doubtless this experience accounts for the refinement of his answers to such questions as: "Why is the sky blue?" (because the atmosphere scatters the sun's blue light most of all); "What planets have the biggest moons?" (Jupiter, Saturn and Neptune); and "What makes the stars twinkle?" (the movement of air currents in the atmosphere). My hunch is that many parents and teachers, as well as youngsters, will find their curiosity sated by Gallant's clearly -- and deftly -- written explanations.

It is less certain, I regret to say, whether they will have their imaginations challenged in the process. My concern is that Gallant's answers are so refined and close-ended that they do not encourage the reader to contemplate the subtleties or uncertainties of speculative questions, such as "How was earth made?" or "What's infinity, and how big is it?" Because of this, I fear, Gallant's otherwise excellent book is likely to invite the unwarranted impression among many of his younger readers that science has all the answers.

BY COMPARISON, Paul Janeczko's discussions in Loads of Codes and Secret Ciphers are nearly always open-ended, constantly beckoning readers to use their imagination to create codes and ciphers of their own. For example, in his discussion of pictographs, such as the kind early American Indians used in cave paintings, Janeczko finishes by asking: "How would you use a picture to communicate an abstract idea or feeling? What picture would communicate love or sadness or joy?"

In five fast-paced chapters, Janeczko reveals the science and art of cryptography, and also its associated history of espionage and intrigue. For example, he not only explains that a substitution cipher is produced when "one symbol is substituted for another," he shows you the specific substitution cipher that Mary, Queen of Scots used in confiding to friends her ill-fated plot to murder Queen Elizabeth I. "Slowly Elizabeth gathered information on her cousin's plot to assassinate her," relates Janeczko, and eventually "Mary was brought to trial and convicted on the evidence of her secret messages; then she was beheaded."

Though Janeczko's book might well be recommended alone for being such a well- written, entertaining primer on cryptography, it is more than that. In preparing his young readers to learn cryptanalysis (the process of breaking codes and ciphers), for example, Janeczko is also preparing them for the scientific method. "It will take some luck, true, but it will also take good old-fashioned thinking," he writes, "the stuff Sherlock Holmes called 'elementary.' You'll have some false starts and you'll run down some blind alleys, but if you stick with it, you'll be able to attack a message and crack it without much trouble." Louis Pasteur, Thomas Edison and Albert Einstein could not have said it better.

Introducing youngsters to the scientific method of inquiry by entertaining them is also what Vicki Cobb does so effectively in Chemically Active! On the surface, this work appears to be just another children's book on chemical magic, but it isn't. Cobb's purpose is not merely to dazzle her young readers with magenta-colored solutions and snow- white precipitates, but to actually teach them some real chemistry. "I'm betting that this kind of fun will make you want to know more about what's really happening in the bowl or jar," she writes, because ultimately "understanding science, doing science, is even more fun than just making mysterious things happen."

With infectious enthusiasm, Cobb chats her way through explanations of such formidable topics as photochemistry, electrolysis, chromatography and covalent bonding. In the process, she works against the possibility of losing her readers by guiding them through experiments that illustrate her main points and that require only household items. There is, for example, the "Essence of Cabbage" experiment in her discussion on acids and bases; the "Splitting Water" experiment in the section on electrolysis; and the "Water-to-Wine-to Water Gambit" experiment, which illustrates her explanation of chemical indicators.

Were it not that Cobb's text is so captivating and her son's illustrations so charming, I'd be tempted to call Chemically Active! a textbook. In any case, it ought to be required reading. It is instructive, up-to-date and thorough. And above all, it is fun -- just like Rodney.