AS the initial enthusiasm of summer vacation ebbs into August daydreaming, it helps to have some get-up-and-go books on hand. Books that stimulate thought, that raise intriguing questions, that provide the kinds of practical suggestions youngsters may need to get started on a new project or two. The big outdoors begs to be explored this time of year, and a number of recent titles encourage readers to take a closer look at the soil beneath their feet and the sky above. These books also confirm the steadily improving quality of nonfiction writing for children. This year, in fact, a nonfiction work was recognized for literary merit as a Newbery honor book: Volcano: the Eruption and Healing of Mount St. Helens, by Patricia Lauber (Bradbury, New York, $14.95, 64 pages, ages 8 to 11).
The best of the new science books continues that tradition of excellence. In A Shovelful of Earth (Henry Holt & Co., New York, $12.95, 114 pages, ages 10 to 14), husband-and-wife authors Lorus J. Milne and Margery Milne offer a fascinating glimpse of the little-known world of soil-dwellers. With shovel in hand, these renowned naturalists go digging in North American forests and grasslands, tropical rain forests, and Arctic permafrost. They turn up bucketfuls of creatures and plants, from blind crayfish and burrowing owls to acrobatic moles and pixie-cup lichens that take a century or more to rise an inch above their rock base. Almost every page offers a few new facts. There are majestic viewpoints as well (``On any grassland, you can see in all directions, and feel taller than anywhere else in the world''), plus some adventurous asides (``As you climb any tall mountain ... you can pretend you are heading for the North Pole''), and a number of reminders of the fragility of nature (``You must respect the shallow soil high on a mountain'').
The authors' tone is welcoming, and illustrator Margaret La Farge builds on that approach with lovely pen-and-ink drawings of critters and their habitats.
How to Think Like a Scientist, by Stephen P. Kramer, illustrated by Felicia Bond (Crowell, New York, $11.50, 44 pages, ages 8 to 12), is a short but sweet investigation of how questions are answered using the ``scientific method.'' The author sets up one story after another to involve his readers and get them thinking logically.
He explains basic concepts like ``control groups'' in a low-key way and maintains a realistic tone (``Sometimes it is hard to decide what the results of an experiment mean''). It's a satisfying primer on the subject, with cartoony line drawings that add to the enjoyment.
It's Raining Cats and Dogs, by Franklyn M. Branley, illustrated by True Kelley (Houghton Mifflin, Boston, $12.95, 112 pages, ages 8 to 12), is another successful blend of interesting text and appealing artwork. Author Branley, who is astronomer emeritus and former chairman of the American Museum's Hayden Planetarium, takes on ``all kinds of weather and why we have it.''
He has a lifetime of anecdotes to draw on and a keen sense of the kinds of facts that spark inquisitive young minds. There's some history sprinkled about - record-breaking hailstorms, blizzards, and the like - but mostly this is a book that encourages budding scientists to figure things out for themselves (``... don't take our word for it'').
Branley proposes simple experiments to test the size and shape of raindrops, to make clouds, to measure wind speed. Some of the examples he uses are a bit macabre (a parachutist who froze over with ice and fell seven miles to his death, and a Park Ranger who's afraid of lightning), but overall it's a well-balanced approach to the oddities of the weather that surrounds us.
City Safaris: A Sierra Club Explorer's Guide to Urban Adventures for Grown-Ups and Kids, by Carolyn Shaffer and Erica Fielder (Sierra Club Books/distributed by Random House, New York, $19.95 cloth and $9.95 paper, 176 pages, ages 5 to 15), is written for adults to use with kids. Briefly, it's a compilation of games and activities that introduce youngsters to city life.
Environmental educators who have explored San Francisco with children for more than 10 years, the authors have a hands-on approach to urban discovery. As they take crayon rubbings of manhole covers and look for insect eggs along the untended edges of a parking lot beneath a freeway on-ramp, they make the case for the city as an ecological unit.
It's a fresh viewpoint that will appeal to children who live in town but long for the outdoor adventures that they associate with the suburbs. Now they, too, can brave the unknown elements as they go on treasure hunts, stake out produce markets, and grow container gardens and worm farms.
Exploring Summer, by Sandra Markle (Atheneum, New York, $14.95, 170 pages, ages 8 to 12), serves up more typical outdoor activities and games for children. Some, like building a sundial, playing shadow tag, and sending ``sun messages'' with a mirror, are hardly new. But there are probably enough interesting facts about how animals beat the heat and how early explorers crossed unknown deserts to keep kids reading. And if they hang in till the closing chapters of the book, they'll get to try their hands at making origami birds and drying their own raisins.
Children who'll be visiting a beach this summer will find a good companion in The Beachcomber's Book, by Bernice Kohn, illustrated by Arabelle Wheatley (Viking Kestrel, New York, $5.95 paperback, 96 pages, ages 8 and up). The author includes the usual beach fare - collecting shells and making pebble sculptures - but also takes several giant steps ahead as she encourages her readers to look closely at the many kinds of seaweed, egg cases, driftwood, coral, and beach glass that are tossed up on the shore. For every new ``find'' there are several inventive projects. The ``cookbook'' section even has recipes for beach-plum jelly and bayberry candles.
Thomas Y. Crowell, a division of Harper & Row, New York, has come up with several appealing new titles in its ``Let's-Read-and-Find-Out Science Books'' (ages 4 to 8). Ant Cities, by Arthur Dorros ($11.50, unpaged), gives kids a look inside the miles of tunnels and hundreds of rooms that harvester ants build beneath the ground. The author shows how each ant has a specific task and how, together, the ants keep their ``cities'' functioning. He even includes directions for building a simple ant farm in a jar.
The Moon Seems to Change, by Franklyn M. Branley, illustrated by Barbara and Ed Emberley ($12.95, 32 pages), is another Crowell title that ought to appeal to the young astronomer-in-waiting. Simple explanations of waning and waxing moons are accompanied by pleasing illustrations, and there's also an experiment youngsters can conduct on their own to show the phases of the moon.
For the very young naturalist, a new ``pop up'' field guide could provide hours of entertainment in a meadow or beside a pond. As they turn the pages of My First Insects, by Cecilia Fitzsimons (Harper & Row, $8.95, 10 pages, ages 5 to 9), children can gaze at larger-than-life-size spiders, bugs, and other crawlies - and then try to identify them in the wild. They're not for the timid, these tiger beetles and earwigs, and reading the text will require an adult's help. But it's a good start for the fearless explorer.
Diane Manuel reviews children's books for the Monitor.