When science buffs Bill and Bobbie Adolfson of Fairfax decided to help their son and daughter learn geography, they headed for the kitchen and got out some dough, pizza sauceand cheese.

Before long, the family of four had constructed an edible relief map of the United States, complete with gooey cheese mountains and pepperoni-studded cities.

"The shape was okay, but everything kind of melted down after awhile," recalls Bobbie Adolfson, a 37-year-old statistical assistant. "We had a lot of fun doing it. We did a couple of other countries after that."

But the Adolfsons could not live by pizza geography alone. Soon they began wrapping their children's arms with woolen scarves, newspapers, plastic and even popcorn before plunging them into ice-cold water. For Erik, 10, and Kristin, 6, it was a hands-on lesson in insulation.

That was two years ago. Today, instructions for pizza geography and 11 other offbeat family science projects designed by the Smithsonian Family Learning Project -- and tested by the Adolfsons and about 2,000 other families around the country -- are available to the general public in Science Calendar 1985. The calendar, first of a series, is designed to help families learn science at home through everyday household items.

Among other monthly projects were paper made from grass clippings and processed in a blender; a sound machine made from wood and fishing line; a sun dial made of cardboard and pins; and a solar greenhouse made with soup cans and plastic bags.

"What this calendar suggests is that you don't have to be an expert to learn science. Anybody can learn science at home," says Smithsonian educational research director and calendar designer John Falk.

Most parents, he says, assume that schools will teach their children all the science they need to know, which is not necessarily so. He and other educators also point out that young children are most curious about their natural world and most receptive to learning science.

High-school science courses, according to a 1983 National Science Foundation report, "Educating Americans for the 21st Century," are generally designed to prepare students for college rather than to impart a broad understanding of the complex technological world they will inherit. And about 30 percent of high school science and math teachers are unqualified to teach their subjects because they have not taken enough courses themselves, claims John Fowler, special projects director of the National Science Teachers Association.

Despite a national effort to improve the quality of science education through such incentives as the Presidential Awards for Excellence in Science and Mathematics Teaching and legislative mandates in some states to increase the number of required science courses, the problem is "massive," says Fowler. "To really bring about a change in science education is going to take at least a decade."

In the meantime, he and other educators urge parents to work with their children at home and to persuade their school boards to offer more science, particularly at the elementary level.

"The parent who knows science can do a lot and does," says Fowler. "You walk through the woods and you point out different trees. You look at the formation of clouds in the sky and you comment on why they're up there. You tell kids how the moon goes through phases."

It's a mistake to think that only those youngsters who may go on to major in science or engineering in college need to learn much about chemistry, physics and biology, says Kathleen Sweeney-Hammond, a chemistry teacher at the Maret School in Washington and a recent recipient of the Presidential Award for Excellence.

"There are so many important ethical issues facing our technological society, such as toxic waste disposal, genetic engineering and nuclear weapons," she says. "American citizens must have some understanding of science to vote on the issues." Parents should try to get their kids "hooked" on science during the middle-school years, she says, when they are most interested in exploring the world of bugs and trees. Along with encouraging kids to do experiments at home -- "they won't blow anything up" -- she advises nurturing their interest through visits to Washington museums.

As part of their "hands-on approach" to teaching science at home, Dean and Julie Borden recently brought their three young children from Plano, Texas, to visit the Air and Space Museum, among others.

The Bordens, who decided to teach their middle child, Mark, 6, at home rather than send him to school, wanted him and his brother and sister to see actual planes and spaceships instead of just read about them.

"So much of what children learn about the world in school is from books and lectures," says Dean Borden, a 36-year-old physician.

When Julie Borden, 34, taught their son Mark about the change of seasons this fall, she took him into the countryside to gather leaves. Soon they were talking about the equinox. And when they returned home, she got out a globe to show Mark how the seasons change as the earth revolves around the sun.

While parents hardly have to take their children out of school to see that they get a good education, they must recognize, says the Smithsonian's Falk, that most of what children learn about science is learned outside of the classroom. "If you take the entire lifetime of an individual, those years in school represent a relatively modest -- an important, but modest -- chunk of one's life."

Although people learn all the time, little research is available on how average families learn outside of the classroom. Each family, says Falk, has a different style.

"There are some parents who take a child to a museum and really try and read the labels for the child and define the direction of that visit. There are other families who go through a museum, where the children and the adults seem to ignore one another. They check back every once in a while. But the children go off and do their thing and the adults do their thing.

"You might initially say, 'Well, that first parent is really taking this seriously as an educational experience and definitely giving direction to the learning.' " But one could also argue, he says, that the less involved parents are providing good role models by showing they enjoy learning, too.

"So which is better? They both have their value."

The most important thing parents can do, science educators agree, is to create an atmosphere which encourages children to want to learn.

"When the elementary school kid comes home and asks a question about science, don't say 'I don't know,' " says Fowler. "Say: 'I don't know but let's find out.' I think the main thing anybody can do for kids is to help them keep their curiosity.