When Staci Dawes took her East Valley Middle School health class to ExplorationWorks museum on Friday, she saw an amazing thing happen -- and it wasn't part of an exhibit.

A student in the class -- one who sometimes has had a hard time with book learning -- was so excited about the Helena museum's current Explore the Air exhibit that he ran around trying and taking in every exhibit.

He soaked up so much, he even started taking the other kids around and teaching them.

According to Kyle Huntley, science education specialist at ExplorationWorks, seeing things click in the minds of the museum's young visitors is an everyday occurrence at the museum.

"A lot of people get into education for those 'aha moments,.' " Huntley said. "We get a lot of those here. If they can feel it and do it, it stays with them."

Huntley about 3,900 children have come through the museum in school groups since it opened in November of last year, and he sees those "aha moments" just about every time a group comes through.

"It's been a pretty neat experience," Huntley said. "Their eyes light up."

Whether there is a long-lasting payoff in future scientists won't be known for a long time. But ExplorationWorks and other museums like it around the country are doing what they can to keep their wide-eyed young audiences interested.

To education experts, this is ''informal'' or ''free-choice'' science learning, which means it's happening outside of school.

This summer the National Academies, a congressionally chartered nonprofit group that advises the federal government, will release a report on what's known about the learning of science in such informal settings. That includes not only museums but also such places as zoos and aquariums.

The report comes as experts bemoan a lack of scientific education and literacy among Americans. They warn of a shortfall in homegrown engineers and scientists to keep the nation competitive, a general work force ill-equipped to function in an increasingly high-tech workplace, and a citizenry struggling to grasp complex public issues like stem cell research.

While that has led to calls for changes in schools, science museums -- broadly defined to include a range of science-oriented places to visit -- can also play a big role in teaching and promoting science to both children and adults, expert say.

Studies are showing that such institutions stimulate interest, awareness, knowledge and understanding, said David Ucko, an expert on informal learning at the National Science Foundation, which requested this summer's study.

''They're very useful,'' said Gerry Wheeler, executive director of the National Science Teachers Association. ''They're a valuable resource for making nature real to the young, hungry mind.''

The Association of Science-Technology Centers, which represents such institutions, counts 353 members in the United States. Apart from welcoming visitors, such centers often offer programs to schools, field trips, teacher workshops and after-school programs.

At the Liberty Science Center, which expects about 850,000 guests this year, visitors can walk a high steel beam in the skyscraper exhibit or practice laboratory procedures. ''With us, they're right up touching the science,'' says Jeff Osowski, the center's vice president of learning and teaching.

Seventy times a year, school groups and others gather in an auditorium to talk with surgeons as they perform operations on the other end of a live video link.

Bobbi Bremmer, who teaches high school science in Livingston, N.J., has taken her anatomy and physiology classes to these programs since 2003. The students have done many animal dissections and computer-generated virtual dissections. But it's still startling to see a power saw cut open a human rib cage, smoke rising from a cauterizing scalpel blade or urine coming from a newly transplanted kidney, she said.

''The students ask a lot of questions and get very frank answers from the doctors and the nurses,'' she said. ''For many of the students this experience can be life-altering, especially those who are considering a career in medicine and science.''

Discussion of why the patients needed surgery, with reasons including kidney disease or a bad diet or lack of exercise, is also eye-opening, Bremmer said. For many students, ''that is as important as any technical or book lesson, because the information is applicable to their families, friends and most of all, themselves,'' she said.

Museums ''have an enormous role to play'' in teaching children because they can offer experiences that are tough for schools to present, says George Hein, a professor emeritus at Lesley University in Cambridge, Mass., and author of the book ''Learning in the Museum.''

''You can actually do science. You can take prisms and mirrors and see what happens when you move light around,'' he said. Like music or sports, science has to be experienced firsthand to truly be understood, Hein said.

People don't necessarily gain a new insight every time they visit a museum, but the same can be said about time in most schools, Hein said. Comparing the two settings on learning-per-minute, he said, ''I think museums might be quite efficient.''

Another advantage of museums is that visitors can choose what to focus on, and that helps them learn more and retain it longer, says Oregon State University researcher John Falk. He added that museums benefit from a self-fulfilling prophecy: People expect to learn about science there, and so they do.

Research shows visitors do learn. One study, for example, focused on the effect of an exhibit about the human skeleton. When a visitor pedaled a stationary bicycle, a pane of glass showed an image of a skeleton within the visitor's reflection.

After that experience, 6- and 7-year-olds were handed an outline of the body and asked to draw a skeleton. Nearly all drew bones terminating at the joints -- a sharp contrast to the performance of other kids who didn't go through the exhibit. Remarkably, even eight months later, nearly all the museum visitors in the study still knew the relationship between bones and joints.

Falk found about a decade ago that the percentage of Los Angeles residents who could define homeostasis -- an organism's retaining of a stable internal environment -- rose to 12 percent from 5 percent after a local museum opened an exhibit that included that concept.

Almost everybody who responded correctly said they learned the definition in school, Falk said. But it evidently took a museum visit to bring that lesson back, which illustrates how museums can help people make better use of what they'd already learned, he said.

Or they can teach lessons with a delayed effect.

Falk said a woman told him about an exhibit she loved but didn't really understand when she was around age 5. To her, it was all about pushing a button to make a bunch of balls tumble through an array of pegs, ending up in a heap. Two decades later, when she was taking a statistics course, that childhood experience suddenly gave her an intuitive understanding of what the exhibit was really about: the statistical phenomenon of bell-shaped curves.

Still, much of the value of museums is about sparking interest and motivation toward science, rather than teaching specific facts, the science foundation's Ucko said. So kids may get hooked on dinosaurs or outer space at a museum, and then go study up on their own.

ExplorationWorks' Huntley said the museum has dealt with some abstract topics, such as in the Explore the Air exhibit which addresses Newton's law of gravity and other fundamentals of physics.

But exhibits that show how the laws of physics are put into practice by keeping a jumbo airliner afloat, or letting children feel the force of the air in an exhibit that

"Just having them exposed to that is just great," he said.

East Valley's Dawes said she sees evidence that the excitement from seeing the exhibits translates to the classroom.

She said when kids came into class Monday morning, they were still talking about the Friday field trip and what they learned.

She plans on making the museum's exhibits a tradition in her class.

"It's a great opportunity for a lot of these kids to go," she said. "Many of them had never gone before. It's great for community building."

Click here to visit the Web site of Helena'sExplorationWorks museum, Liberty Science Center, Exploratorium and Association of Science-Technology Centers.