Ever since the National Museum of American History got its new name, the place has been rumbling like an expectant volcano.

The escalators are gone, moved off to the side. "It used to look like a museum of escalators when you came in," remarked Roger G. Kennedy, who brought the name and a lot of other ideas with him when he took over as director two years ago.

Next month most of the second floor will be closed, not to reopen until November, as a sweeping 10-year program gathers momentum, a program aimed at bringing direction and coherence to the place that, probably more than any other Smithsonian building, has deserved to be called the nation's attic.

The Franklin D. Roosevelt show will be removed, and its space will become the staging area for the first major new interpretive exhibit hall, "Travels Through Life in 18th Century America," plus a remarkable companion hall, "16 Elm Street: the Hart House."

The whole central area of the first floor will be turned into an orientation lobby and an old-fashioned ice cream parlor, far more elaborate than the present version. Big plans are in store for the giant American flag that greets visitors on the Mall side. (Already, interest in the flag has quadrupled simply because of a sign that tells people this is the original Star-Spangled Banner, the flag that inspired Francis Scott Key at Fort McHenry.)

With luck, these changes will be completed by 1984, the 20th anniversary of the Museum of History and Technology, to use its old name.

That's just the first stage.

Actually, Kennedy is looking ahead to 1992--the 500th anniversary of Columbus . . .

But maybe we need to slow down a little here. To start at the beginning, more or less:

It was a Smithsonian veteran, Frank Taylor, who saw the need as far back as the '30s for a museum of technology. The history part was added later, and right away the two disciplines clashed. Was it to be regular civil history, separate but equal, history and technology? Or history of technology? Gradually the lines blurred, and by the time historian Daniel Boorstin took over in 1969 a pattern had been set. It jelled firmly with the work on the bicentennial celebration, the 1876 show and the Nation of Nations.

"We were worried about the 'American' part because science and technology are essentially international in character," said department chairman Bernard S. Finn. "We didn't have the stuff to handle that, the exhibits would be a bit thin. So we said, let's go with our strength, which was the American stuff."

At the same time, the curators were beginning to see science in terms of the cultural and social history of America. Even now, a visitor can tell which permanent exhibits came before this new perception and which came after.

"Look at the railroad exhibit," Finn said, "the development of the generator, the story of mines and bridges, those big shows on the east end of the first floor. They're all in the grand tradition of the technical museum. There's nothing about social impact, just the history of machines. Then go to the maritime show next door, and the electricity exhibit, and the telephone. They don't deal as intensely with details, but they are concerned with the human impact."

Note: The Edison show, an exciting visual chronicle of an invention, its tribulations and proliferations, its vast effect on people's lives, replaces a dusty display of electrical meters and motors.

On the second floor, too, the old period rooms, the First Ladies Hall, contrast dramatically with the Nation of Nations and We the People displays.

"Fifteen years ago the FDR show would have been done as iconography, instead of as a study of how you made yourself into a public figure using media technology. We also see great changes in museum design techniques and color work, the silk screening, the blown-up graphics that we just slap on the wall. No plaques or borders. It's an explosion in graphics."

Some of these changes merely reflect the evolution of museum technique and are not unique to the Smithsonian. But some of the most interesting innovations flashed from the mind of Roger Kennedy, a former Ford Foundation vice president who--to the astonishment and admiration of anyone who has roamed those corridors of miscellany--actually seems to be making sense of the whole collection.

"We're a museum of ideas," he said. "We impose our will on refractory material and our job is to invite a sense of participation by most people. We ought to trigger the question, 'So what?' all the time."

The strategy is not simple. It is not merely to be a social history museum, but "to close the gap between what scholars are learning these days and what the public is getting. We want to be the national place where the best new learnings get to the people."

Note: A temporary show about the assembly line is in the works (consider the incalculable effect that this technique has had upon our consuming habits, our attitude to work, our daily lives). There will be a show on pain and what we have learned about it; on the Brooklyn Bridge; on alternatives for the future. The Haunted House

One project that Kennedy loves is the Hart house. A classic clapboard structure built in 1694 in Ipswich, Mass., it is not new to the museum. You have probably seen it without knowing it. For years it languished as a demonstration of carpentry methods: If you were really into building your own house, you could study the wooden skeleton and read the signs telling how window frames are installed and what a ridgepole does and so on. The house itself was invisible. All you saw were the parts.

Then Kennedy spotted the thing--and did a doubletake.

"It's a real house. It's haunted, you know. We had a dinner for some architects and various experts, and we brought them down there and I called for silence for 45 minutes. And we all sat there, in and around it, and let it talk to us."

Someone found an old chronology of the house, who lived in it and when, who stayed there during its years as an inn, what else it was used for. "It covers the whole American pageant," he mused, "the Underground Railway, revival meetings . . . We got Peter Wexler, the great theater designer, to do a book on it, which will be ready in a year or so. We'll have the public go through it in batches. We want it to be a living experience. We're not interested in passivity. It's not a picture. It's real."

The Hart house is one of the first projects in the 10-year plan. It will be permanent, part of a money-saving strategy to concentrate Smithsonian funds on permanent exhibits and to encourage private business firms to fund the temporary ones. The staff has learned to be very much on the alert against advertising gimmicks (following the debacle of the razor exhibit a few years ago which presented as the pinnacle of razor history the Gillette Trac 2--the show was funded by Gillette).

Michael Kerrigan, assistant director for exhibits and public spaces, also pointed out that more and more work is being done by Smithsonian craftsmen, cutting down on expensive custom work by outside contractors, who might or might not meet deadlines. "We're training new people all the time," he said. In the next five years, eight or more top staffers will retire and continuity is important right now. The second five years are still under study.

The orientation scheme is a good example of the museum's new sense of order. Influenced by recent informal polls of visitors, this special section at the entrance will explain the building's internal logic and may feature automated tour printouts.

"What you face when you come in from Constitution Avenue will be an exhibit of materials, the things that make up our world. One proposed title for the show: "Taking a Museum Apart." You also see the pendulum, which reminds you that all of us live on this planet whirling through space. On the left, the east wing shows how materials are used: You get into technology and industrialization. On the right, you see the thinking that those materials inspire, you get into science."

The central materials display will cover literally the stuff of the visible world. As the in-house proposal puts it, "The myriad artifacts of our culture can be seen as made up of materials from a very few families: natural petroforms, synthetic petroforms, metals, natural polymers and synthetic polymers. To successfully communicate this fundamental ordering to our visitors is nothing less than to give them the gift of seeing the world in an entirely new way."

One feature will be a cutaway marble column revealing the brick shoring, the steel armature. There will be fabrics and minerals, ceramics, alloys and plastics from Leo Baekeland's seminal 1907 Bakelite to nylon.

Beyond the pendulum will be the new Marriott-operated ice cream parlor, representing not only the human need for rest, food and fun, but also providing a place where a person can sit down and just think about all this stuff and what it means.

Fronted by a cast-iron arched facade, one of the last of its kind, resurrected from a Philadelphia storefront, the parlor will have ceiling fans, potted palms and little tables. Flanking it will be the Horn & Hardart Automat now in the cafeteria and the old-fashioned confectionery from upstairs. The Banner Yet Waves

At the Mall entrance, the Star-Spangled Banner will be refurbished, possibly by September. To preserve the tattered fabric, it will be hidden behind a curtain. Once an hour, the curtain will open, lights will go on and the National Anthem will play.

"After that, well, that's just the start. We'll have 'Travels Through the 19th and 20th Centuries.' We'll have a National Treasures Hall where you can take a foreign visitor, say, for a quick glance at some of our most famous artifacts: Lincoln's hat, Jefferson's desk and so on. We want to build a reception area off the First Ladies Hall, and open that up a little."

There will be vertical connections between floors too, he added. Directly above the first-floor exhibit of lathes, for instance, will be a second-floor display of early lathed furniture. As for the third floor, it will concentrate on communications and military history, plus some changing exhibits to attract an audience. There will also be changes in the Arts and Industries Building across the Mall, considered part of the American history complex. After its 1876 centennial show closes in 1984-85, it may be used to continue the story of industrial progress since 1850.

"Not just progress," commented the director. "That's the point. We want to reexamine the whole industrial process, speculate on the courses not taken, and why. Note: How did the gaslight industry react to Edison's electrical revolution? We look into changes in social styles. After all, the Argonne Lab is a long way from Ben Franklin's back yard."

Kennedy likes to say the museum is about process ("say, singing as a process, the science of singing") and kinesis. "That John Bull locomotive we have: We put it on the tracks alongside the C&O Canal and ran it. That's what it's for. Not to just sit there."

You could say the same thing about the museum.