Two new museums open in the Washington area during the last year or so.

One, in suburban Virginia a good hour's drive from the Mall, lives up to hopeful expectations: In the eight months the Smithsonian's Steven F. Udvar-Hazy Center has been open, 1.3 million people have flocked to this branch of the National Air and Space Museum at Dulles Airport.

The other museum, smack downtown and across the street from the new Convention Center, falters after just 14 months of operation: As my colleague Jacqueline Trescott reported recently, the City Museum of Washington has pulled in only 33,000 people, somewhere between one-third and one-tenth the numbers forecast for it, depending on the forecaster.

The reason for the difference? Wondrous stuff to look at -- or a puzzling lack of such, at the City Museum.

Udvar-Hazy is a mammoth, bare-bones hangar stuffed with about 90 full-size flying machines, from a sleek Blackbird spy plane to the cutesy-pie, driveway-size Rutan Vari-Eze. (An additional 100 or so planes are on the way.) The aircraft sit on the concrete floor or hang from wires overhead, with enough space left over for glass cases holding all the fascinating extra bits -- gloves and goggles and airplane models and aerial cameras -- that come with flight.

The City Museum, in a lovely vintage building, is a carefully thought-through exercise in storytelling, with acres of pedagogic texts and high-design graphics. Displays are meant to lead you by the nose around and through the social history of Washington. Oh yeah. There are a few artifacts on view as well: A handful of ancient pots and pans, a couple of neat firemen's helmets, vintage photographs.

Udvar-Hazy causes goose bumps. The City Museum, heartbreakingly well-intentioned, is a snore.

I don't think this is just an issue of subject matter. Some people may find airplanes and spaceships an obvious draw compared with history and urban space. But as a former historian, obsessive cityphile and relative newcomer to Washington -- and an artsy aesthete rather than a techno-jock -- my first impulse was just the reverse: I rushed to visit the City Museum when it opened; I got to Udvar-Hazy only last week. Yet for all my peculiar biases, I still agree with the average Joes who have been voting with their feet. I would head back out to see those planes tomorrow -- and the next day, and the next. I have no immediate plans to go back to the City Museum, or to push it on family and friends who visit.

Udvar-Hazy understands what museums, and the objects they contain, can do; intuitively at least, it also understands museum history. The City Museum is a shining example of a new, failed model for what museums are.

Udvar-Hazy understands that museums are, first and foremost, about fascinating objects. They have to have a "wowie-zowie factor," in the words of Peter Jakab, chairman of the aeronautics division at Air and Space. At Udvar-Hazy, that factor depends squarely on the collection on display; the project cost $300 million because its exhibits are more than a little oversize, rather than because they've been gussied up with sound and lights.

Jakab argues strongly -- over any objection I can mount -- that museums have to tell stories, even teach lessons, about the subjects that they're built around. But he also believes that the stories and lessons have to grow out of the objects that museums collect. That puts him plumb in the mainstream of museum history.

Museums started out as Renaissance Wunderkammern -- private "wonder chambers" where the well-heeled could display their collections of wondrous stuff, whether made by nature or by man. They were about the pleasure to be had from the glories of God-given and man-made plenty. It turned out that one way to enjoy and profit from that plenty was to catalogue it, sort it out, find the laws and regularities behind it -- to learn from it and all about it. Most of the natural sciences and many of the humanities took off from those Renaissance treasure chests. The private displays themselves eventually evolved into public museums -- of art and history and science.

But that doesn't mean that today's museums should be collapsed into the academic and pedagogic disciplines that the Wunderkammern launched. Museums can't simply become teaching tools; they have to preserve their roots as places to wonder at and about stuff.

If your real goal is to learn about a subject, there's no point going to a museum. It takes three hours, probably more, to get to a museum and then give it a decent once-over. In that time, you could learn more by staying at home and reading a book or surfing a few good Web sites. You go to a museum because extraordinary objects have a power that goes way beyond the specific lessons they can teach.

Likewise, there's no point starting a museum if you don't have fascinating stuff to put in it. For a museum to work, the objects can't be optional illustrations to a schoolroom lesson; they have to be the reason for the museum's existence.

The objects on view don't have to mark great moments in art or science to do the trick. As a young teenager, I remember being thrilled by a visit to a Museum of the Hunt in rural France, though I was a city kid who'd never held a gun or killed a beast. Last month, I wandered into the Museum of International Folk Art in Santa Fe, though I've always been a distinctly fine-art kind of guy. And I found a jaw-dropping accumulation of objects -- 125,000 of them -- whose existence I'd barely guessed at before. It wasn't that I went in feeling a need for a lesson in anthropology and the material culture of foreign peoples. And I can't say that I came out a much better anthropologist or folklorist than I went in; the museum keeps its pedagogic aids to a blissful minimum. But I came out overjoyed at having come face-to-face with fascinating chunks of the material world I'd never come across before.

That's probably close to the experience that most non-experts come away with from even the greatest art museum. It's the overall effect and novelty of the art experience that probably matters most to the neophyte. Recognizing and appreciating the excellence of a few officially certified masterpieces -- masterpieces the average Joe might not even spontaneously recognize as such -- must come a distant second.

Humans are hard-wired to care about the fabric of the world around them, and to want to look and sniff and taste and tug at it, as much as any dog does. That's the instinct that kept us alive on the African savanna, and that brought us where we are today. That's the instinct that museums have to ride piggyback on.

The great museums of the world all function first and foremost as storerooms for amazing stuff our culture cannot bear to throw away. Then our experience of that stuff can be enhanced by thoughtful, friendly curating.

That's how the Udvar-Hazy Center came to be: The Smithsonian had about 250 more amazing aircraft on its hands than it had room to show. For years they were stored in a facility in Suitland that was open only by appointment. Udvar-Hazy was designed to give the public open access to that aeronautic plenty, with educational "enhancements" to be added over time, as the budget allows. (The entire Smithsonian is now testing a system of hand-held electronic gizmos that should eventually allow visitors to get as much -- or as little -- information as they want about any object that catches their eye. A recent prototype had potential, but was still closer to a toddler's board-book than to the open-ended encyclopedia it needs to be.)

The City Museum was founded with the specific mission of teaching lessons about Washington. The fact that it also displays a collection of objects is a kind of afterthought: The museum wants to tell a story, and the collections were "a way to do it," according to exhibitions curator Jill Connors-Joyner. There are, in fact, more objects on view in the museum than you first see; in the display called "Washington Perspectives," they're tucked into drawers that you can pull out, if the fancy grabs you. But that gives a sense that the objects in the drawers are an embarrassment to be hidden away -- a potential distraction from the history lesson that Teacher is trying to drum into you, rather than the backbone that it's built on. And to the extent that this is true, the City Museum was doomed to stumble from the day it was conceived.

The only truly wondrous object that it has on show is the Beaux-Arts building that houses it -- and that building could house any number of other institutions without losing its appeal.

Unfortunately, the future of museums seems to be tending toward more City Museums and fewer Udvar-Hazys. Curators at the City Museum just won an award from their peers for that "Washington Perspectives" room.

Realizing that people learn from objects, and that museums have always made that learning possible, curators have come to imagine that the learning is the ultimate goal. Objects are thought of as handy tools for getting there. In art museums as well as museums of history and science, flat-footed pedagogy is taking the place of Wunderkammer wonder.

In many of the latest displays at the Smithsonian's non-art museums, and even in the occasional show at the National Gallery, there's a feeling that the objects are there to help a curator feed answers to the public. Whereas great museums used to believe in the essential virtue of the objects they showed: They imagined that their simple plenitude of objects would spark new questions, and awe.

The Steven F. Udvar-Hazy Center, which has drawn 1.3 million people in eight months, understands that museums are, above all, about fascinating objects . . . . . . while the City Museum of Washington, which counted Cathy McKenna and nephew Gabriel Oakes among its few visitors last year, emphasizes teaching.The objects in the Udvar-Hazy, above, and City Museum, below, may be like night and day, but Santa Fe's Museum of International Folk Art (left, with the late Alexander Girard, its benefactor) proves the importance of visual impact.