MAYBE IT'S the unpaved parking lot, or maybe it's the fishy smell from the Baltimore Harbor backshore. Anyway, the kids catch on real quick that this isn't just another Smithsonian tour.

The Baltimore Museum of Industry occupies part of a harborside cannery from which they used to send oysters off to the boys at war -- the Civil War -- and the building shows every year of its honest working life. Scores of the city's old-line manufacturers have contributed to the museum's growing collection of artifacts of the way we worked in the days when hardware meant nuts and bolts and software was something you slept in.

There's a printshop, a machine shop, a sweatshop and a whole lot of other neat stuff. Out back, lashed to the dock, is the old steam tug Baltimore, once the flagship and pride of the Baltimore Harbor Board. Rescued from the bottom of the Sassafrass River, she's being lovingly and laboriously resuscitated by volunteers.

That all of these wonderful old machines actually worked (most of them still do) and that real people worked them seems difficult for the modern child to comprehend. Your average young person today apparently believes that milk is made at the Safeway and that cars grow on trucks.

The kids on special or school tours don't leave the museum thinking like that, though, because hardly have they come through the door before they're issued time cards and put to work on an assembly line. In the space of an hour, participating in what at first seems only to be a simple game, they learn how bits and pieces pass through many hands to become finished products.

The youngsters also experience a little of what it's like to be in a work situation where one mistake, a moment's inattention or a display of individual initiative may send ripples down the line that wreck a whole production cycle. And some of the frustration of taking delivery of a new car only to discover that one of the wheels isn't round and that some clown put the frammis in backward.

Conceived by museum staffer Barbara Drazin, the assembly line produces cardboard vehicles modeled after the museum's 1914 Autocar chain-drive, solid-tired van, which spent half a century hauling stuff around town for Davidson Transport.

Some students are assigned to the work stations, where they punch out, stamp and assemble cardboard cutouts; others act as roving supervisors or quality-control inspectors. An observer who had served some time on a real auto assembly line was impressed by how quickly the "workers" came to resent the "bosses," just like it was down at the plant. And how workers who were falling behind soon developed a cavalier attitude about whether Tab A was properly inserted in Slot B, just like down at the plant.

"I find it very interesting that the younger children usually master this more quickly and do it better than the older ones," said staffer Denise Harper while watching a line manned by a bunch of parochial-school sixth-graders go to hell in a handbasket. "I had second-graders last time, and they turned out their cars like troupers." Harper did not speculate on the deeper meaning of this.

Charles, who was doing final inspections and finding it necessary to reject fully half of the vans, gave it as his opinion that it was all forelady Charlene's fault (names have been changed to protect the innocents). "It was going great before she butted in," he said. "She is a jerk."

"Do you think there's something wrong with a girl being in charge?" he was asked.

"No, girls are okay. But that Charlene, she is a jerk."

Afterward each kid got one of the vans to take home. Charlene got one of the good ones and Charles one of those bearing his own X. Life isn't fair. BALTIMORE MUSEUM OF INDUSTRY -- 1415 Key Highway, Baltimore (follow the Fort McHenry signs from the Inner Harbor until you find yourself on Key Highway). Open 11 to 5 Thursdays and Fridays, 10 to 5 Saturdays, noon to 5 Sundays; Mondays through Thursdays by appointment to groups of 10 or more. Admission $2 adults, $1 students and senior citizens, $6 families, children under six free. Materials fee for assembly-line sessions, $1 per person. 301/727-4808.