A typical Korean child's outfit is displayed among the artifacts from the rural village of Sam Jong Dong in an exhibit which opened to the public yesterday at the Museum of Natural History.

It consists of a polyester sweat suit and navy sneakers. What did you expect?

The show, called "A Korean Village in Transition," documents the rapid changes there since the Korean war. But the point about the sweat suit, shown near elaborately made silken costumers of traditional design, is not a simple one of Western influence arriving in the East.

The biggest reason that Korean children from an agricultural village dress like American children in urban centers is that both of them may be wearing clothes made in Korea, and it's a lot cheaper for a Korean parent to buy local products designed for export then to acquire hand-sewn silks.

Neverthless, the town never underwent violent change and has not rejected the traditional, said Dr. Eugene Knez, who was an information officer in war-time Korea when he first began to study Sam Jong Dong in his spare time, and is now a curator of Asian anthropology at the museum.

The place was "almost entirely traditional," he said, when "listening to artillery in the background" while he tried to do quick field work for his doctorate, in case the war should take a turn which would deny him access to Sam Jong Dong.

Now plastics have taken over.

As a foreigner, he regrets this, "but the villagers didn't ask me." For them, it's cheaper and more convenient, and the concession to esthetics is to splurge on the old things - such as the ceremonial costumes or lacquer-and-brass trunks - and to try to make the plastic objects look the way they used to.

The anachronisms creep in. A straw hat is delicately banded with a strip of movie film with the face of a popular actress.

But the chief charm of the exhibit, which will be here through mid-December and then travel to other museums, is the way in which the villagers have approached change. Instead of rejecting either past taste or present necessities, they have carefully evolved and modified.