What is Mexico like? Four-year-old visitors to the Mexican exhibit at Capital Children's Museum have some ideas: "They dance around the hat." "Cactus." "There's cowboys with guns."

The mexican exhibit that will be there through the year teaches them more. They learn by doing. After an orientation film - Mexico, land of enchantment, land where the Six Million Dollar Man is Hombre Nuclear - the kids are exhorted to pretend to be Mexicans in the museum, and do what they saw in the movie.

Downstairs is a village with dirt-floor huts, a general store, a central square and a farm-yard where goats live. The children can make tortillas, buy and sell in the Miscelanea, paint with yarn, cut paper sculpture, play house and weave.

Upstairs, there's a three-part exhibit of Mexican woodcarving, embroidery and papier-mache, with films showing the artists at work. Called "Artesanos Mexicanos," the show is on loan through May from the Craft and Folk Art Museum in Los Angeles.

One of the rooms is full of papier mache figures fashioned by Pedro Linares. In a lifesize mariachi band, half a dozen skeletons leer from behind their instruments. In another display, red devils take fantastic shapes.

The sign beside the devils and demons quotes the artist, in Spanish and English: "The figures are, well, very ugly you know - quite horrifying, right? Ah, but at the same time they are very beautiful." The kids stare at them thoughtfully, and the guide explains the skeletons are paraded during a yearly "Day of the Dead," when people remember relatives who've died.

Downstairs in the village it's time to work, and the kids, from Beverly Hills Co-Op nursery in Alexandria, are turned loose to find an occupation.

In a log cabin, some perch on tiny chairs and make tortillas from cornmeal, lime and water. Doceat Linda Quarles explains that the corn is removed from the cob, soaked overnight, dried, then ground into cornmeal.

Ashley and Drew take turns removing the hardened yellow kernels from the cob. "What are we going to make?" Ashley asks. "Popcorn," says Drew. Other kids are turning the handle of the grinder the wrong way, and the corn comes out whole. "What we need here is a Cuisinart," Drew's mother observes.

The tortillas take 10 minutes to cook over a gas burner, and the kids don't wait around, but go outside to try on sombreros and work on crafts. A chirping chorus of four-year-olds flits in and out of the little hut. "Is my tortillo ready yet?" Most of them know what to do with the little patty once it's cooked, except for a boy who stands by the grinder: "Where do I put it? In here?"

"Some of the kids like the tortillas," says Quarles. Others don't."We find the tortillas in the corners, or stuck up in the little tree outside, or in the goatpen. The goatsdon't like tortillas."

Around the corner in "Miscelanea," the general store, the kids measure out and weigh beans, nibble Fritos and pretend to buy cans and cans of jalapeno peppers.

In comes an hombre named George, dressed in a sombrero and plaid shirt. "Look! Look!" he calls out excitedly. With two little hands, he spreads a slip of pink tissue paper with shredded edges. He's asked what it is. "I don't know," says George. Then he brightens. "When I get home maybe my mother will tell me."

In the square, Jenny Champey is showing the kids how to make yarn paintings. They aren't painting yarn, they are painting with yarn, embedding it in hot wax to make a medallion from a coffee cup lid. Champey explains that real yarn painters in Mexico do their best work after peyote ceremonies. "They hallucinate, and then take a lot of time creating the symbolism they see in yarn."

Two little girls have set up housekeeping in acane hut beside the goatpen.They make "Mexican tea" and apologize to a visitor for the dirt floor.

Outside in the "farmyard," at the well, a boy gives a Spiderman doll he brought in his pocket many rides down in the bucket.

There are three tortillas in the goatpen.

A QUICK TRIP TO MEXICO

This Saturday, Capital Children's Museum is holding a "first annual" parade through Northeast Washington, starting at 10:30 at Lovejoy Elementary School, 12th and D Streets NE, where the museum used to live, and ending at its new home, 800 Third Street NE. The Army band, a local school band, mimes and animals will march into the courtyard carrying pinatas and lollipops. This is one day kids can go to the museum free. It's open from 1 to 4.

Usual hours are 2:30 to 4:30 Tuesday through Friday (mornings reserved for group tours), and 11 to 4 Saturday. Children pay 50 cents, adults $1.50. (Call MET-KIDS.) CAPTION: Picture, MAKING TORTILLAS AT THE CHILDREN'S MUSEUM, PERHAPS FOR THE GOATS. By Joel Richardson.