As soon as Ida Prosky's kids learned to walk, she started dragging them around to Washington's museums and other local points of cultural interest. Now, as field education director of Capitol Hill Day School, Prosky takes other people's kids - two or three little yellow busloads of them a day - on trips designed to supplement what they're learning in the classroom. Since every class in the small private school goes on at least one field trip a week, Prosky is constantly dreaming up new educational experiences - some of which are discarded after the first foray while others are repeated year after year.

"My worst debacle was measuring the shadow of the Washington Monument," Prosky recalls. "It sounded like a good idea, but the shadow kept moving faster than we could measure it."

One of Prosky's repeated successes takes place just down the Mall at the Lincoln Memorial. To mark Lincoln's birthday, Prosky bakes a cake and throws a party on the steps of the memorial for the school's younger kids.

"We light a candle and sing 'Happy Birthday,'" says Prosky. "The first year we felt a little sheepish, but then parents heard about it and joined us the next year and it became an event . . . It's easy to explain even to small children that Lincoln made it against the law for one person to own another person."

Prosky also felt sheepish when the U.S. Capitol Police asked to see a permit for the fourth grade's planet hike.

"The fourth grade was studying the solar system, so to get an idea of relative distance and scale we used the Capitol as the sun. We figured out a ratio of feet to light years, and each kid walked out a certain distance, carrying a replica of his or her planet," she recalls.

"The kid who was representing Pluto was way out around Lincoln Park somewhere. The replica of Mercury was so small that a tourist stepped on it, then apologized profusely - in German."

At about that time the guards started asking about a parade permit, but the mission had already been accomplished.

To teach mini-economics, Prosky takes kids on comparative shopping expeditions.

"We make out a list and then one group goes to the Safeway and another to the Eastern Market and buys the same things," says Prosky. "They usually find that while the Safeway is cheaper, the quality and service are better at the Eastern Market. Then we make vegetable soup."

Prosky also makes frequent use of the city's art galleries, but not always to teach art appreciation.

"The Hirschorn has a room-size collage of the Russian Revolution by Larry Rivers," she says. "There are real guns in it, and factory pipes, as well as portraits of he czar and the revolutionaries. There are maps and pictures of people lying in the street. In this room, you can explain to kids the reason for the Russian Revolution. Sixth graders don't leave with a complete understanding ofthe Russian Revolution, but at least they get a feeling for what it was about."

Here are some places where Prosky likes to take kids, and where you can take your kids:

CIVIL WAR FORTS: Some 50 forts ringed the capital during the conflict, and many are still there. The only one that saw action was Fort Stevens (Piney Branch Road and Quackenbos Street NW), site of the Battle of the Suburbs. Confederate General Jubal Early's troops met Union forces at Fort Stevens in a battle witnesses by President Lincoln, who was warned by Lt. Col. Oliver Wendell Holmes to "Get down, ou fool!"

Prosky usually brings along some props, has the kids restage the battle and then takes them to the fort's cemetery.

The museum at another Civil War installation, Fort Ward (4301 West Braddock Road, Alexandria), has a large map showing all of the forts built to protect Washington.

THE MATISSE TOWER in the East Building of the National Gallery: Prosky likes to take first graders there to talk about forms, color and positive and negative space while viewing the largest Matisse cutouts. She shows the kids a split-leaf philodendron first, and they see the leaf motif repeated in the cutouts.

TURKEY RUN FARM Old Georgetown Pike, McLean: "Because the people there don't act like tour guides," says Prosky. "They think just as though they were living in the colonial period."

KENILWORTH AQUATIC GARDENS Anacostia Avenue and Douglas Street NE: "Go to see the six-foot Chinese lotuses in summer and the muskrats, ducks, crayfish, turtles, toads and snakes all year round," Prosky suggests.

THUNDERBIRD ARCHEOLOGICAL PARK on Route 340 seven miles south of Front Royal: "It's the oldest pre-history site in North America," says Prosky, "but it's not like going to a hole in the ground. You can go up a hill where giant mammoths used to roam, and slide down the hill on slippery jasper rocks to the place where Indians dried fish. The jasper rocks were used to make stone tools, and someone will show you how the Indians made them."

THE RENWICK GALLERY: "To see the miniature teepees each Indian tribe made at the Smithsonian's request in 1910."

ARLINGTON HOUSE, the Lee Mansion on the grounds of Arlington Cemetery: "This house helps kids make a connection between colonial times and the Civil War, because it was built by an adopted grandson of Washington whose daughter married Robert E. Lee." Try to get in on one of the super colonial tours where they take kids to the attic to make toothpaste out of burnt toast.

CEMETERIES: "They're one of my favorite places to take kids," says Prosky. "Rock Creek Cemetery dates from 1700s and has some excellent pieces of art in it - the Adams Memorial, the Seven Ages of Man, Mary Magdalene. I take the younger kids here to go grave-rubblings. It's a very pleasant place, and we don't spend time talking about dead people. Before we go we melt crayons in muffin tins. When the wax cools you have a nice flat surface to rub with. One kid holds the paper while another rubs. Even if the paper slips, you get super effects."

Prosky also takes the third grade to cemeteries to talk about what weather does to various types of stone. When the fourth grade is studying the Civil War, she takes them to Congressional Cemetery, where there's a momument to 23 young women munition workers killed when the Washington Arsenal blew up.