Kids can roll in the dough this Saturday at the Art Barn in Rock Creek Park. Experts will be on hand to show you how to make play dough from flour and then how to sculpt and paint it. The supplies, instruction and recipes are provided free of charge, and if you show up at Pierce Mill an hour before, you can see Ted the Miller grinding the flour used to make the play dough.

Also notable this weekend is Anacostia's "Second Annual Music for the Inner City" program on Saturday and Sunday. Eight musicians will be on hand at the Stanton Community Center and Alan Chapel Outreach House in Washington to perform works from Bach to Haydn and demonstrate how their instruments work. The program runs through September 2.

The following activities are free unless otherwise noted.

NATIONAL ZOO -- Open daily; gates open from 8 to 8; animal buildings, 9 to 6; panda feedings, 11 and 3; elephant training demonstrations, 2; Sea lion training demonstrations, 2, 3001 Connecticut Ave. NW (Rock Creek Park), on the Metro Red Line. Family learning centers Zoolab and Birdlab open Friday through Sunday, noon to 3; Herplab open Wednesday through Sunday, noon to 3. 673-4717.

OXON HILL FARM -- Open daily, 8:30 to 5, Oxon Hill Road (take Beltway exit 3A, turn right on Oxon Hill Road). Saturday and Sunday, 1 to 3, "Horse and Wagon Rides." Come early and see the team harnessed. Saturday, 12:30 to 2, "Butter Churning." Help farmers churn fresh cream; bring your own biscuit for buttering. Saturday and Sunday, 10 to 3, "Silage." Watch corn get chopped and blown into the silo for storage. 839-1177.

NATIONAL AQUARIUM -- Open daily, 9 to 5, Department of Commerce, 14th and Constitution Avenue NW. The sharks are fed Monday, Wednesday and Saturday at 2; weekday features are a touch-tank, mini- theater and a thousand types of marine life. School groups should schedule in advance. Adults $1; children 50 cents. 377-2825.

CEDAR HILL -- Open daily, 9 to 4, 1411 W St. SE, Anacostia. Cedar Hill, Frederick Douglass' home, recalls his work with films, interpretive exhibits and a house tour. 426- 5961 or 426-5962 or 426-5963.

USS BARRY -- Open daily, 10 to 5, Washington Navy Yard, Ninth and M streets SE. The Navy destroyer's weather deck is open for public viewing and self-guided tours. 433-3377.

CHILDREN'S MUSEUM -- Monday through Saturday, 10 to 4, Sunday 1 to 4, Rose Hill Children's Museum just north of Frederick, Maryland. Take U.S. 15 north to Exit 8 to Motter Avenue; follow Motter to left onto 14th Street and left onto North Market Street, follow signs to Rose Hill. Costumed tour guides will conduct tours of the 1790 mansion. Hands-on exhibits include a loom, antique toys and spinning wheel. Adults $1; under 17, free. 301/694-1646.

CAPITAL CHILDREN'S MUSEUM -- Daily, 10 to 5, 800 Third St. NE. Friday, 10:30; Saturday, 11, "Puppets on Parade." A variety show of colorful hand, rod and mouth puppets who perform musical numbers. Museum admission, $2; special performances an additional $2. 543-8600.

DOLL'S HOUSE AND TOY MUSEUM -- Tuesday through Saturday, 10 to 5; Sunday, noon to 5, 5236 44th St. NW. A collection of antique dollhouses, dolls, toys, games and an exhibit of antique cat games and toys. Adults $2; under 14, $1; group rates available. 244- 0024.

NATIONAL COLONIAL FARM -- Tuesday through Sunday, 10 to 5, 3400 Bryan Point Rd., Accokeek. Saturday, 1 to 4, "14th Annual Corn Harvest Festival." Colonial craftspeople demonstrate and sell their wares; fresh corn shucked and cooked in huge iron kettles and sold for a quarter an ear. Adults $1; children under 12, free. 301/283-2113.

CLOISTERS CHILDREN'S MUSEUM -- Wednesday through Friday, 10 to 4:30; Saturday, 12 to 4, 10440 Falls Rd., Brooklandville, Maryland, "Indian Summer Celebration." Hunt bear and porcupine hidden along a nature trail, dance around a totem pole and see an extensive Kachina doll exhibit. Saturday, museum hours, "Indian Crafts": make tepees, sandpaintings and decorate indian headbands. Saturday, museum hours, make a wood sculpture with glue and toothpicks. $2 donation requested from adults; group tours available. 301/823-2551.

RAILROAD STATION MUSEUM -- Wednesday through Saturday, 11 to 4; Sunday, noon to 5, Main Street and Maryland Avenue, Ellicott City. The renovated station has a diorama of the trip of Tom Thumb (an early 19th-century train) from Baltimore to Ellicott City. There are also sight and sound shows, model train exhibits and tours of the museum. Adults $1.25; under 13, 75 cents. 301/461-1944.

COLONIAL FARM -- Wednesday through Sunday, 10 to 4:30, Claude Moore Colonial Farm at Turkey Run, 6310 Old Georgetown Pike, McLean. Take a self-guided tour of farm life for a low-income family in Colonial Virginia. Ongoing demonstrations of agricultural and domestic chores, such as spinning and candlemaking, round out this history lesson. Adults $1; children under 12, 50 cents. 703/442-7557.

WOLF TRAP -- Friday, 10 to 1, Wolf Trap Performing Arts Center, 1551 Trap Road, Vienna, Va. "Theater in the Woods." Contemporary dance, American folk music and children's theater. Programs free, but call for reservations and schedule. 255-1827.

WATCH THE BIRDY -- Friday, 8 to 9 p.m., Amphitheater, Burke Lake Park, 7315 Ox Rd., Fairfax Station, Va. (take I-66 west to Rte. 123 south, which becomes Ox Road), "Feet and Beaks." Join a naturalist for a discussion about how birds have adapted to their environment. $3.50 park entrance fee for non-county residents. 451-9588.

CHILDREN'S RADIO THEATER -- Saturday, 8 a.m., WPFW 89.3 FM. "The Sky Is Falling Revue." When Henny Penny gets hit on the head, she decides to pursue a career as a recording star. Lsteners can participate in a call-in following each program by calling 783- 3104.

BATTING PRACTICE -- Saturday, 10 to 3; Sunday, 1:30 to 4:30; Tuesday and Thursday, 3 to 7:30, Tucker Road Community Park, 1771 Tucker Rd., Fort Washington, Md. Batting cage and automatic pitching machine; bats, balls and helmets provided. $1 for 20 balls; team reservations. 301/248-4404.

CLOWNING AROUND -- Saturday, 11 to noon, Meeting Room, Downstairs, Burke Branch, Alexandria Library, 4701 Seminary Rd., Alexandria. The Just Clowning Around Troupe will be on hand to turn up the corners of your mouth. Call for reservations at 838- 4598.

SWAMP ROMP -- Saturday, 11, Ramsay Nature Center, 5700 Sanger Ave., Alexandria, "Romp in the Swamp." Billy B sings and dances to teach kids the rock and roll of photosynthesis. 838-4829.

TROLLEY MUSEUM -- Saturday and Sunday, noon to 5, Northwest Branch Regional Park, Bonifant Road between Layhill Road and New Hampshire Avenue, north of Wheaton. Trolley rides: $1 adults; under 18, 75 cents; under two, free. 384-9797.

ORIENTEERING -- Saturday, 1, Nature Center, Prince William Forest Park, Rte. 619 near Quantico (from I-95, take Exit 50-B, Rte. 619 west; park entrance less than a mile on the right). A ranger shows you how to use a map and compass to find your way through the woods; equipment on hand for those who want to try it themselves. 703/221-2104.

CHILDREN'S PLANETARIUM -- Saturday and Sunday, 1 and 4, Rock Creek Nature Center, 5200 Glover Rd. NW. First show for children four to seven (must be accompanied by an adult); second show for ages seven and up. No latecomers are admitted. 426-6829.

ADVENTURE THEATER -- Saturday and Sunday, 1:30 and 3:30, Adventure Theater, Glen Echo Park, Glen Echo. "Toby Tyler," the story of a young boy who runs off to check out life under the big top. $3, group rates available. 320-5331 weekdays and performance days from 10 to 2.

MONSTER MASH -- Saturday and Sunday, 2, Long Branch Nature Center, 625 S. Carlin Springs Rd., Arlington, "Monsters: Mysteries or Myths." A 40-minute film about Big Foot, the Loch Ness Monster and the Abominable Snowman. 845-7640.

ROLLING IN DOUGH -- Saturday, 2 to 4, The Art Barn Gallery, 2401 Tilden St. NW, "Fun Day." Learn how to make your own play dough, mold and paint it. Supplies and instruction provided. At 1, you can watch actual grinding of the flour at the adjacent Pierce Mill. 426-6719.

MUSIC FOR THE INNER CITY -- Saturday, 5, The Stanton Community Center, 3234 15th Place SE; Sunday, 5, The Alan Chapel Outreach House, 2443 Ainger Place SE, "Second Annual Music for the Inner City Program." The first two of eight summer concerts designed to introduce children to classical music and the instruments themselves; eight musicians will be on hand each day to perform and answer questions from the audience. For directions and more information, call 699-5440 or 699-0440.