Q. For the 60th time this summer, my 12-year-old says there is nothing to do. Here he is, living in the most exciting city in the world, and he's bored. He's had tennis lessons and swimming lessons and he still hangs around.

A. It takes more than food to feed a child. He needs enough independence to find out that adventures are everywhere, just waiting to be had. The child with enough adventures in his bank can draw on them to think of something new to do.

Lessons are all very well for competence, but without a follow-up, they don't mean much. Now that he knows the rudiments of tennis, how often do you challenge him to a game? Have you had him check out the swimming team at the recreation department? Nothing will improve his skill more and since there usually are a lot of teams, almost everyone can find a slot. We encourage this, not because the competition is important, but because the meets will give his life a sense of purpose.

By now a 12-year-old ought to feel so comfortable with the subway system and our big government buildings that he has his own gallery pass to the Capitol in his wallet. As long as they're on their own, he and a buddy will have a lot of fun watching congressmen carry on -- both on the floor and at one of the jazzier committee hearings, where the action makes much more sense. If nothing else, they can bop around the Hill offices to pick up state maps and information for school (and maple sugar and peanuts and whatever else is being dispensed in the congressional offices).

There is the trip to the Supreme Court, where arguments are heard on Mondays, Tuesdays and Wednesdays between October 1 and April 23, from 10 a.m. to noon and 1 to 3 p.m. And then an hour or so at the Superior Court so he can see how it all starts.

A Twelve is ready to spend a day on the Mall with his pals, going there by subway, eating lunch on the grass, keeping in touch by phone every few hours and being home by supper. In the meantime they have the joy of bing on their own in the big city -- to pop in and out of the free museums; to go up to the Monument for the best ride in the city -- no charge to children under 16 -- and the carousel in front of the castle, which only costs 35 cents.

You may say your child has done these things before, but there's a difference: Now he does them alone.

At this age he's also about old enough to be a go-pher somewhere -- so long as it's place where something obviously happens, and not, say, a law office.

We know one nifty boy who started helping out at a photography shop after school in exchange for using the darkroom, and a girl who shoveled out stables to get free horseback rides.

To work in campaign headquarters is pure glamor, especially if the candidate is winning, and a child will keep the faith long after the rest of us despair.

The Twelve who joins the Friends of the National Zoo can take part all year in the one-shot art-to-zoology classes and help write the bi-monthly Paw Prints, the newsletter for junior members.

Everything a child learns by experience is precious because it makes him want to learn more. That's where self-motivation comes from.