The Lego Approach to Learning. EDUCATION: A TOY AS TEACHER. Elementary students create and solve problems using plastic building bricks

TWENTY years ago Seymour Papert's colleagues thought he was a little bonkers. What else could be thought about someone who told stories about a time not far away when most American schools would have computers - for heaven's sake - that children could learn and play on? Save it for science fiction, please.

But Dr. Papert was right. Today one third of all elementary schools use the creative writing software he developed at the Massachusetts Institute of Technology (MIT).

And now the bearded MIT scientist is again a step ahead.

Papert has developed a new hands-on form of constructive learning in which children not only design and build mechanical toys and models, but they also design the computer software needed to operate them.

This has come at a critical juncture in education judging by four major reports released in the United States during the past two months detailing the lack of good math and science teaching and learning in public schools.

The new effort, already in a thousand schools across the country, stresses creative math and science problem-solving by doing.

The basic tool of Papert's program is the humble Lego toy - the multi-colored plastic building bricks which are already found in three quarters of American households with children.

Using a special kit consisting of Legos, tiny motors, sensors, and durable computer interface hardware, children have made model Ferris wheels, conveyor belts, toy cars that go when the light turns green, pop-up toasters, a miniature chocolate factory, and an alarm-clock bed that pushes the sleeper off at a designated time.

Students learn about gears and levers, the problems of friction, acceleration, and design stress. They also set up complex mathematical equations - all while ``playing.''

Last year, fifth-grader Michael Satut at the Hennigan School in Jamaica Plain, Mass., helped build a bobsled and track. The sled's speed can be measured with a sensor to within one-hundredth of a second.

``I was basically the programmer,'' Michael says, while connecting a wire clip from the track to the computer interface box, ``but I did trouble-shoot when we moved from a flat track to an incline.''

After Michael and his group came up with the bobsled idea, they drew a rough sketch of it. Then they broke into teams. One built the bobsled. The other programmed the computer with instructions, including an equation using seconds in an hour and feet in a mile to translate the sensor's information into a set time (between 1.3 and 1.7 seconds on most runs).

``For a while we had the multiplication and division signs mixed up, and we got bad readings - but we figured that out,'' Michael says matter-of-factly.

``Children make both simple and complex models,'' says Hennigan fourth-grade teacher Gilda Keefe. ``But what I like to see is the amount of cooperative learning going on among children. Also the fact that rather than just use software, they design it.''

``When you watch the kids work in class there is all this noise, all these ideas and experiments going on,'' Papert says.

For years he has been convinced that children learn most when they try to reach beyond themselves and, through trial and error, create things. Love more than duty creates a desire to learn, he adds.

A number of educators are impressed with how the program, LegoTCLogo, provides practical applications of science and math principles. They feel this is needed at a time when American competitiveness in design and manufacturing is being challenged by Japan and West Germany. Meanwhile, student interest and ability in science are declining. (Fewer than 10 percent of all students take physics; the US ranked 11th in chemistry and 9th in physics in a recent 17-country survey of high school science achievement.) `FROM the start, the idea was to break down the schism between theory and practice, science and engineering,'' Papert says.

Further, ``It's not just `hands-on,' which everyone believes in anyway,'' says Michael Resnick, one of Papert's colleagues at MIT's Media Laboratory, ``but it's kids designing their own problems, rather than just being given them.''

Lego bricks can create an almost unlimited number of shapes. Two same-colored bricks with eight grips can be combined 24 ways; six bricks can be combined 103 million ways. LegoTCLogo runs on either Apple or IBM computers. The kit costs $500.

Some educators do have reservations. Education policy expert Joseph Nathan of the University of Minnesota's Humphrey Center , says the program is far better than worksheets and ``mindless, boring exercises.''

But after seeing it used in the Minneapolis schools, he warns against the zeal among parents and administrators who believe that new technology will always make their children better at solving problems.