Okay, shuffle the kids out to the school bus, shut the door and let's talk about school. Let's talk about more school.

Over the summer, while the classrooms were empty, the papers were full of education. Many of us, the adults, spent our summer vacation diagnosing schools. We identified the most communicable disease as mediocrity.

Now it appears that the favorite national prescription is more classroom time. If kids need more education, we may be giving them a bigger dose of school.

In the spring, the National Commission on Excellence recommended that we increase the school year from an average of 180 days to 200 or 220 days, and increase the school day from five or six to seven hours. This fall, two school districts in North Carolina added 20 days to their year, and many high-school students in Florida added a seventh period to their day to fulfill new graduation requirements.

In California, the longer days and hours voted by the state legislature were only tabled for lack of funding. In New York, the Board of Regents has proposed adding time, and education officials in Illinois and Ohio are likely to follow suit.

By winter this particular cure may be the best-seller in over- the-counter education business. It simply appeals to a varied and mass market of adults who range from punitive to positive.

There are, for example, the Sonyniks among us, who think we should do as the Japanese do. If Japanese children attend school for 240 days and have 25 percent more instruction time than American children, then ours should too. They blame our economic problems on the education of children rather than the management of business and government.

Then there are others of us who simply want kids kept off the streets or out of the adult world for longer periods. Longer school hours are always popular in rough economic times. It took a Depression to popularize the idea of universal high school. The age of compulsory schooling was raised deliberately in the 1930s to remove teen-agers from the job market. Lengthening school days today would effectively remove a mass of part- time teen-age workers from the job market.

In the same economic climate, more and more two-parent working families, and single-parent families, worry about supervision of their school-age children. Breathes there a working parent so secure that he or she has never thought: "It's 4 o'clock, do you know where your children are?"

One of the dirty little secrets about the attraction of private schools is that they keep the children later. For each hour added to school, you may subtract one hour of parental anxiety.

I am not suggesting that these are evil motives. There's nothing malevolent about wanting to keep children supervised, off the streets, away from the TV sets, to keep their days structured. Idle hands, etc. For many reasons, a longer school day and year would be a boon. But most of these are, it should be admitted, social reasons, not educational reasons.

Americans have always looked to schools to solve social problems, problems of immigration, industrialism, racism. It's understandable that many of us support this new cure to relieve the latest symptoms of a changing economy and a changing family life.

But if we are also talking about excellence, talking about learning, there is no guarantee that more school begets more education. Back in the 1940s only 40 of every 100 young people graduated from high school; by 1980, 75 of us finished high school and we remain discontented with the results.

The problems of teaching and learning are still the basics, whether the days are five hours long or seven, whether the year is 180 days long or 220. Another hour or week in a school that incarcerates teachers and students in the same dreary environment is an extended sentence. The same time in a learning environment is a bonus. It's easy to add hours, the trick is, as always, to fulfill them.

After hearing the educator Horace Mann speak in 1839, Emerson wrote in his journal, "We are shut in schools . . . for ten or fifteen years and come out at last with a bellyful of words and do not know a thing."

Let the kids back in and read that one to them.