The traditional American school year begins in late August or early September. It ends in May or June, followed by summer vacation.

Why such a long break? Because long ago, young people had to help their families harvest the summer crops. At least this is what people today may think.

The reason has more to it. A recent report from an education policy center at Indiana University explored the historical roots of the traditional school calendar.

In the early days of the United States, children were not required by law to attend school. School calendars depended on local needs.

Students in rural areas went to school for no more than six months of the year -- half in the summer, half in the winter. They worked on family farms during the other months.

City schools were often open much longer, some for eleven months of the year. Parents were happy to have a place for their children to go while the parents worked.

National leaders took a fresh look at schools after the Civil War, in the eighteen sixties. They saw a free public education as a way to help support a strong democracy and prepare workers for new industries. Immigration was increasing and so was the student population.

More and more people saw the need for a system of required education. But they had different ideas for the calendar.

Many city schools wanted a shorter year and a longer summer break. The schools were often crowded. There was no modern air conditioning and air pollution from factories was a problem.

Hot days would make it difficult to learn. A long summer break would also give teachers time for other jobs to add to their low pay.

Many rural educators, however, pushed for a longer school year. They thought it would keep children safe from industrial dangers at a time when there were few child-labor laws. They also thought it would lead to a better prepared workforce.

So the traditional school calendar was a compromise, with roots that now go back about a century and a half. The average school year used to be one hundred seventy days. Times have not changed much. Today the common average is one hundred eighty days.

But some experts think the traditional school calendar needs to change because the needs of the nation have changed. This thinking has led some schools to keep students in class longer. More on that next week.