This month millions of American kids flee the tyranny of the classroom bell for lifeguard stands, grandparents' homes and sleepaway camps. But summer vacation hasn't always been a birthright of U.S. schoolchildren. In the decades before the Civil War, schools operated on one of two calendars, neither of which included a summer hiatus. Rural schooling was divided into summer and winter terms, leaving kids free to pitch in with the spring planting and fall harvest seasons. Urban students, meanwhile, regularly endured as many as 48 weeks of study a year, with one break per quarter. (Since education was not compulsory, attendance was often sparse; in Detroit in 1843, for example, only 30% of enrolled students attended year-round.)
In the 1840s, however, educational reformers like Horace Mann moved to merge the two calendars out of concern that rural schooling was insufficient and--invoking then current medical theory--that overstimulating young minds could lead to nervous disorders or insanity. Summer emerged as the obvious time for a break: it offered a respite for teachers, meshed with the agrarian calendar and alleviated physicians' concerns that packing students into sweltering classrooms would promote the spread of disease.
But the modern U.S. school year, which averages 180 days, has its critics too. Some experts say its languorous summer break, which took hold in the early 20th century, is one of the reasons math skills and graduation rates of U.S. high schoolers ranked well below average in two international-education reports issued in 2007. Others insist that with children under mounting pressure to devote their downtime to internships or study, there's still room for an institution that sanctifies the lazy days of childhood.