The traditional American school year is gearing up. Whether classes start this month, or not until the first week of September, displays of pencils, notebooks and backpacks are appearing in stores, families are heading home from vacations, and most kids are starting to think about the transition from nearly three months of summer break to more than eight months of homework and exams. Most kids, but not all.

It is a glorious Monday at the Santa Monica Pier in Southern California. The perfect day for a ride on the Ferris wheel, or the roller coaster. Below the steel track of the coaster, parents beam as their kids tilt-a-whirl or smack each other around in bumper cars. Little kids toddle by with their dripping ice cream cones. It just doesn't get any better than this. Or does it?

Less than an hour, but a world away, 20 seven-year-olds positively bubble as they chirp along with the poem of the day. It is "Polka Dot Pajamas." This is a third grade classroom at Cahuenga Elementary School, in the Korea-town section of Los Angeles.

"The district is facing a tremendous problem," said Lloyd Houske, Cahuenga's principal. "Los Angeles is really sort of an international port of entry and the communities in the inner city are becoming crowded and so at my school we bus away 1900 children every day because of lack of space. And so I send to about 15 other different schools. The school itself is not overcrowded, it's the neighborhood that's overcrowded."

This school was built to hold 900 kids, tops, during the standard August through May school year. But it can educate about 1300 students with year-round schooling. Over a 12-month period, students attend classes in three shifts, or "tracks."

Teacher Mario Loeza said, "I think it's better for the teachers than for the kids, because just when you need a break, there it is."

He and his kids just started school, on the "C-track" and will get all of November, December, May and June off. Mr. Loeza has been on this "four months on, two months off-track" schedule for five years. He says it took a while to get used to, coming from a traditional background, but he now loves it, especially being on vacation when the rest of the world is working. Although he admits there are some drawbacks, for teachers and students.

"The kids get two months off," he said, "two months to forget everything and then they're back. A lot of times when we come back on track we spend the first two weeks kind of reviewing the past four months, because they've been out of school two months. Every time we go back on track it's almost like starting the year over again because they've had a large break in between their schooling."

There is also the problem of state standardized tests, which are given in April. For Mr. Loeza's students, that's the last month of their track. But kids on another track come back to school after two months off and have about a week to prepare for the test.

Despite the challenges, tens of thousands of Los Angeles county students attend school this way. This year, 224 out of 791 schools, from kindergarten right up through high school, are running on either a three or four-track schedule. It may seem odd to those used to the tradition school year, but third grader Johnny Contreras does not seem to care.

Aaron Schachter: "Is it weird being in school when your friends are on vacation? Like now, it's July, it's summertime."

Johnny Contreras: "I know, but actually, I don't really think of that all the time 'cause, school's very fun if you get to learn to do stuff with the teacher and then school gets a lot of fun so sometimes I don't even think of that. It doesn't matter to me."

While year-round schooling is by no means a new phenomenon, it is a growing one in the United States, as once-sparsely populated areas become more and more dense: places like Clark County, Nevada, and Denver and Douglas Counties in Colorado, not to mention a host of major West and East Coast cities.

Johnny Contreras may not mind spending a summer day in school, but his schedule is upsetting to many according to Mike Griffith, a Policy Analyst with the Education Commission of the States. He said, "There's a lot of scheduling difficulties, because if there are multiple kids within one family, you want to make sure that their breaks all happen at the same time. Parents become a little upset if each of their five children has a different time that they're off, out of school. The other difficulty is the tourist community. They're used to the summer break as being a large time for tourists. Especially places in the midwest or east that have limited vacation time. Whereas if you have an amusement park or a water park, it can only be open 4 months of the year and you'd like all kids to be able to do that at once. It sounds like a small problem, but I think it's a little larger than a lot of communities had realized."

Mr. Griffith says year-round schooling is well worth the trouble. He points to studies that show kids actually regress intellectually during the summer break - and a bottom line that shows keeping school buildings open all year makes fiscal sense.

"Cost benefit wise, it is a definite benefit," he continued. "School buildings are very expensive. A new high school costs about $20 million. If you can rotate students and prevent yourselves from having to build that extra building, right there you've saved $20 million that you can use for other programs."

Mr. Griffith says it may be initially difficult to work out teacher contracts for year-round schooling, but the examples provided by schools now operating under this calendar prove it can be done.