Chicago Public Schools is setting guidelines for a longer high school day for the 2012-13 year. CPS maintains that the district falls behind nationally in instructional hours. And that’s coupled with underperforming schools. Meanwhile, Chicago parents, students and the teachers union are all asking tough questions about what to do with 40 more minutes of school each day.

Here’s a typical schedule for one Chicago high schooler.

Selena Frandsen is a junior at Jones College Prep in the South Loop. On this particular Wednesday, Selena got out of school at 2:50 p.m. Then she had rehearsal for a student play. After that, it took Selena 45 minutes to get to home. At 6:30 she walked through the door and ate dinner. Now it’s about 7:30 and Selena is ready to face between two and three hours of homework.

She’s heard that CPS high schools are going to add 40 minutes or so to school each day. That makes her wary.

SELENA: I see some of the benefits to it but as of right now, as a high school student, you’re so sleep deprived, you’ve got so much work that you’ve got to do.

Selena’s mother, Miriam Cohen, is apprehensive, too.

COHEN: I don’t think it’s really necessary for high school because they already have a long day. And they’re tired. They’re tired just now. I can’t imagine another 45 minutes. It doesn’t seem like a whole time and yet I think it will … it’s just that much for stuff that’s expected of them and that much less time they can just be themselves.

CPS says it will let high schools decide what a longer day will look like. Jones is a rigorous, selective enrollment high school.

Teenagers have different demands from elementary school students, among other things, they have extracurricular activities and afterschool jobs. But the thing is … as CPS is adding class time to high schools, most people don’t know that, currently, different high schools handle their existing class time in radically different ways.

TEACHER: Before we go around, think about something that’s stressing you out.

Lindblom Math and Science Academy is in West Englewood. Here, a teacher leads a group of girls in a classroom in the high school’s health wing. It’s a colloquium called Girl Talk – a session to help teens who might be struggling academically or socially.

STUDENT: Cheerleading, grades and too much drama. I don’t do drama and it’s drama coming to my life and I need to delete it quick, fast and a hurry.

On Wednesdays Lindlbom students are in school for a half day. They have had options to participate in various kinds of colloquia – from help with Chinese to protecting animal rights to running a farmers market in their West Englewood neighborhood.

MATHER: The parents were the most vociferous about needing to keep the colloquium day, that restructured day.

Alan Mather is the principal of Lindblom.

MATHER: What they articulated was that this school is so intense academically, the students need a break from what happens on the other four days. And it’s not a break where you’re just hanging out but you’re getting support in other classes where you may be struggling.

Mathew says students are in school longer on those other four days to make up for seminar days. And next year, they’ll have an even longer school day.

One question that lingers is: What can a top-performing high school get out of a longer day? Lindblom already exceeds state standards. In fact, it’s one of the top high schools in Chicago.

MATHER: High-achieving kids work hard and there’s nothing wrong with having them sit with their teacher and get additional support.

Mather hopes to use some of the extra class time to weave in community service for the students.

The Chicago Teachers Union says the push for a longer school day is just a political demand, a way to show some muscle before contract negotiations. Union officials say a broad curriculum is what’s most important – not length of day. And CTU official Jackson Potter has concerns about gaps in what struggling schools receive versus high achieving ones. He’s a former high school teacher.

POTTER: What we don’t want is for the mighty and powerful having their children in this city getting art, music, recess, physical education, world languages and the rest of the students getting drill and kill. Reading and math, reading and math and reading and math — without the broader elements that make life worth living.

Chicago’s debate about a longer day is tinged with the issue of class.

Some parents at high-performing schools don’t want their children to have a longer school day. At the top-tier North Side College Prep, parents have petitioned CPS to keep their schedule of colloquia, and say their children already have a rigorous academic environment. Parents say a longer day would pump up kids’ stress levels.

That drill and kill the teachers union refers to might be the case at Robeson High School. It’s an underperforming high school with low-income students in Chicago’s Englewood neighborhood.

Robeson is just three miles away from the stellar high school you heard about earlier, Lindblom.

CROWD: applause

Robeson students are crammed into an auditorium for a talent show.

Upstairs, away from the performances, Principal Gerald Morrow’s office is known as ‘the cave.’ It’s on the second floor in a converted classroom, in close proximity of students.

Robeson students typically come in below grade level and need help with writing. Principal Morrow says he’s not worried about an imbalance in what different schools may get in their longer day. He says teachers want more resources.

MORROW: They’re going in the direction of wow, we can have the kids an extra 30-40 minutes to give them what they need because they already push we need a reading lab, we need a writing lab. I might not be able to give you extra room but I can give you extra time.

CPS CEO Jean-Claude Brizard has said a longer school day would reduce the need for tutoring or give students extra help within the day.

There’s been mixed research as to whether a longer school day improves a student’s academics, but there are educational groups willing to say there is a link. The Boston-based National Center on Time & Learning is dedicated to expanding learning time in schools.

Jennifer Davis is the co-founder and president. Davis says tailoring to an individual student’s need is the best way to maximize a longer day — whether that includes labs or art.

DAVIS: A longer day provides opportunities for a deeper opportunity to really experience the curriculum to participate in science experiments, for example, to have exposure to additional classes in the content areas where they’re not strong.

Incidentally, the school where Chicago Mayor Rahm Emanuel sends his own children has implemented a new high school schedule. The University of Chicago Laboratory High School has recently extended its instructional time for students. But the private school pulled that off by reducing unscheduled time for students.

It did not lengthen its school day.