SAN FRANCISCO — At 8:30 a.m. every weekday, Sadie Barnett’s 9-year-old daughter opens her laptop and logs on to Zoom to start the school day. For the next 6½ hours, she’s not allowed to turn off the computer’s camera except for a midday lunch break. Along with the 94 other children on the call, she isn’t allowed to eat or drink on camera, wear pajamas or lounge or lie down.

In her first full week of fourth grade, she has already cried twice because her head hurt from squinting at the screen.

“It’s painful to watch,” said Barnett, who lives in Pennsylvania.

Headaches, anxiety and exhaustion caused by never-ending video meetings are no longer exclusively for adults trying to work from home during the pandemic. Some schools have started the fall semester with remote-learning setups that mimic what a full day of school was like before the coronavirus crisis.

In the spring, when much of the world still naively believed things could return to normal in a couple of months, experts and parents waved away guilt about screen time.

But things are different this fall. As more schools have organized full-time classes online in real time, we’re seeing kids hit their limits with certain kinds of screen time. Many schools stopped grading students or even taking attendance in the chaos of last spring, but those formalities are back. Kids have to log on and often be seen on a camera to be counted as present. There are new rules about what to wear, where they’re sitting and how they can move their body. And cameras and microphones are, for many students, not optional.

Experts say not all screen time is the same, and blanket rules over how many hours to allow aren’t effective when you add in remote school. Families can feel powerless to control how much screen time schools are tacking on to their children’s days, especially when they need some of it to get their own work done.

It’s still early in the school year, and everyone involved in distance learning is figuring out what works and what doesn’t. Reaching out to administrators and teachers early on could shape what the future of online learning during a pandemic looks like. And talking to children to see how they’re feeling is important, too.

Live or not, screens are at the center of almost all remote learning setups. As with everything during the pandemic, the approaches could change.

“I think where we screwed up maybe the most in all of this is we didn’t make clear early on that parents get two things from school. They get education and they also get child care. Those are both valid, critical needs,” said Alix Gallagher, the director of strategic partnerships for Policy Analysis for California Education, which has been advising districts across the state.

Figuring out new boundaries also depends on what the school is asking. While parents and kids settled into their new — sometimes screen-heavy — routines over the summer, schools pulled together distance-learning plans. Many schools faced pressure from parents desperate for help with child care or worried about their children falling behind in school. Ed-tech companies hawked their apps and platforms to superintendents, while education professionals pushed for more research-based solutions.

The result is a jumble of methods that vary wildly between states and individual school districts.

Some kids don’t have live classes at all and only watch videos or use apps to turn in schoolwork, which can help students unable to get online during normal hours. Others tune in for short spurts to take part in live classes, lectures or small group time. Many schools are using videoconferencing software such as Zoom, Microsoft Teams and Google Meet not just to teach, but for the entire day to keep students on task and make sure they are going through the same motions of in-person school.

Gallagher said schools need to focus on designing days around what gives kids meaningful interaction and what fulfills their social needs. She recommends a mixture of lessons that deliver information, like a video or lecture, plus activities for actively engaging with the lessons, like practicing writing or doing math problems. After that, use a tool like Zoom to discuss what they have learned and actually interact with the teacher and other students.

Her son recently started school remotely and has had to sit through 70-minute geometry lectures. That length of time can be too much for children in person and is probably harder over video, where there isn’t the same social pressure and teachers miss out on key cues from seeing students, Gallagher said.

High school science teacher Margaret Lorentzen has noticed all the small differences with communication over video that make it harder for teaching, like the lag that can happen when a teacher is talking, the missed visual cues and the feeling of talking over people in a group discussion.

She taught remotely in the spring and just had her first day of classes again this week in Seattle. It’s 20 to 30 minutes of Zoom time per each 80-minute class, with up to 33 students who don’t have to turn on their cameras unless they choose. Used to walking around a classroom and assigning lab experiments, Lorentzen is adjusting to the physical constraints of online learning but is happy to have a way to see her students again.

“The best thing about today was actually seeing students, and I think for many of them, they’re just so starved for any type of interaction outside their families, they turn on their cameras,” said Lorentzen.

She said teachers should try to understand what their students are dealing with, including why they may want to keep cameras off or why they can’t make live classes, and work with them.

Learning online also brings some unique challenges as students learn to navigate new school rules — and even shared WiFi issues.

When Sarah Perez’s freshman son turned off his camera to run to the bathroom during a Zoom lesson recently, his teacher kicked him out of the class. Perez was on a meeting in another room, but her oldest daughter was nearby and could hear the teacher warning him to turn it back on. Her three kids have also been locked out of classes after their home WiFi, which the family is all sharing, has gone out. None of her children enjoy being on camera, especially her youngest daughter, who is in middle school.

“I feel like there’s no acknowledgment of these children as people, we’ve just moved the over-policing of schools to our homes,” Perez said.

A teacher in Dallas, Perez tries to be more flexible with her own students, who are kindergartners and possibly logging on for the first time. She sees a contrast between the school where she teaches primarily low-income students and the better-funded district where her children go. Her students’ caregivers say they’re concerned about their health, safety and access to food, while the parents at her children’s school have been pushing harder for face-to-face learning.

All screen time is not created equal, experts say, and some kinds are better than others. Anything that promotes children‘s socialization, like FaceTime with friends or a video conference with the teacher, can be beneficial. Activities in which children feel engaged are better than something completely passive, like watching YouTube, or even something somewhat interactive, like playing video games.

But adding hours of video conferences filling up to six hours a day can change the calculus, education experts say.

“Real classrooms involve all kinds of interaction, with the teacher and among the students, so that’s what teachers are finding so difficult to replicate online,” said Sonia Livingstone, a political science professor at the London School of Economics and the author of “Parenting for a Digital Future.”

She recommends teachers break up the format of their instruction during the day. For their part, parents should be tolerant if their child gets restless and needs to move, and try to balance their school and recreational screen time with in-person interactions and physical activities.

Experts say to talk to your children to make sure they are okay and to make any screen-time decisions with them. If video games help them unwind after a day of video chatting, it might be good to keep for their mental health.

Whatever their schedule, screens are an unavoidable part of learning remotely for millions of students this semester. Video conferences, when used to interact with students, can be a healthy social activity for kids who are isolated at home, experts say. But tasks that are just listening and watching might be less valuable if done too much for the sake of filling up a school day.

“It’s not solely about the issue of screens, but what’s happening on those screens,” said Josh Golin, executive director of the Campaign for a Commercial-Free Childhood, an advocacy group.

His organization has been calling on schools to limit the amount of screen time they’re asking of students, and to do more of the kind of remote education that experts agree is better for students. That means small groups, shorter interactive classes with teachers over video and project-based learning that children can pursue without a computer.

The group especially wants schools to be careful about using ed-tech applications, which he said can outsource some things typically handled by teachers to algorithms. His biggest worry is that changes that are happening, like moving from in-person interaction to learning on screens and through apps, could be permanent.

“There are no great solutions right now, and that’s really unfortunate. The people who are doing the most arguing, parents and teachers, it’s none of their faults. This is a virus that was mismanaged by our country,” Golin said.

For parents like Barnett and Perez, seeing their children unhappy is the hardest part. Barnett said she wishes her school would offer prerecorded options so her daughter could learn on her own time. Perez has already talked to the school administrators about loosening up the rules.

“There’s a lot going on and we need to calm down and just let things shake out instead of over-policing this whole situation and stressing out these young little lives,” said Perez. “There’s a way we can just be calm and offer grace, teachers to students and parents to teachers — all around. Let’s just take a deep breath.”