Before classes commence each day at Hampstead Hill Academy, the pre-K-through-8 public charter school across from Patterson Park in Baltimore, all student cellphones go into locked pouches. Six hours and 45 minutes later, at the end of the school day, students hold the pouches against a special magnet, the pouches open, and the kids have their phones again.

That’s the new routine, instituted over the summer by the school’s administrators.

The principal, Matt Hornbeck, says the policy not only reduces the risk of in-class distractions but sends a broader message about the detrimental effects of social media on tweens and teens in their middle school years.

Despite repeated warnings to parents — and a national effort to hold off giving kids smartphones until 8th grade — plenty of younger ones have them.

“Pretty much everyone in fifth through eighth grade,” Hornbeck said, when I asked how many students at Hampstead Hill had a phone. “That’s 390 kids.”

But it’s not like the school in Southeast Baltimore had a widespread problem with students texting and checking TikTok during class, says Assistant Principal Mike Lucas. The idea is to keep that from happening but also to provide a stop-and-think moment for children and their parents.

Kids do not need their phones during the school day, and the evidence is increasingly clear that too much screen time is bad for adolescents.

Both the Centers for Disease Control and Prevention and the U.S. Surgeon General, Dr. Vivek Murthy, agree on that.

In May, Murthy issued a warning: “Teens who use social media for more than three hours a day face double the risk of depression and anxiety symptoms, which is particularly concerning given that the average amount of time that kids use social media is 3 1/2 hours a day.”

The CDC found an alarming rise in sadness, loneliness and feelings of hopelessness among teenage girls in the decade ending in 2021. “While all teens reported increasing mental health challenges, experiences of violence, suicidal thoughts and behaviors, girls fared worse than boys across nearly all measures,” the agency said.

Over the summer, Baltimore joined other public school systems in Maryland in a lawsuit against the big social media platforms, charging that they’ve exploited the psychological vulnerabilities of children and caused a mental health crisis.

In researching the subject further, Hornbeck and Lucas were troubled by what they learned. So they opted for the locked pouch system, following the example of two other city schools to give their students a break from phones and all that flows from having one.

After a series of meetings, Hornbeck and his staff settled on a plan to subscribe to Yondr, a company that provides a neoprene pouch for each student’s phone.

“The students carry their own pouches; they put their names on them,” Hornbeck says. “They show a staff member that they’re putting the phone — and their smartwatch, we don’t allow them either — in the pouch, and then they press the button, and it locks.

“We don’t take the phone away and lock it up. We all get nervous if somebody takes your phone away from you. So the student has the phone on their person or in their backpack. The only reason we would take it and keep it in the office is if they forgot their pouch.

“And then, at the end of the day, we’ve got 15 unlocking stations, or unlocking docks, and they just click it and unlock it, and take it out of the pouch and it’s theirs.”

I watched this the other day as HHA middle schoolers were dismissed. Boys and girls filed into the wide classroom corridor, pulled out their Yondr pouches and crowded around unlocking devices, some on small service carts, some held by teachers.

All things considered, it was an orderly process, and it didn’t take long. When it was over and most students had reached the sidewalk of Linwood Avenue two flights below, Hornbeck looked at his watch. “Dismissal was at 2:40 p.m.,” he said, “and it’s now 2:42.”

Parents have approved of the lock-up policy, he said.

But several of them had a question: What if there’s an emergency?

“If there’s an emergency, we don’t want kids pulling out their phones and texting their parents,” Hornbeck says. “We want to do what we’ve been trained to do throughout the year, whether it’s a hurricane drill or an active shooter, fire drill, whatever it is. If something like that would ever happen, as soon as we got the all-clear, we would ask everybody to take them out and turn their phones on.”

The fact that the students have their phones with them — in a locked pouch, not stored all day in a school office — satisfied parents who were concerned about emergencies.

Another thing: The phones are only unlocked at the end of the day, not at lunch hour.

“We want them to talk to each other during lunch,” says Lucas, making the point that if the pouches were unlocked at lunch, kids would be so busy catching up on text messages and social media they’d hardly eat, much less converse with friends; the building of the school community would suffer.

“We spend hours and hours a day on our phones,” Hornbeck says. “We’re giving the kids six hours and 45 minutes to be together and to be thinking, not worrying about the phone.”