As she tries to persuade one young lad to come down from a table and not throw the class telephone out of the window, maths teacher Liz McBride explains why Monday morning is not the best time to catch Ballikinrain boys at their most teachable. "Drink and drugs can play a big part in the families and communities they go back to at weekends. So this is usually our toughest morning of the week."
The presumption of mainstreaming has increased the challenge for schools such as Ballikinrain, says head of education Kyle Fleming. "We get young people with greater emotional and behavioural difficulties than before. It takes a special kind of person to teach them. They are not easy kids."
Just how hard becomes clear as the morning progresses, and Liz and learning mentor Moira Car-michael teach a succession of classes with little inclination to be taught. The numbers in each class are small, but the random energy and unpredictability of a few agitated early teenagers in a confined space has to be seen to be believed.
"I've occasionally gone home covered in bruises," Liz says calmly.
That calmness is a quality that clearly stands her in good stead with youngsters who drive most adults to distraction and get treated anything but calmly outside school. Their behaviour now makes that inevitable. But they didn't start out that way, and inside each is a small boy who wants the approval of the adults he looks up to.
Reaching that boy takes calmness, patience and persistence and anything up to half a lesson, it seems. But eventually it happens and the lads get down to trying to solve their maths problems. Even so, attention spans are short and questions not always maths-related:
"Did you see Celtic won the Cup yesterday?"
"How much would you charge if you were a prostitute?"
"What the **** are you talking about?"
At times, it feels like a barrage of abuse. For someone advised strongly against becoming a teacher while still at school, because she was "too shy and quiet", it must be hard to take. "Not at all," Liz says. "It's about building relationships. If they like you and respect you, they will work for you - eventually. They try to push you away because they're used to adults leaving them. They test you. So if you make it clear you're not going anywhere, you do get through to them.
"Sometimes they'll say: `You're only here because you're paid to do it. You don't care.' Then they'll see me in the units at lunchtime or after school, and they realise it's not true."
Run by Crossreach, the social-care arm of the Church of Scotland, the school is located in an old castle in the heart of the Stirling countryside. It currently has 25 residential and nine day boys, aged eight to 14, taught by 16 teachers, five classroom assistants and one learning mentor - a classroom assistant with additional experience and responsibilities.
The boys are assigned to one of six units, each with a kitchen, recreational area and, for residential lads, sleeping quarters. Units are managed and run by the other half of the staff at Ballikinrain, the care workers. But a teacher can choose to work extra shifts as part of a care team, at weekends or evenings. "I've done both," Liz says. "I'll work an evening a week. On that day I'd be on from 8.30am till 11pm. It is long, but it doesn't seem like it."
The pattern of the first class is repeated, with variations, as the day progresses. When the boys first come into the room they are all over the place, literally and mentally, but Liz and Moira gradually get them settled at tables and working on their maths problems.
Besides calmness, persistence and caring, one further factor is needed to make this happen, to make lessons about learning and not just coping. "They have to realise that if they don't do the work, there are consequences," Liz explains.
"When I first came here three years ago, there was a TV on in the room constantly. It took the pressure off, but it gave the boys too easy an option. So that had to go. I wasn't popular for a while."
"By working closely with care teams, a teacher can make sure boys who refuse to work in class must do so in the units after school, when colleagues are playing or relaxing.
The basis of the whole approach is that Ballikinrain pupils are not bad boys - they are boys to whom bad things have happened. "I don't think there's a bad kid in the school," Liz says.
"This is a really rewarding job. I love it and I miss it when I'm not here.I wouldn't go back to mainstream. You have to be aware of the dynamics, the moods of each child. You watch them in assembly, so you know what to expect in class. You know their backgrounds; most have had a really rough start to their lives. They've had to grow up too quickly.
"So you see them after they've been here a while, and maybe they've a wee smile on their face or they're skipping about happy. They are getting the chance to play and learn and to be wee boys again."