The famous First World War recruitment poster flashes up on the whiteboard. Lord Kitchener's finger points at the class. He wants you for his army.
"How would that make you feel, if someone was pointing in your face?" asks English teacher Beth Schofield. She places her hands on her hips and stands, chest broad, feet apart, surveying her class.
A few pupils put up their hands. "Intimidated," one suggests.
"Yes," Schofield says, marching purposefully across the classroom and then leaning over a desk to ask a pupil a question.
Schofield, a newly qualified English teacher at Aldersley High School in Wolverhampton, is trying out power poses in the classroom. Power poses are stances associated with triumph or confidence. Raising your arms into a V-shape, like a winning athlete, is a power pose; so, too, is putting your feet on the table and your arms behind your head. Open body language suggests power. By contrast, curling in on yourself and closing up your body conveys a lack of power and a lack of confidence.
As outlined in a TED talk by Harvard social psychologist Professor Amy Cuddy, power poses are supposed to change the way that others perceive you and, ultimately, the way you perceive yourself (see panel, below).
But how useful could power poses be for teachers? TES set up a small experiment at Aldersley High, with Schofield as the first of three teacher test cases.
Case study 1: `It didn't feel natural'
Every time she addresses her pupils, Schofield stands with her feet apart, her shoulders wide and her hands on her hips. Once, she tries raising both hands to her head, elbows out, but quickly lowers them again.
"I just couldn't do that," she says afterwards. "It felt like I was doing Heads, Shoulders, Knees and Toes."
In a post-mortem of the class, Schofield comments on how artificial much of it felt. "Naturally, I cross my legs," she says. "Standing still, with my legs shoulder-width apart - that didn't feel natural. That felt quite manly.
"It was quite difficult to be still. I'm normally quite movey-turny. Maybe moving around too much can confuse the students. Sometimes I can hear my bracelets jangling and I think that must be quite annoying. If I'm still, they know exactly where I am, where the instruction is coming from."
In fact, the power poses were sufficiently different from Schofield's usual classroom style to have raised pupils' eyebrows.
"She seemed more powerful," says 13-year-old Brandi Thompson. "Like she knew what she was doing."
Brandi pauses and glances at her teacher. "Not that she doesn't usually. But she looked like she had everything under control. She knew what she was doing and how to handle it."
"Usually, we might talk when she's talking," adds 14-year-old Khatira Hakimi. "But today everyone knew she was serious and that we had to pay attention. And her voice was projecting more when her back was straighter and her hands were on her hips."
Brandi laughs. "We thought she was just posing."
Schofield's lesson was about George Orwell's Animal Farm, and its links to historical propaganda. This - and the accompanying power poses - is picked up during the next period by head of performing arts Cat Shepherd.
Case study 2: `I'm a dictator'
Cat Shepherd strides into the classroom. Within minutes, she is sitting with her feet on the table and her arms behind her head.
"What do you call a system where one person has control over everyone else?" she asks the class. "It begins with a D."
"Dictatorship?" a boy at the back says.
"Very good." She swings her feet from the desk and stands up again. "A bit like this classroom. I'm a dictator."
She brings up a Russian propaganda poster on the whiteboard. Vladimir Putin is standing in the centre, his chest broad, his shoulders wide. His left hand is pointing into the distance; around him, patriotic Russians are gazing in the direction he is indicating.
"We follow Putin!" Shepherd says of these figures. She stands to the side of the poster, her shoulders similarly broad. With her left hand, she points at Putin; she is mirroring his pose exactly.
"Yes," she says once the lesson is over. "I was Vladimir Putin for about half an hour, just standing around pointing."
But, Shepherd adds, the role of classroom dictator is not entirely unfamiliar to her. "Maybe not the feet on the desk. But I'll sit on a chair the wrong way round."
In the past, she says, she used to put her feet on the desk during lessons. But a previous school suggested it could be seen as rude by people from some cultural backgrounds. This, however, was not the reaction she received this time round.
"When I sat there with my feet on the table, those two kids were both leaning forwards, they were engrossed," she says. "They were on it like a car bonnet."
Case study 3: `I was trying to hide'
The final teacher to try out some new poses is assistant vice-principal Steve Kendall. Like Shepherd, he is a natural power-poser. Unlike Shepherd, however, he is trying out the opposite: poses of powerlessness.
So he sits on a desk, his shoulders rounded. He touches his neck and his face. Then he clasps his arms around himself. Speaking to pupils, he crouches by their desks, his hand on his chin.
He struggles with the poses, though, and every so often finds himself reverting to his usual stance: head up, legs apart, arms spread open.
"I found it very hard," he says afterwards. "I was trying to hide behind my hand for most of the lesson, which just feels weird. Towards the end, the kids were just looking at me and laughing."
Although Kendall is an arts and drama specialist, his power-free lesson was in religious education. "This is not my subject at all," he says. "Coming in as a non-specialist, it's really important that you let the pupils have confidence in you by showing confidence in yourself.
"But it's quite a big deal for teachers to deconstruct what they do. The shufflers. The people who count fingers all the time, the hand-swayers. Tappers on tables. You find people checking watches and fiddling with rings. Biting lips. People do it all the time, but it does come across as either distracting or anxious."
Training as a drama teacher, Kendall was taught the importance of body language. "It's massively important," he says. "But it can be affected by the organisation of your classroom, the ability to circulate. Being impeded from getting somewhere immediately changes your body language.
"Also, be aware that there shouldn't be anything other than a wall between you and your back. It gives you that little bit of confidence, to know that you're not missing anything."
But factors other than body language also come into play. Kendall stresses the importance of eye contact: "Being able to eyeball a child - not in a nasty way, just `I'm listening to you, I'm talking to you' - it's a way of keeping them on their toes," he says.
"And your primary teaching tool is your voice. Your body language is there to support that. But it can be undermined without good projection and good diction."
Kendall, Shepherd and Schofield all acknowledge that power poses are not a one-size-fits-all solution.
Schofield points out that when one of her pupils was struggling with a task, leaning over him with her hands spread across the desk was not necessarily the best response. "He was intimidated," she says. "But I wanted to sit down with him and be nurturing."
Shepherd adds: "It's about getting the balance. Getting the stillness and the nurturing, but also being in authority in your classroom."
The key, they believe, is for the power pose to fit the people and the situation. And the pupils are not the only significant - and changeable - element in a classroom, Schofield notes. Looking through examples of power poses before her lesson, she had turned slightly pale at the image of someone with their feet on a desk.
"The teacher has to feel comfortable in that position for it to have the right impact," she says. "If you feel comfortable, then surely you should be able to command your classroom."
"That's the key," Kendall agrees. "Getting in early and embedding good practice. And stop embedding bad practice."
But he concedes that this makes being a new teacher all the more difficult, especially if that teacher is training on the job. "If we're saying there's a value to these skills and the skills are developed over time, then hitting the ground running becomes harder," he says.
`In high-power poses, people experience a 20 per cent increase in testosterone'
In her TED talk "Your body language shapes who you are", Harvard psychologist Professor Amy Cuddy explains: "We decided to bring people into the lab and run a little experiment. These people adopted, for two minutes, either high-power poses or low-power poses.
"So this is what we find. Risk tolerance, which is gambling, we find that when you are in the high-power pose condition, 86 per cent of you will gamble. When you're in the low-power pose condition, only 60 per cent [will], and that's a whopping significant difference.
"Here's what we find on testosterone. From their baseline when they come in, high-power [pose] people experience about a 20 per cent increase and low-power people experience about a 10 per cent decrease.
"Here's what you get on cortisol. High-power people experience about a 25 per cent decrease, and the low-power people experience about a 15 per cent increase. So two minutes lead to these hormonal changes that configure your brain to basically be either assertive, confident and comfortable or really stress-reactive and feeling sort of shut down. And we've all had the feeling, right?
"So it seems that our non-verbals do govern how we think and feel about ourselves, so it's not just others, it's also ourselves."
Watch Amy Cuddy's TED talk at bit.lyCuddyTED
Start the discussion with a PowerPoint about different types of body language.
Play a game to show students the power of body language to convey different messages.