A crowd of first-year pupils looks on in disbelief as a strong man in a tracksuit straps on a harness, pauses and then throws all his strength into trying to pull a double-decker bus along the playground at Peterhead Academy in Aberdeenshire.
The youngsters fall silent and the cry of a distant seagull carries on the wind from the harbour. The strain shows on the man's neck.
Nothing moves for a moment, then slowly, painfully, the bus inches forward.
As it gathers momentum the youngsters gasp, then scream with excitement:
"Go Dave! Go Dave! Go!"
Dave Gauder's exertions are not simply about proving he can still perform the feats that won him the Strongest Man in the World title a few years back and 17 world strength records. "See how strong I am" is just part of his message to youngsters in schools around Britain.
"You may not think it to look at me today, but when I was your age I was small and shy," Big Dave tells the packed school hall 10 minutes later. "I didn't mix well and that made me a target. I was bullied."
As he surveys his audience, one lad voices the thoughts of 300 pupils: "I don't believe it."
"It's true. At first it was name-calling. Then they started to push me around and they said: 'If you tell anybody things will get worse.' So I kept my mouth shut.
"But that meant the bullies got more control and more power. They started to hit me and kick me. They made me rob and steal. I did it was because I was frightened, really frightened.
"I would do anything not to go to school, anything. I was the dunce of the class because I could never concentrate. All I wanted was the school bell to go. At break times I would run and lock myself in the toilets."
The moving tale of a small, scared boy who became a powerful, confident man holds the youngsters enthralled. His message will stay with them: "If you work together, if you help each other, you can do anything. Strength is not about muscles. It's about what is in your mind. It's about confidence.
"You saw me pulling that bus. I could do that because I believed in myself.
"If I can become the world's strongest man from that frightened little boy, then you can do anything you want to do."
At the end of his talk, Big Dave sets off to visit another school and Alan Giles, the principal teacher of guidance, directs the Peterhead pupils to an afternoon of anti-bullying workshops.
"There is much more to this than just an inspirational talk," Mr Giles explains. "It is part of enterprise education. Our whole first year will now go and work on an anti-bullying campaign. It's all about teamwork, negotiation skills and communication. They will produce an exhibition of banners, posters, logos and certificates."
Big Dave's visit was organised by Sandra Gates, one of Careers Scotland's national network of enterprise education support officers, which provides teachers with training and resources through its Schools Enterprise Programme as they try to deliver every child's entitlement of at least one enterprise activity a year.
Ms Gates explains the connection between an anti-bullying campaign and enterprise in education. "People think enterprise is just about running a business and making money, but it's much broader than that. Besides making and selling, enterprise can be about communications, community or the environment.
"I'm finding this anti-bullying campaign is the most popular enterprise activity in secondary schools around the north-east."
Sarah Hall, national manager of the Schools Enterprise Programme, also believes the benefits conferred by enterprise in education are precisely those contained in Big Dave's punchy message: confidence, teamwork skills and a realisation that strength of mind and self-belief make anything possible.
Sarah Hall, Schools Enterprise Programme, tel 07786 333859