Minister for the Environment Roseanna Cunningham recently went straight from a session with fourth-year students at Perth Academy to BBC Radio 4's Any Questions, where one of the issues raised at the school came up again: voting rights for prisoners. The radio audience was broadly in favour of these, while the school class had been almost unanimously against.
"Young people tend to be conservative," the minister commented at the school. This view was confirmed by a survey of their research for a new cross-sectoral project on sustainable futures. One girl advocated harsher, American-style prisons in Scotland, while a boy wanted to prosecute girls for under-age sex, as well as boys, with the class largely in agreement.
On environmental matters, however, the consensus was progressive, with nuclear energy rejected and renewable energy a firm favourite.
The class will eventually deliver formal presentations on these subjects as part of Visions and Ideas for Change, a project devised by Zoe Lloyd, a PhD student at St Andrews University. "When I was trying to get these ideas into schools, I talked to several," she says. "Only Perth Academy worked with me to put them into practice. It seemed too daunting and different, I think, to the others."
But that was the selling point for Perth Academy's English teacher, Sarah Duffy, who says: "If I'm daunted, I know the pupils are going to love it."
Key aspects of the approach, she says, include not being prescriptive and providing no answer when pupils wonder what they should do next. "That's one reason the topics on this project are so wide-ranging," she adds. "They were all their own ideas."
Education for sustainable development is one of those leaden phrases that freeze the brain. So Ms Lloyd's doctoral research - and the Perth project that is now part of it - is built on the conviction that getting young people active in global issues involves building their confidence to "articulate, share and justify their ideas and aspirations".
"Unless people are driven by a vision of a better society," she says, "there is little hope for sustainable development - or the future."
It is clear that more than just academic interest motivates her research, and the pedagogy she and Miss Duffy have developed at Perth - in four lessons a week for over a month - has stoked passions in the pupils that are every bit as strong.
"Normally in school it's very structured," says Sarah Rankin. "Sometimes you know what you want to do, but the structure does not let you. With this project, we got to look into what interested us."
The contact with St Andrews helped make the work stimulating, says Eliza Sheldon. "We had a whole day at the university. In school, everything you try to do on the computer is blocked by the council.
"At the university, we had a student facilitator for each group, who helped develop our ideas using mind-maps. Then we did research on the computers. We could find anything we wanted."
A little direction was needed initially to assign pupils to topic groups, since some of the eight - health, justice, food, green buildings, wealth and consumption, energy, governance, media, entertainment and education - were more popular than others.
"There were no volunteers for my group - wealth and consumption," says Harriet Williams. "But once we got into it, we found really interesting stuff, like the Happy Planet Index." This assigns a number not just to a population's happiness, but also to the ecological efficiency with which it is delivered. "So people in a country that uses lots of fossil fuels might have all the necessities," Harriet explains. "But it wouldn't be a happy country."
Working alongside a class teacher opened Ms Lloyd's eyes to the practical aspects of getting sustainable development into schools, she says: "I would now be keen to use what we've learnt in other schools."
In turn, the pupils have been immensely motivated, says Miss Duffy. "Students work in groups and we have a whole-class session at the beginning and end," she adds. "There is a wiki for them to share what they're doing. They have freedom within a structure. This is what learning should be like."
Top of the Happy Planet Index is Costa Rica, with major fossil fuel users, such as America and China, near the bottom. The UK comes roughly in the middle. See: www.happyplanetindex.org