How do you use a van-load of bedsheets, a local park and a helicopter to teach young teenagers about global diversity and the need to think sustainably about resources?

If you are an imaginative and energetic geography teacher like Daniel Raven-Ellison of Little Heath School, a maths and science college on the edge of Reading, and you are also co-ordinating your school’s citizenship curriculum, and want to use both subjects to raise important ideas with pupils about the world they are growing up in, this is what you do.

First of all you find an idea that looks promising. Then you write a detailed unit of work around it, try it out, tinker with it, try it out again and then, ambitiously, organise a complicated end-of-module exercise to translate the theoretical ideas the unit is based on into a massive visual aid.

In Daniel’s case it was the notion of ecological footprints - the area of land and water that is needed for a person, or a population, to sustain their particular standard of living - that caught his eye.

The device gives a vivid snapshot of how different lifestyles consume differing amounts of resources. The average person in the south-east of England, for instance, has a footprint of 6.8 hectares, while a sustainable one is thought to be about 2 hectares.

Daniel saw this as a useful vehicle for studying sustainable development and helping students develop skills and knowledge for global citizenship.

It offered links with science, maths and ICT, and would allow students to consider how they could make a difference.

Taking materials developed by a group of charities, including Oxfam and Save the Children, he put in additional activities and offered differentiated strands of work for varying ability levels. This scheme of work, now in its final draft, will be available on the QCA website later this year. Daniel has also acted as consultant on the topic for the Royal Geographical Society with the Institute of British Geographers.

The unit lasts half a term and introduces Year 9 students to the idea of ecological footprints, how they can be calculated, and why they are the size they are. It encourages them to work out the size of their own, the class’s, the school’s and their local community’s footprint, and gets them to consider what is the “right” size of footprint.

Activities vary from fun games, such as Twister and Jenga, which introduce ideas of carrying capacity and overdevelopment, to complex data handling as students produce graphs and maps comparing footprints from different countries.

Students are also asked to write an action plan to reduce the size of their footprint, and see how well it works.

“One of the key reasons for organising this unit is to give students a framework in which they can actively participate in their community, in class, at home, in their form and school as well as wider society,” he says. “Students are given the chance to act and reflect on their actions, and then to see if they have made a difference, by re-calculating the size of their footprints.”

The unit can be used by anyone, “whether you’re a liberal lefty, or prefer the traditional academic approach. It’s absolutely not just wishy-washy ‘development’ stuff. It’s about sustainable development, which is a very real issue for everyone.”

Year 9 students who have just finished the unit admitted to being perplexed at first. “I thought it was something in the shape of a footprint,” says Peter Bristow, 13. “It was really confusing,” says Megan Carter, 14. “But then when I learned about it I was really shocked at how all the different countries are different.”

“It makes you think before you act,” says Sarah Hood, 14. “Although it also makes you realise that it is difficult to reduce the size of your footprint, if you don’t want to change your lifestyle too much.”

Becky Sumner, 13, says: “What we learned was that if everyone had to have 6.8 hectares of land then you would need three and a half planets to support everyone in the world.”

To reduce this consumption, pupils talked about not taking overseas holidays, recycling, and buying local food, and plotted what changes they and their families could make.

“Instead of getting, say, Belgian chocolates, you could get English ones,” says Becky Sumner. “And you needn’t flush the loo when you only do a wee.”

Then came the grand finale. For three weeks, students in the lower school and sixth-formers begged old bed sheets from home and local linen suppliers. “Then we stuffed them all in a minibus and took them to the park,” says Peter Bristow. Once there, they were laid out on the ground to cover 6.7 hectares, a visible marking-out of the area of the planet that just one student at the school takes up.

Daniel Raven-Ellison, meanwhile, had been in negotiations with Fly Magic, a local helicopter company, which had agreed to fly over and photograph the result, but which then ran into difficulties with requests from the media, who wanted harnesses so they could lean out and take photographs. There was a nail-biting delay, but the result, when it finally happened, was impressive. The weather was good. The sheets were laid out in time.

Future Forests, an environmental company, agreed to send energy-efficient lightbulbs to Jamaica in order to “neutralise” the carbon used up during the event. Students were interviewed on local radio news, and the aerial photographs left an indelible impression on their minds.

“Instead of learning from worksheets, we’ve been learning from bedsheets,” says Becky Sumner.

“My mum read my action plan, and she’s trying to turn off the lights more now,” says Sarah Hood.

Daniel Raven-Ellison will be leading a half-day conference on Creative Geography Classrooms at the Education Show in Birmingham on March 19.

lFurther details on education for sustainable development: www.rgs.orgcategory.php?Page=maineducation