Is the biggest classroom in the world the screen in front of you?

The screen – whether on a laptop, a tablet, a mobile phone, even that quaint old device a television set – plays a huge part in the lives of young people.

When a student protest ended in London this month, the last knot of marchers did what came naturally – they sat on the edge of the pavement and got out their laptops, glowing like some kind of digital campfire.

Entertainment, socialising and information have become screen-shaped. And a cluster of global online learning projects are bringing education into the frame too.

Among those attracting attention is the Khan Academy, the US-based free online tuition service, which helps youngsters to catch up on lessons and bright children to stretch themselves further.

BBC News – Screen test for the online classroom.