The Khan Academy website allows pupils to follow a structured course through a subject, with banks of videos and questions to answer, in a growing number of languages. It’s not a replacement for school or teachers, says Mr Sinha. And in fact the academy is setting up its own real-world summer school and is working with schools in the San Francisco area in California.
But it does raise some big questions about the future functions of schools and universities – not least when US colleges are charging students $50,000 per year. The other striking aspect of the Khan Academy equation is the reach of such a small team of people. There are volunteers, but as of November 2011, there are only 20 full-time staff. Millions of students, scattered around the world, are being served by a staff the size of a primary school.