One of the most impressive innovators in education today is Salman Khan, founder of Khan Academy, an online learning portal. A former hedge fund analyst from Boston, Khan stumbled upon the idea for his free web-based academy while trying to teach math to cousins in New Orleans. In an effort to bridge the time and distance gap, he started making 10-minute videos of math lessons and posting them on YouTube. Much to his surprise, Khan found his cousins preferred learning from him via YouTube to learning from him in person. While they were grappling with new concepts for the first time, it was less intimidating to have their cousin not hovering over them, asking, “Did you understand this?”

Soon, Khan noticed other students had discovered his videos and were using them to learn math. The feedback from these unintended beneficiaries was encouraging and heart-warming. (“This is the first time I smiled doing a derivative.”) Realizing he might have an innovative educational model on his hands, Khan – who by then had moved to California with his family – left the hedge fund and launched his online academy with himself as sole faculty member. His portal now has more than 2,200 short video lectures. Most of them are about math; additional topics include physics, history and economics, among others. The total number of lessons Khan has delivered over the past five years is now nearly 42 million.

Khan discussed some of this background at a TED talk earlier this month. For those who might have used Khan Academy math videos in the privacy of their homes to help children with their homework, one of the most interesting points of his 20-minute lecture is about how teachers are using the videos to flip the educational model in the classroom.

According to Khan, several teachers have written to him, saying, “You’ve already given the lectures, so we assign watching the lectures for homework. And what used to be homework [solving problems] is now done in the classroom.” This shift has had a non-intuitive outcome, according to Khan, because “when teachers do that, they remove the one-size-fits-all lecture from the classroom and let students watch self-paced lectures at home.” What happens in class is interactive problem solving – which means, in effect, that the “teachers have used technology to humanize the classroom,” he says.

The TED video is worth watching, whether you are a teacher, parent or student. Towards its end, one of Khan’s famous admirers shares the stage. Still, for all the acclaim Khan has received, he comes across as a modest young man who is faintly puzzled by his success. “I was an analyst at a hedge fund,” he says. “It’s very strange for me to do something of social value.”