Ever since the first elementary school teacher rolled the first television set into the first classroom to air the first course offering from “educational television,” there’s been the hope and the promise that technology would revolutionize the way teaching and learning would be done.

As things turned out, educational television became public television and went off in a different direction. And despite the advent of the personal computer and the Internet, most education today remains much like it’s been for hundreds of years: one teacher, 30 kids, textbooks and a blackboard.

Now that’s about to change. The cost of education has gotten so high, student achievement has become so disappointing, and the technology and computerized pedagogy are now sufficiently developed and ubiquitous that the long-awaited revolution in education is about to begin.

It’s not just me who thinks so. Just last week, at a digital run-up to the G-8 summit meeting in France, Rupert Murdoch announced that his News Corp. would be getting into the business of developing digital learning content and systems “in a big way.” There is now an entire ecosystem of venture capitalists, social entrepreneurs, angel investors and philanthropists eager to provide risk capital for technology-based education startups. A blue-ribbon advocacy group, the Digital Learning Council, was launched last fall by former governors Jeb Bush of Florida and Bob Wise of West Virginia. And, naturally, there’s even a new blog devoted to the subject, EdSurge, launched by my former Washington Post colleague Betsy Corcoran.

The person who has emerged as the pied piper of this movement, however, is Salman Khan, a former math geek and young hedge fund analyst who five years ago began making 10-minute videos to help his struggling nieces with their math homework. For convenience sake, he posted them on YouTube and found to his surprise that other people liked them, as well.

Today, the Khan Academy Web site boasts 2,300 separate math tutorials, from simple addition to vector calculus, that have been viewed more than 50 million times by more than 2 million students and are in active use in more than a thousand classrooms across the country.

Khan has no training or experience in teaching, and his videos are relatively crude by the standards of online course material produced by traditional educational publishers. They consist almost exclusively of Khan explaining things in conversational English while doing the equivalent of writing on a blackboard, which he does without benefit of a script or even a second take.

“I teach the way I wish I had been taught,” said Khan, who majored in math at Massachusetts Institute of Technology before earning masters’ degrees in computer science, electrical engineering and business administration.

Khan’s “lectures” are now accompanied by exercises that test whether the student has mastered the concepts, powered by an algorithm that makes the questions harder or easier depending on how well the student did on previous questions. There’s also a “dashboard,” where coaches, teachers and parents can monitor how their charges are doing. In addition to math, there are a few offerings in accounting, economics, history and preparation for the SAT, with more on the way.

Textbook publishers such as Pearson and McGraw-Hill, and online education companies such as Herndon-based K12 or The Washington Post Co.’s Kaplan division, for years have had similar digital offerings, which are already used widely as core curriculum by home schoolers and charter schools and as supplement to more traditional teaching in a growing number of public schools. So in a way, it is curious that it is Khan who has become, as Bloomberg Businessweek put it last week, “a quasi-religious figure in a country desperate for a math Moses.” In the past year, Khan has been featured on the nightly news programs of NBC and ABC, interviewed by PBS’s Charlie Rose, spoken at the Aspen Ideas Festival and given a TED talk introduced by Bill Gates.

Surely one reason for all the attention is that, unlike virtually all of the other offerings, Khan’s are available to anyone for free, produced by his nonprofit “academy” with the philanthropic support of such luminaries as Gates, Google, venture capitalist John Doerr and Netflix founder Reid Hastings. Khan Academy, in effect, offers itself as the open-source alternative to the proprietary “walled gardens” of the for-profit education industry, a disruptive new player whose free offerings could one day do to Pearson or the University of Phoenix what Napster did to the music industry, or Craigslist and the Huffington Post have done to newspapers.

What is even more exciting — or threatening, depending on your point of view — is what the Khan Academy model might do to the rest of the educational establishment.

Think about it for a minute. If education moves to a teaching model in which students learn through online tutorials, exercises and evaluations created by a handful of the best educators in the world, then how many teachers will we need preparing lesson plans and delivering lectures and grading quizzes and tests? Surely we’ll need some for one-on-one tutoring, or to run small group discussions, or teach things that can’t or shouldn’t be taught online. Despite assurances to the contrary, however, there’s likely to be fewer than we have now — fewer but better-paid with more interesting jobs — just as has happened in nearly every other industry that has gone through a similar transformation.

The disruption doesn’t stop there. If students are allowed to progress through each subject at their own pace, they won’t be second-graders or sixth-graders any longer, since at any time they are likely to be at different grades in different subjects. Indeed, the whole notion of a 45-minute “class,” or the six-hour “school day,” or even the August through June school “calendar” — the entire framework of the educational experience — will become somewhat irrelevant. And as Khan loves to point out, grading will suddenly become simple: Everyone gets an A in every course, with the only question being how long it takes each student to earn it.

Given these implications, you can understand why the education establishment has been in no hurry to embrace a digital future. The battles over standardized testing and adoption of common national standards were just the warm-up. Now that the opposition to them has been largely overcome, capital and creative talent will pour in to develop both the hardware and the software of the new education technology.

Over the next decade, look for teaching to be transformed from an art into something much closer to a science, look for learning to become highly individualized, and look for education to go from being a cottage industry to one that takes full advantage of the economies of scale and scope. And as in every other industry, look for quality to go up and cost to go down.

Sal Khan, of course, had none of that in mind when he set out to help his niece Nadia with her seventh-grade math homework. But the fact that he and his “academy” have drawn so much support and attention is a pretty good indication that this revolution is finally about to begin.