"IT IS possible to teach every branch of human knowledge with the motion picture," observed Thomas Edison in 1913, predicting that books would soon be obsolete in the classroom. In fact the motion picture has had little effect on education. The same, until recently, was true of computers. Ever since the 1970s Silicon Valley's visionaries have been claiming that their industry would change the schoolroom as radically as the office - and they have sold a lot of technology to schools on the back of that. Children use computers to do research, type essays and cheat. But the core of the system has changed little since the Middle Ages: a "sage on a stage" teacher spouting "lessons" to rows of students. Tom Brown and Huckleberry Finn would recognise it in an instant - and shudder. Now at last a revolution is under way (see article). At its heart is the idea of moving from "one-size-fits-all" education to a more personalised approach, with technology allowing each child to be taught at a different speed, in some cases by adaptive computer programs, in others by "superstar" lecturers of one sort or another, while the job of classroom teachers moves from orator to coach: giving individual attention to children identified by the gizmos as needing targeted help. In theory the classroom will be "flipped," so that more basic information is supplied at home via screens, while class time is spent embedding, refining and testing that knowledge (in the same way that homework does now, but more effectively). The promise is of better teaching for millions of children at lower cost - but only if politicians and teachers embrace it. Why is this time different? Largely because a number of big changes are coming at the same time: high-speed mobile networks, cheap tablet devices, the ability to process huge amounts of data cheaply, sophisticated online gaming and adaptive-learning software. For instance, new interactive digital textbooks with built-in continuous performance assessment can change in real time, depending on what and how much the pupil using it is learning (sometimes with the pupil being unaware that he or she is being tested). New data-mining software is able to predict when a pupil is likely to fail at reading or mathematics without special attention, allowing the teacher to intervene before it is too late. Yes we Khan Higher education is in the vanguard. Barely a year from its launch, Coursera, one of the pioneers in offering "massive open online courses," now boasts more than 3.9m students worldwide, taking courses supplied by 83 partner institutions. Colleges have always been keen to experiment with technology: Britain's television-based Open University is now 44 years old. But this time schools are following. Four years after Salman Khan gave up his job at a hedge fund to focus on making maths videos, the Khan Academy has 6m registered users, who solve (or try to solve) 3m problems a day, and it has broadened its curriculum far beyond maths. It is spreading beyond America, too. Carlos Slim, one of the world's richest men, is said to be paying for a version of Khan Academy's curriculum to be developed for schoolchildren in his native Mexico. Edtech has collected other impressive advocates. Bill Gates calls this "a special moment" for education. Private-sector money is piling in. Rupert Murdoch, hardly a rose-tinted-specs technophile, is allowing Amplify, his digital education business, to run up losses of around $180m this year in hope of dominating an edtech market that News Corporation reckons will soon be worth $44 billion in America alone. GEMS, a Dubai-based education provider, wants to expand its use of technology in India and Ghana to reach children in remote areas. Others are not so sure. Many parents already blame the "dumbest generation" on too much gaming, always-on computing and illiterate texting. Teachers may use edtech websites, but their unions are suspicious of anything suggesting that schools could get along with fewer teachers, and they dislike the idea of private companies such as Mr Murdoch's News Corp making money out of education. There are also worries about privacy: edtech companies will end up with a vast store of personal data on pupils. It seems to work Most of these fears are overdone. For-profit companies have long been in the business of selling printed textbooks, and there is no reason why data-privacy laws cannot extend to students. The biggest question remains: will children learn more? That in turn relies on the teachers, because even the best technology will get nowhere without their support. The evidence on the efficacy of edtech comes largely from America. Most of it suggests that when teachers have been properly trained, it works. Low-income students at Rocketship, a chain of charter schools in San Jose, California, which also use the technologies, outperform those living in the wealthiest districts in the state. Having performed well in various pilot programmes, Khan Academy's adaptive software platform is now being rolled out across Los Altos, one of America's wealthiest and best-performing school districts. Edtech will boost inequality in the short term, because it will be taken up most enthusiastically by richer schools, especially private ones, while underfunded state schools may struggle to find the money to buy technology that would help poorer students catch up. Governments will have to invest to allow them to do so. Some already are. In South Korea high-speed internet access is the norm in schools. Barack Obama recently promised that America will follow. Laws may have to be changed to allow pupils to study with those at a similar stage of learning rather than be grouped according to their age. But the biggest challenge for many politicians will be confronting the enormously powerful teachers" unions. Parents and taxpayers should stiffen the politicians" spines. Education has proved stubbornly resistant to the improvements in productivity that technology has brought to other jobs. This wave of edtech promises to change that. Technology has supposedly been on the verge of transforming education for over a century. This time it looks as though it will.