Merryn and Niall Anderson are doing their homework with the help of the most popular teacher on Earth.

There's no rush. He chops the material - which seems to include just about all the maths and science high school students do - into bite-sized bits. He stops himself if his talk starts to go over about 12 minutes.

The guy's a natural: smart, kind, enthusiastic and infinitely patient. He's probably actually getting ready for bed at this moment, somewhere in the United States. But Sal Khan's 3000-plus free instructional videos are very much live on the Khan Academy site and threatening to turn schooling on its head. A bright future, say some. Another dead-end gimmick for the teaching profession to deal with, say others.

Whatever the outcome, right now Khan and his thing are wildly successful. There's the Time cover, the US 60 Minutes segment and the TED talk - the modern trifecta of next-big-thingness.

He was an analyst working for a hedge fund when his cousin asked him for help with her algebra homework. He recorded a tutorial and placed it on YouTube for her. Others saw it and asked questions. It snowballed and he became a teacher.

From start-up in 2006, there are now 31 employees. The site claims 3.6 million unique page views a month and says two million exercises are being completed by students every day.

Khan's lucky.

There are similar video tutorials out there. Some of their producers have the same remorseless work ethic, sponge-like retention and good-guy enthusiasm Khan has.

But Khan caught the eye of someone rich and then the attention of Bill Gates. Money flowed and he took his place in a possible future history of education.

Like the lessons, the concept the academy and its backers support is easy to understand. The school day will be flipped: students will learn the ideas at home from Khan or a similar agent, then go to school to do the practical problems under the electronic gaze of a teacher - the opposite of what is supposed to happen now. Teachers will have real-time information on the progress of every student on every problem and be poised to intervene with extra help exactly when and where necessary.

Merryn is in year 10. She's used this before, not in an organised way, more as a recap of stuff she's done at school. This one's about the concept of X and Y intercepts.

Khan juggles his way through it. He never appears on camera - all you get is a screen that he writes things on with different coloured markers, and his voice. His style is of a new enthusiast, going back and changing colours and appearing to work through it on the fly. He makes the vast majority of the site's lessons himself, after teaching himself the concept to be explained.

He says the videos are done all in one take on his desktop, rather than in bits or with edited material. If he doesn't like how a segment's coming together, he'll wipe it and start again. It makes for a freshness and immediacy lacking from set lectures delivered for the hundredth time.

Merryn's not wildly enthusiastic in return. "I would have to watch it a couple of times to understand it completely, but it gives me a basic understanding of what to do," she says.

But after one run through, she believes she would be ready to build on the basic knowledge in a classroom. The distance of the tutor is a concern for her, though. "School is probably better, because if you have questions, you can ask," she says. She tries out matrices, a subject she has never done before, to see how the system copes with total novelty. Pace seems to be an issue in teaching, a horribly difficult thing to judge with a class full of individuals.

"The problems come when people don't understand and the teacher just keeps on going," says Merryn, "or there are complex terms that you just don't know. Or they go too fast and teach you too much and you don't remember it by the next day."

Khan's got the opposite problem here. His laborious squiggly text is almost too slow for her, going off-track into a fairly irrelevant side-issue. And suddenly there's a mistake. A number is wrongly labelled as a positive rather than a negative. Merryn spots it just before a little pop-up appears on the screen admitting to the howler and correcting it.

Khan's been criticised for his mistakes before, more on the way he teaches rather than straight-out errors like this one. There is even a cash prize on offer for the best critique of a Khan video. Despite the glitch this one's a hit with Merryn.

"I didn't know that before and now I understand it."

She'd still like to have a human teacher around in case she got lost.

Brother Niall's in year 12 and hasn't used the academy before. He reckons he trips up on the in-depth stuff sometimes and claims to be really bad at geometry. We pile into Pythagorean theory and how it applies to working out part of the area of a parallelogram quilt. It seems to be making sense.

"Yeah, it does," he says. "These are the ones that you understand when the teacher tells it to you, but when it goes a bit more in-depth, then you struggle sometimes."

He says that doing rather than just watching a lecture is a better way of learning for him and the practical problems on the academy pages are just the ticket. The lack of time pressure is different from being at school, too.

"In class, I'm pretty bad sometimes with not asking questions. I don't want to be a pain to the teacher. They are on a schedule sometimes and when you have got 30 people in some classrooms, it must be difficult to keep everyone up to date."

Khan is muddling his way expertly through an equation, crossing out things and swapping stuff around.

"The teachers often just give you the answer without the working for it," says Niall.

Both Merryn and Niall like the repetition and repeatability of the videos. Niall says it would be preferable to the weeks of textbook revision he has to put up with at some points in the school year, a situation he characterises as "crusty". But at the end of the show, both say they'd still rather have a teacher in the room when learning the basics.

Chris Clay is a teacher, the head of science at Botany Downs Secondary College.

Last year, he was flown to Washington for a presentation after he picked up a globally judged teaching award in the category of Extending Teaching Beyond the Classroom. He publishes science lessons online and administers a forum for kids to get together and discuss them, in addition to hosting Chrisclay.org for educators.

"Whenever I do a normal chalk and talk in the classroom, it's lost in the ether. If you're listening, you get it; if not, you don't."

If students don't get it, or forget it, the video gives them the opportunity to wind the clock back. But he is adamant that teachers cannot be replaced with a video.

"The main thrust for me is to take that teacher-focused part of the lesson away from the normal lesson time, allow the student to do that at a time when they are on their own and can focus on it. So when you've got the student in the classroom, you are working on something that is more student-focused."

He says the resources available from both Khan and himself should only be a small part of what happens.

"I think that is something that people need to keep in mind. There is a bit of a drive towards seeing this ‘flipping the classroom' as a panacea. It is really just a small part of freeing up the time for real professional teachers to get their hands dirty and do the real job in the classroom."

He believes putting a computer in front of students will only work when they are learning a closed skill - like maths - and not for many other things, including his own specialist subject of biology.

"There, you are dealing with a much more open piece of learning. Collaboration is really, really important for all learners. Khan's Academy or my videos really just provide something that is a talking point for students to collaborate around."

His online forum, where students from around the country post questions and help each other, is growing in importance. The forums also pass on information about how people are doing in more than the obvious ways.

"If a student is not asking enough questions, then they are not being critical enough of their own knowledge and they are not identifying what they need to do to succeed. They are expecting that to be spoon-fed to them."

The last part feeds into what Derek Muller wrote in his doctorate about all this back in 2008. His findings were disturbing. He experimented with different ways of teaching physics on video. One type was a straight lecture, a la Khan.

"That was a shocker for me," says Muller. Straight exposition (a traditional lecture) for novices on Newton's Laws was completely ineffective - on average, nothing was gained. Except for confidence. In other words, many students were worse off, believing they had learned something when they had not. The problem is that new science students bring with them heads full of misconceptions and think they already understand what they are seeing. Their ideas may be intuitive and work well in the everyday world, but don't translate into scientific principles. For instance, a ball thrown in the air is going up, but in pure scientific terms, has only one relevant type of force acting on it after it leaves the hand - the constant downward push of gravity.

Students would watch the straight video lecture with their incorrect knowledge not directly challenged (typically that the ball is still subject to some upward force) and emerge with it intact, believing it had been confirmed. Muller found out how to fix this. If common misconceptions are included in the video and their wrongness explained, people understand the truth far better.

But it's hard work.

The students rated his videos with a straight lecture containing facts - from which they learned nothing - as easy to understand and clear. The lectures where misconceptions were explored were not easy and not clear, but they learned from them and post-video test scores nearly doubled. Muller has his own video learning channel, Veritasium, on YouTube, using his techniques and he is a featured speaker at educational forums.

"I found that something in a one-way presentation needs to alert the viewer that they need to be investing more effort - in other words, paying more attention or focusing more. You need to increase the [cognitive] load by representing their misconceptions and using that as a starting point."

Giving them a wake-up call in plain language is a thing the easy-going Khan lectures lack. "Khan is doing things off the top of his head and from time to time does include misconceptions. But it's not relying on any kind of educational research or pedagogy besides what Khan thinks is good. There will be successes and failures, which is fine for what it is, and what happens when you base things on your intuition."

Muller refuses to condemn Khan's videos wholesale.

"My results are for novices. For advanced learners, who maybe had just had a summer off, I saw significant gains with the exposition."

For revision, the Khan Academy is fine. But, in its current incarnation, it isn't the last word.

"I think he is a great teacher and his tools have a place as long as it isn't the only thing people are using for their instruction," says Muller.

- © Fairfax NZ News

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