美国国家公共电台 NPR Sal Khan: Can Technology Help Create A Global Classroom?（在线收听）

GUY RAZ, HOST:

So here's what a chemistry class at the Khan Lab School in Los Altos, Calif., sounds like.

UNIDENTIFIED CHILDREN: (Singing) Hydrogen and helium and lithium, beryllium, boron, carbon everywhere. Nitrogen all through the air.

RAZ: Don't you just kind of want to be in that class?

UNIDENTIFIED CHILD #1: I spend at least half an hour every day coding. So I do JavaScript. And now I'm just starting to learn Python.

RAZ: JavaScript and Python, pretty crazy, right? Anyway, the Lab School opened up in 2014 as, well, an education laboratory, a kind of testing ground...

UNIDENTIFIED CHILD #2: Our hazmat suit is built for Europa.

RAZ: ...Where kids from different age groups collaborate.

UNIDENTIFIED CHILD #2: The problems are that it's very, very cold there, plus there's deadly radiation.

RAZ: And at the Khan Lab School, classes go year-round and there are no grade levels.

SALMAN KHAN: You know, they come in, there's a group time where, you know, you have kids as young as 5, as old as 14, all together in a room. You know, they really feel like cousins. A lot of...

RAZ: This is the school's founder, Sal Khan.

KHAN: They'll have their morning meeting. Then they go into core skills time. There's a lot of peer-to-peer interaction going on in that period. But once you get to lunch and the whole afternoon, it's mainly project-based learning, students working in kind of this collaborative, cross-age environment.

RAZ: And at the heart of Sal Khan's approach, flipping the classroom so that students watch online lectures at home but spend a lot more time working with teachers and other students in class.

KHAN: It makes the classroom take advantage of the human beings that are there. It makes it an active process. It allows the teacher to see in real time where the students actually are. And the idea of getting the information, well, it's better when it's on your own time and pace and you can pause and repeat and watch exactly what you need.

RAZ: And this whole idea of flipping the classroom, it's something Sal kind of stumbled upon more than a decade ago when he started to post these free educational videos online, which he called Khan Academy.

KHAN: So in a traditional lecture model, I show up, I'm like, all right, I'm sitting here. And it just happens to you. And some of it might stick. While on demand video, when I click on a video, I'm only going to click - it's kind of like asking a question. Hey, I'm still confused about this. Give me another five-minute example or explain the concept a little bit better.

And so when you are pulling information, you're naturally going to be more open to it.

RAZ: Khan Academy began sort of by accident in 2004. At the time, Sal was working at a hedge fund and his 12-year-old cousin came to visit. And she was dispirited because she'd been placed in a slower math class.

KHAN: I asked her about it. Turns out, she had trouble with unit conversion.

RAZ: You know, changing feet to meters or gallons to liters.

KHAN: I offered to tutor her, convinced that she could understand unit conversion. And so we started working together over the phone.

RAZ: And eventually, she got it.

KHAN: And then I called up her school, I say, hey, you know, I think Nadia (ph) should retake that placement exam from last year. They said, who are you? (Laughter) I said, I'm her cousin. And they let her. And that same Nadia that two months ago was being tagged and tracked as a remedial math student was now placed into the advanced math class. And then word gets around the family that free tutoring is going on.

RAZ: So one cousin becomes two, then three and then four, five, six, seven, eight...

KHAN: Once it was 10 or 15 cousins, the scheduling logistics got a little bit more difficult.

RAZ: Sal would organize conference calls. And then he would email pictures of math problems back and forth. And eventually, someone suggested, hey, why don't you just post your lessons on YouTube?

KHAN: I actually wasn't that familiar with it at the time. And I said, no, no, that doesn't make any sense. YouTube is for cats playing piano.

RAZ: (Laughter).

KHAN: It's not for serious mathematics.

RAZ: But he tried it anyway.

(SOUNDBITE OF YOUTUBE VIDEO)

KHAN: Welcome to the presentation on adding and subtracting fractions. Let's get started.

And I started telling my cousins, hey, I'm making videos on a lot of the common concepts and questions that y'all are asking me about. Why don't you watch them ahead of time and when we get on the phone, we can dig a little bit deeper? And after about a month, I asked for feedback and they famously said they like me better on YouTube than in person.

(SOUNDBITE OF YOUTUBE VIDEO)

KHAN: So this one-fourth right here, let's say it's this one-fourth of the pie, right? And we're going to add it to another one-fourth of the pie.

I think what they were saying is it was very valuable to have it on demand. They didn't have to feel embarrassed. They didn't have to feel like they were wasting my time. And so I kept going. It was public on YouTube, started to become clear that people who weren't my cousins were watching. That just kept growing.

(SOUNDBITE OF TED TALK)

KHAN: Even at this point, you know, I said, OK, maybe it's a good supplement. It's good for motivated students. It's good for maybe homeschoolers. But I didn't think it would be something that would somehow penetrate the classroom.

RAZ: Sal picks up the story from the TED stage.

(SOUNDBITE OF TED TALK)

KHAN: But then I started getting letters from teachers. And the teachers would write saying we've used your videos to flip the classroom. You've given the lectures. So now what I do is I assign the lectures for homework. And what used to be homework, I now have the students doing in the classroom. And I want to pause here for a second because this is the unintuitive thing when you talk about technology in the classroom.

They took a fundamentally dehumanizing experience, a bunch of - 30 kids with their fingers on their lips not allowed to interact with each other, a teacher, no matter how good, has to give this kind of one-size-fits-all lecture to 30 students - you know, blank faces, slightly antagonistic. And now it's a human experience. Now they're actually interacting with each other.

RAZ: So how does Khan Academy teach, let's say, algebra to a seventh grader differently than that seventh grader would learn it in a classroom in middle school?

KHAN: Well, one, we want to put practice first and practice at your level of development. So in a traditional school, it might be October. Hey, we're all going to be doing exponents in seventh grade. What we would recommend is let students start at the beginning and then let them keep practicing at their own time and pace. And then the teacher can get information on where all their students are and intervene accordingly.

Say, hey, those students are getting exponents just fine, let them move on to logarithms, while these students are actually, not even exponents, some of these students are having trouble with their multiplication tables. Let's make sure they have that foundation well because if they don't learn that, exponents are going to be near impossible.

And so it allows the teacher to become more of a master conductor of an orchestra. And, you know, this has to be a little bit louder, this has to be a little bit more quiet. So that's what we generally advocate. In terms of the actual content materials, I think there's a lot of teachers out there, incredible teachers who do a very good job of connecting material, making it make conceptual sense.

I think textbooks do a pretty bad job of that. It tends to fragment the knowledge, make it seem like a series of formulas. And so we're trying to do both of these things - allow classrooms to move to this more personalized, you could say, competency-based world. And at the same time, allow the content to be delivered in a way that is much more natural for students, that feels much more conceptual and also exposes the beauty in things.

RAZ: So could this approach, could flipping the classroom actually revolutionize teaching? In a minute, why Sal Khan believes the answer is yes. Stay with us. I'm Guy Raz, and you're listening to the TED Radio Hour from NPR.

(SOUNDBITE OF MUSIC)

RAZ: It's the TED Radio Hour from NPR. I'm Guy Raz. And on the show today, ideas about rethinking school. And before the break, we were hearing how Sal Khan turned an experiment with online videos into a teaching tool to flip the classroom. In more than 10 years since he launched Khan Academy, millions of people have watched the videos, all free and made available in more than three dozen different languages.

(SOUNDITE OF ARCHIVED RECORDING)

UNIDENTIFIED MAN: (Foreign language spoken).

UNIDENTIFIED WOMAN: (Foreign language spoken).

UNIDENTIFIED MAN: (Foreign language spoken).

(SOUNDBITE OF TED TALK)

KHAN: Imagine what it does to a street kid in Calcutta who has to help his family during the day and that's the reason why he or she can't go to school. Now they can spend two hours a day and remediate or get up to speed and not feel embarrassed about what they do or don't know. Now imagine what happens where, you know, we talked about the peers teaching each other inside of a classroom.

But this is all one system. There's no reason why you can't have that peer-to-peer tutoring beyond that one classroom. Imagine what happens if that student in Calcutta all of a sudden can tutor your son or your son can tutor that kid in Calcutta. And I think what you'll see emerging is this notion of a global one-world classroom. And that's essentially what we're trying to build.

RAZ: Could Khan Academy, I mean, could it replace school for - or does it replace school for lots of children around the world who may not have access to traditional classrooms?

KHAN: In an ideal world, you have a physical school. Obviously, we created a physical school so we think it's very, very important. But the reality is that many students, you know, it could be in under-served areas, it could be in rural areas, impoverished areas, there could be cultural barriers to going to school. You know, we've had some stories of young girls under, you know, controlled by the Taliban, they're using Khan Academy as their outlet.

So, yes, we - ideally, you go to a classroom, and we can help supercharge that classroom. But if you don't have access to a classroom, yes, we want to make it so that you could self-educate and prove what you know to the world and so that you can participate in society.

RAZ: I mean, I guess what you're essentially trying to do is to append an outdated system.

KHAN: Yeah, around the world, we have essentially adopted what could be called a Prussian education system. And it's referring to 18th, 19th century Prussia, one of the first places to industrialize and also one of the first places to rightfully think about universal public education. And - but what they did say - they said, well, we can't give everyone a private tutor like nobility used to get.

If we want to make this economic, well, let's - this is the Industrial Revolution. How do we do anything at scale? Well, we batch things together, we move them down in an assembly line, we apply some processes to it. And so that's the model that throughout the world we have. Students are batched together, initially by age, around middle school, age and perceived ability.

They move forward at a set pace. But now we have technology, we have notions of on demand video. And so the opportunity - it no longer has to be this utopian thought - is let's give students explanations when they need it, if they need it. Let's give them practice when and if they need it. And so our end isn't just to change things for the sake of changing things.

Our end is we want a world where you have access to, you know, a low-cost device, you can access Khan Academy, self-educate yourself and plug in either to the formal academic system or get a job, become part of society.

RAZ: Sal Khan, founder of Khan Academy and the Khan Lab School. You can see all of his talks at ted.com.