In 2004, hedge fund analyst Salman Khan began tutoring his 12-year-old cousin, Nadia, in some basic math concepts. Since he lived in Boston and she in New Orleans, they spoke by telephone, and he used Yahoo! Doodle to work through specific problems.

As other family members requested his services, Khan began to post simple video lectures on YouTube. Khan realized he was on to something when strangers began leaving comments, thanking him for explaining things like systems of equations and geometry in a way that finally made sense.

In 2009, Khan quit his lucrative job to put all his efforts into Khan Academy. He founded the nonprofit with a lofty goal in mind: to provide a free, world-class education for anyone, anywhere.

Students from 234 countries and territories have logged on to Khan’s site to watch any number of his 3,400 video lectures on topics in math, science, computer science, economics and history. Teachers in some 15,000 classrooms now incorporate his lessons and software into their instruction.

In his new book The One World Schoolhouse, Khan totally reimagines education. He diagnoses the problems with our century-old model for education and envisions schools that better prepare students for today’s world.

Secretary Wayne Clough will interview Khan tomorrow about his refreshing ideas for education reform as part of a Smithsonian Associates event at the National Museum of the American Indian.

What does the school of the future look like, as you see it?

We can define it by what it is, or maybe by what it is not. You won’t have bells ringing every 50 minutes. You won’t have a state-mandated curriculum where all the students and all the teachers are all going at the same pace. Students are not going to be in these rooms where all the desks are pointed at the chalkboard and there is somebody lecturing at them.

What I imagine is much more open, collaborative workspaces. I imagine the students come in, and they work with their mentors. Their mentors will be both students, possibly older students or students who have shown maturity, and the master teachers. They will set goals. Based on those goals that they are trying to achieve, they have a rough allocation of how they might want to be spending their time. One day a student might want to go deep on trigonometry. Then, he or she might spend two weeks researching some problem in biology or writing a short story.

Both teachers and student mentors will be able to keep track and say, “Look, it’s great that you’ve spent the last month working on your novel. We think that is a really important life experience. But we think you need to invest a little bit more time in your core math skills.

Students will build a portfolio of their creative works; it will serve as their academic credentials to show, “Look, I really do know geometry, or I really do have a basic understanding of American History.” It will also include an evaluation as a peer mentor. How good was the student at helping other people? At explaining things? At first it sounds like a very pie-in-the-sky, touchy-feely thing, but this is actually what employers care about.

So you don’t believe in letter grades?

For me, letter grades are a very superficial thing. An “A” can make it look like there was rigor when there wasn’t any. What does an “A” mean? It depends on how hard or rigorous the assessments were. It gives you very little information. They allow us to assess people, realize they have gaps in their knowledge and then just push them forward, guaranteeing that at some point they are going to get frustrated and kind of fall off the bus.

You call for the end of summer vacation. Why?

We want students to learn! Right now, students are spending nine months stressed, going through drills, memorizing things before an exam and then forgetting it. Then, they go to summer vacation. Some of the most affluent or motivated kids might be able to pull off having a very creative summer vacation, but most don’t. For most, it is just kind of lost time.

When people say, “Summer vacation, those are my best memories. That is when I actually got to do creative things. That is when we actually got to travel,” I say, yeah, exactly, that is what the whole year should be like. Make school year-round, but also make it much more like a creative summer camp.

What is the biggest obstacle to reaching this school of the future?

It is very hard to de-program the model that we grew up in. To some degree, our notion of school is adults scheduling every hour of a child’s time. You have to de-program that in the leaders of the first one or two or ten schools. But, I think all of this can be done over the next five or ten years.

As you say, we take the traditional school model for granted—teachers lecturing for 40-90 minute class periods devoted to separate subjects and then assigning homework. But, how and when did this take root?

The Prussians came up with it. To their credit, they said, “We want to have everyone educated.” How do we get everyone educated? Well, it was the late 1700s, early 1800s. Assembly line factories were producing things fairly inexpensively and in reasonable quality, so the Prussians said let’s see if we can industrial revolutionize teaching.

Before that, you would have the master teacher work with one student or small group of students at a time. They said, “Well, how do we get that to scale? We put these students in age-based cohorts and move them at the same pace.”

In the mid-1800s, the model got brought over to the U.S., with a very egalitarian motive: Let’s have universal public education and do it reasonably cost effectively. The Land Grant universities come about, so university was much more accessible. We start to have textbooks, but we need to standardize what a high school diploma means, so we understand what students are coming to the universities with or are entering the job market with. That is when you had the Committee of Ten say there will be primary school and secondary school. In secondary school, you will learn algebra and then geometry and then trigonometry. You will learn physics near the end, and you will learn earth science near the beginning.

As someone with three degrees from MIT and an MBA from Harvard, you have had success within this system. But, what, in your mind, are its biggest flaws?

The biggest flaw is the dearth of time for creativity. This is probably hitting the affluent more than anyone else, strangely enough. I actually felt like I was lucky growing up. My mom was a single mom. We didn’t have a lot of money, so I didn’t take any classes. I was what they used to call in the ‘80s a “latchkey kid.” I would come home, and my mom wouldn’t come home for a couple of hours. I essentially had the afternoons at my disposal.

Frankly, most of my peers, their kids are completely booked. From morning until nighttime they are either in school or some type of soccer or piano practice or they are doing homework, and then they go to sleep. There is no breathing room at all for a child of any age to say, let me create something. Let me invent a new game. Let me just play.

You have created a library of over 3,000 videos explaining everything from basic trigonometry to the Law of Thermodynamics to the Cuban Missile Crisis and Obamacare. What is the key to an effective video lecture—one that will get through to students?

The tone should be respectful. Respectful means not talking down and not talking above. You have to view the viewer as someone who is just like you, someone who is smart and capable of knowing the information, but who just doesn’t know it right now.

Make sure that you cover all of the details. Make sure you cover all the whys. Make sure you draw all the connections. These are things I never had the luxury to do in my schooling. I never had the time or luxury to think, why do I carry a “1” when I add? The class was moving on. But now I do have time. This is my job. My value-add is to think about those and to try to give a little bit more of that intuition and texture. If it can be a little bit quirky and funny, I think it connects with people even more.

How are teachers incorporating your videos and software into their instruction?

The simplest way is teachers writing on the top of the chalkboard on Day 1, if you are ever stuck on anything in this classroom, this site called Khan Academy might help you. There are a lot of supplemental learners—people who are taking a chemistry class at their high school or university and using Khan Academy as a tutor.

The next level is flipping the classroom. When Khan Academy was just ramping up and I was still doing this as a hobby, I would get these emails from teachers saying that they didn’t have to give these lectures anymore. They could say, “We are covering systems of equations or we are covering meiosis. Here is a Khan Academy video that you might want to watch before our next class.” Then, they could use class time to actually do problem solving with students and work directly with them. They essentially had “flipped” the classroom. What used to be homework—the problem solving—was now in the classroom; what used to be class work—the lectures—was now happening at home.

The deepest [application] is the classrooms where the students really are all learning at their own pace. Teachers have the students working on the Khan Academy exercises and videos at their own time and pace, and then the teachers get data and can intervene when appropriate. The class time is being used for interventions with or between students or open-ended projects.

Really, we want to see who is pushing the envelope the most, see if it is working and then why it is working, and then try to share those practices with other teachers.

How does this new type of school level the playing field for all students?

Historically, whenever someone has talked about solutions for the underserved, they would always think about cheap approximations to what the rich had. But any child who has access to the Khan Academy site now has access to the same resources that Bill Gates’ kids are using.

The good thing is, especially in the developed world, computers and broadband are already fairly common. Even in the developing world, things are getting cheap enough that they are starting to become practical, especially on mobile platforms. At minimum, students now have access to this interactive tutoring. Ideally, they will also be able to supercharge what is happening in their classrooms. They would be able to have access to differentiated instruction. This is what kings’ children had. Not even Bill Gates’ children have this personalized attention in their schools. We are saying there is now a way for teachers to give personalized attention to students in a scalable way.

This interview series focuses on big thinkers. Without knowing whom I will interview next, only that he or she will be a big thinker in their field, what question do you have for my next interview subject?

What surprising change in society is around the corner that no one sees coming?

From my last interviewee, Steven Johnson, author of Future Perfect, which claims that the key to progress is peer networks, as opposed to top-down, hierarchical structures: When you look back on all your big thoughts, what is the biggest thing that you missed? What was the biggest hole in your thinking?

When I started this, Wikipedia and these things already existed. I was a 100 percent believer in the peer networks, and I still am. But I assumed for something like this dream of Khan Academy, we were going to have to get millions of people, or at least thousands or hundreds of people, making content. The shocking thing for me was how scalable even one person could be in this domain.