Turning the Classroom Upside Down

Posted by jcmaziquemd on April 9, 2011

Turning the Classroom Upside Down

Why not have lectures at home and ‘homework’ at school—and let students learn at their own pace?


[KHAN]Robyn Twomey/Corbis Outline

SALMAN KHAN, above, started out posting videos for his cousins on YouTube. Now his academy has 2,200 videos online.

We all know the standard drill for a math class. The teacher delivers lectures on a new concept, students do some homework problems, and after a few weeks they take an exam. Some do well, some do poorly, and then it’s on to the next topic.

Pop Quiz!

Some math exercises from the Khan Academy website. Click here for the answers.

1. Solve for x: -5x = -1

2. Which of these numbers is prime? a. 56 b. 91 c. 17 d. 51 e. 26

3. What is the least common multiple of 20 and 36?

4. If -5x-y-5z = 1

Then what is -5y-25x-25z ?

5. Evaluate the following expression when x = -1.

6. Alice traveled by bus at an average speed of 20 miles per hour. Then she traveled by moped at an average speed of 44 miles per hour. In total, she traveled 216 miles for 6 hours. How many minutes did Alice travel by moped? (Round to the nearest minute.)

7. Gulnar has an average score of 87 after 6 tests. What does Gulnar need to get on the next test to finish with an average of 78 on all 7 tests?

8. In 15 years, Gulnar will be 6 times as old as she is today. How old is Gulnar today?

The problem with this model of instruction is that it leaves behind large gaps in understanding. For A students, it might be a 5% gap, for C students a 30% gap. But all of them end up with a Swiss-cheese education—full of holes. Little wonder that, when they reach algebra and calculus, they often struggle. It’s like being trained to juggle oranges half-competently and then being expected to juggle knives.

But it doesn’t have to be this way. In 2008, I started a non-profit organization called the Khan Academy to deliver free online education. As it turns out, our tools have given students and teachers the power to "flip" the traditional classroom: Students can hear lectures at home and spend their time at school doing "homework"—that is, working on problems. It allows them to advance at their own pace, gaining real mastery, and it lets teachers spend more time giving one-to-one instruction.


At the Khan Academy, in Mountain View, Calif., learning is flipped. Lectures take place at home with videos over the Internet. And "homework" is done at school, where teachers intervene. Salman Khan talks with Kelsey Hubbard about his theory of education.

It all started with my cousin Nadia. Back in 2004, I was working as a hedge-fund analyst in Boston when my relatives from New Orleans visited for the Fourth of July. Waiting for the fireworks to begin over the Charles River, I kept everyone occupied with a battery of brain teasers. Nadia’s answers were particularly impressive. She was only 12, but she engaged the problems with more energy and creativity than many engineers and scientists twice her age.

That weekend, touring the campus of MIT (where I had studied math a few years before), I hinted to Nadia’s mother that this might be a good college for Nadia. She confided that, despite being a straight-A student, Nadia had done badly on a placement exam and was being tracked into a slower 7th-grade math class. I offered to help.

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In our first months of working together remotely, I spent 30 minutes to an hour with Nadia each day on the phone, using Yahoo Doodle as a shared whiteboard. Before long I was also working with her younger brothers and an informal cohort of students around the country. It became clear that the only way for me to meet this growing demand was to put some tutorials on YouTube.

During our live sessions, my cousins had only heard my voice and seen my writing, so for the videos I just used free screen-capture software to reproduce that experience. I wrote in pastel colors on a black background and kept to the YouTube time limit of 10 minutes per video. My cousins soon informed me that they liked me better on YouTube than in person!

I was surprised that they preferred an automated version of me, but look at it from their point of view. They could now pause and repeat the lectures without worrying that they were wasting my time. They could review topics from previous sessions without feeling embarrassed, and they could tackle new topics without the stress of someone watching over or judging them.

Salman Khan

An image from one of Mr. Khan’s lessons.


I soon discovered that people all over the world were watching my YouTube videos. More important, teachers were using them to change the basic rhythm of their classrooms. They asked their students to watch the videos at home and then used class time for actual problem-solving. Instead of 30 students listening passively to a one-size-fits-all lecture, they were learning at their own speed. Some could focus on filling in gaps in their arithmetic while others were able to jump ahead to trigonometry—and it all took place in the same classroom. It is often said that technology makes modern life less personal, but in this case, it has allowed teachers to take a big step toward humanizing their instruction.

Today, with the help of some generous donors and a die-hard user base of students and parents around the world, Khan Academy is now a team of six people building software and content, and we have more than 2,200 videos, covering everything from arithmetic and calculus to biology and physics. Surreal as it seems to me, the simple videos that I started making for my cousins have now been viewed almost 45 million times and are being translated into more than 10 languages.

Last fall, we began a pilot program with the public schools in Los Altos, Calif., in the heart of Silicon Valley. The initial results are very promising. In order to help teachers customize their instruction, we created a dashboard of robust data for them to follow, linked to their students’ online exercises. Students don’t move on to more advanced concepts until they have mastered basic ones. Those who get "stuck" promptly receive help, often from peers who are already proficient in a subject. The overall effect has been to create a more collaborative classroom culture.


1. 1/5; 2. c; 3. 180; 4. 5; 5. 12; 6. 240 minutes; 7.24; 8. 3

Still more encouraging, our data show that when students work at their own pace, the need for traditional tracking and labeling goes away. Given the time and personal instruction needed to master core topics, supposedly "slower" students are often able to speed ahead. Within weeks, they look "advanced."

To us, the conclusion is obvious: Students simply do better when schools show respect for their natural curiosity and intelligence and give them a chance to achieve an intuitive understanding of fundamental concepts. It turns out that, in order to juggle knives, it helps if you’ve first learned to juggle oranges with ease.

—Mr. Khan is the founder of the Khan Academy (www.khanacademy.org).

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