Can the Khan Academy flip a classroom?

March 14, 2011 at 11:48 am 14 comments

Salman Khan’s recent TED talk has generated a lot of buzz. (You can check out the video here.)

At one point he mentioned how the Khan Academy videos are being used to “flip” the classroom, and that’s when I got a little worried. I like the idea of flipping the classroom – having students learn concepts via video outside of class and using class time to work on problems, turning the teacher into a mentor or coach. My friend Mike Sullivan has done this with great success at his college. In this environment, there is more time for collaborative learning and one-on-one instruction. I feel that this can really help students to learn and understand mathematics.

My problem with the Khan Academy videos is that they are “how-to” videos, and conceptually barren. I recently watched a video on dividing fractions, and the video began with the problem \frac{3}{5} \div \frac{1}{2} on the screen. He started by saying “Whenever you are dividing any fractions, you just have to remember that dividing by a fraction is the same thing as multiplying by its reciprocal. So this thing is the same thing as three-fifths times … two over one.” This video does not explain why we multiply by the reciprocal when dividing by a fraction, it’s just what we do. There is no development of the topic. I think that students that are told “Do this. Do this. Do this.” will not understand what they are doing, but instead will be able to mimic the video’s work. I don’t think they will retain the knowledge, and we cannot build world-class math students on such a shaky foundation.

Now, don’t get me wrong, I love the Khan Academy videos. But I love them for what they are – how-to videos that students can refer to as they are learning a topic. I send my students to these videos all the time. I love that they are available online for free. I love the story of how he started doing the videos. I especially love how he left his job as a hedge fund analyst to do these videos, there’s something admirable and Escallante-ish in that. I feel badly saying anything negative. It’s just that in their current form they cannot teach students, they can only reinforce what has been already covered in the classroom. They cannot be used to truly teach mathematics.

Am I missing something?

Please leave your opinion as a comment, or you can reach me through the contact page at my web site – I’d especially like to hear from those of you who have experience in flipping the classroom.


I am a math instructor at College of the Sequoias in Visalia, CA. Each Wednesday I post an article related to General Teaching on my blog. If there’s a particular topic you’d like me to address, or if you have a question or a comment, please let me know. You can reach me through the contact page on my website –


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Solving Systems of Linear Equations by Substitution Flipping the Class & Khan, Part 2

14 Comments Add your own

  • 1. John Redden  |  March 14, 2011 at 12:13 pm

    I agree with your assessment of the videos. However, to me the idea of assigning the lecture as homework and exercises as classwork is interesting. Maybe not a complete flip but a mix could be worth a try… with the caveat that the videos were more instructional as you point out.

    • 2. georgewoodbury  |  March 14, 2011 at 2:47 pm

      Thanks John. I’m not sure I got that out there correctly – I like the idea of flipping the classroom. I just don’t think it can be done effectively based on the Khan Academy videos.

  • 3. Will Emeny  |  March 14, 2011 at 1:25 pm

    Hi George,

    A fantastic article and excellent timing! I’m currently setting up a site to help secondary school pupils with their maths using videos but with a strong emphasis on understanding rather than learning methods!

    The site is still very much in it’s early days but the fractions series are looking great:

    I’d be fascinated to know your thoughts!

    • 4. georgewoodbury  |  March 14, 2011 at 3:46 pm

      That’s more like it. I think that students need conceptual understanding, and these videos spend a good amount of time developing concepts. I especially liked the approach for adding fractions with unlike denominators – very intuitive!

  • 5. Jason  |  March 14, 2011 at 4:38 pm

    Hi there. First, I just want to say that I’m a member of the Khan Academy team, and I appreciate you taking the time to think and write about what we’re doing. We learn a lot from our critics.

    That said, I don’t think that your critique is accurate in this case. I am not sure if you actually watched the video all the way to the end, but Sal does in fact give an explanation for WHY this method works (multiplying by reciprocal). He makes a point of doing this in as many videos as possible, and in this case spends nearly half the video explaining the concept. You might not find this explanation clear, but to say that he is merely showing the mechanics of how to do the sample problem is inaccurate.

    Can the videos get better? Absolutely. Can we do more to reinforce this conceptual learning with other types of activities? You bet! Our goal is not simply to teach mechanics and we succeed in that goal much of the time (whether or not it gets all the way through to the student is something we are actively assessing and measuring).

    Regardless of the particulars, I think this kind of discussion and debate is really healthy for education in general, so keep it up! And if you find resources out there that you think are doing a better job (like the mathmaster folks), we’d love to know about ’em.

    • 6. georgewoodbury  |  March 14, 2011 at 6:26 pm

      Hi Jason – Thanks for reading & commenting!
      I did stop watching at the end of the first example, so I will definitely go back and watch it all. It is consistent with the other videos I have watched (jumping right into examples), and I usually watch the first example or two before recommending a video to my students to make sure the approach is consistent with mine. To be fair, I will go back and look at a selection of videos – maybe my experience is a bad sample.
      (EDIT: I would prefer that the development of the concept occur prior to the examples.)
      FWIW – It was hard to write anything bad about Khan Academy, because I appreciate what you have done and I do use them/recommend them to students often. I am just not sure that this tool is sufficient for flipping a classroom. Time will tell.

  • 7. Annmaria  |  March 14, 2011 at 5:32 pm

    Coincidentally, I just watched that TED talk today. I think his videos will work for some students. Maybe they heard the lecture on why in the classroom and just need the how to. I think these are certainly great for students who want a refresher or more explanation of a specific topic. Will they be adequate for all students ? Definitely not.

    Will they allow teachers to lecture less and spend more time with individuals or small groups? Quite possibly. Will they replace lectures completely? I think that’s a bad idea. For one reason, the teacher is THERE and can see where students are confused and give an appropriate explanation on the spot, tailored to those students

    • 8. georgewoodbury  |  March 14, 2011 at 6:16 pm

      Hi Annmaria – That’s where I was going. If the student has already seen the conceptual development of a topic, then “how to” videos are valuable.
      When I think of flipping the classroom in a case where each student is on the same pace, developing concepts in the classroom followed by brief video instruction a la Khan followed by practice with peer or instructor mentoring/coaching/assistance, then I think that definitely can work.
      However, if every student is working at their own pace, it is impossible for me to develop those concepts on a one-on-one basis. I would need another batch of videos that developed the concepts before students viewed examples. By the way, i feel that this is the direction that many progressive educators are heading. (I have a comment from a Khan team member that I will share shortly, and he states that the “Why” is explained in most videos. I suppose that I would like to see that up front, and to be fair to the Khan team I will research this in greater depth. If true, perhaps the Khan videos would support this classroom style.)
      I feel that I do a pretty good job getting 40 students in my classroom to understand a topic. If I were able to spend more one-on-one time with my students, I’m sure I could do an even better job. If my students were able to spend more time working with each other, helping each other, and learning from each other, I feel that understanding would increase too. So, the approach intrigues me, even if I am not sure that this is the right tool.

  • 9. Milena  |  March 15, 2011 at 12:16 am

    I am really enjoying this discussion since I have been working on flipping my classroom using the Khan Academy among other sources. There are a couple of points that I had to clarify for myself before that. Let’s use your example with the fractions. I agree that the conceptual development needs to come before the skill is mastered. That’s why, what I would do is assign an exploration on division of fractions in my classroom ( I know I will have the time, since I don’t have to teach the skill.) Once they have developed the intuitive understanding of the concept, they can work at home on mastering the actual skill. Then apply it in class on project work that is again working towards the concept. In short, I find the Khan Academy videos and exercises useful to master a skill and free time in my classroom for the conceptual work.

    • 10. georgewoodbury  |  March 15, 2011 at 5:56 am

      Thanks for the comment Milena.
      Your comment is very helpful in framing the issue. I don’t see how one could flip their class without your approach of concept development first. The teacher IS important, not just for mentoring/coaching students, but for helping students to understand a concept before jumping in and getting their hands dirty.
      I’m still not seeing how a classroom could be flipped in such a way that students could work at their own pace, where each student is working on a different topic, using these videos. I don’t think that these videos (even though there is more conceptual development than I originally saw) provide sufficient conceptual development. I suppose you would have to prepare your own materials/worksheets to introduce students to a concept before they start to work. At that point I can see the Khan videos as one of many tools that would be helpful for students to use as they pursue mastery.
      By the way – what level do you teach?

  • 11. Reva Narasimhan  |  March 15, 2011 at 6:27 am

    I agree with you that many of the math videos out there are basic “how to” types. On YouTube, even the calculus videos that get a lot of views are basically “how to”s.

    How can we teach the concepts? Web sites such as or the National Library of Virtual Manipulatives or Wolfram Demonstrations have a lot of materials that can motivate the concepts. I use these in my classroom for prospective teachers. I can see that one could make concept videos using Jing or some such software with these demos and give an audio narration.

    • 12. georgewoodbury  |  March 15, 2011 at 8:31 am

      Thanks for the comment Reva. Great suggestions. I just checked out your blog – W|A widgets are on my to do list!

  • 13. J Martens  |  April 6, 2011 at 9:12 pm

    You might find this post interesting — takes the critique of Khan Academy a bit further.

    • 14. georgewoodbury  |  April 7, 2011 at 5:59 am

      Thanks for sharing – I caught a few of those. It’s a four part series worth checking out, everybody.


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