Wednesday, March 23, 2011

The Khan Academy -- Virtual Cliffs Notes for Math & Physics (& More!)

Have you ever been stumped by the nuances of your physics, statistics or calculus books? Maybe having a better understanding of some of the basics that never quite sunk in would help.

[Joshua A. Dijksman gave a talk earlier this week about the Khan Academy at the 2011 APS March Meeting.]

Earlier in the week, Joshua A. Dijksman gave a talk about the Khan Academy -- a website that offers a "free world-class education for anyone anywhere," according to the site. The Academy's most prominent feature is its video library consisting of over 2,100 educational videos.

Like a sort of online collection of Cliffs Notes for hard-to-grasp subjects, the video library includes videos that are about 10 minutes long each covering about 40 subjects including physics, developmental math, calculus, statistics, differential equations and many more. During each video, a narrator simultaneously explains concepts while drawing pictures or equations on a computer sketch pad.

The videos
are educational, so they can be difficult to swallow, but if you've ever had a tough time getting a concept down pat, they just might do the trick. It's worth a try. Here's a sample video on fluids:


[A sample educational video from the Khan Academy.]

In addition to the video library, the website offers math practice exercises that can be done online by students who can keep track of their own progress. Teachers can monitor the students' progress online as well.

According to Dijksman's presentation blurb, the Academy's goal is "to allow educators to improve their teaching, but above all to bring simple, rewarding and enjoyable education to the minds of many young students."

3 comments:

  1. The Khan Academy also has all the videos on its own Youtube channel - although I find it easier to navigate the various topics on their own website.
    But what stands out if yo watch his videos on youtube are the comments people leave.
    Things like "wow, you explain this so much better than my teacher at school" or "thanks to you I finally understand what I should have learnt years ago in class" are typical.
    Compared to some commercial, paid-for offerings of math instruction (sorry, have not reviewed any physics), I have found Sal Khan's videos at least on par, if not better.

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  2. I do not know about other subjects but I didn't find the Physics lectures upto the mark.

    http://www.khanacademy.org/v/capacitance?p=Physics

    In the above lecture Mr. Khan writes
    E = 2k pie sigma. The thing is he writes an arrow above E (which I can't write here in print) which means he is taking E as a vector. But there is no vector on the right hand side of the equation. In other words this equation implies that a vector quantity is equal to a non vector quantity. That's obviously wrong.

    http://www.khanacademy.org/v/introduction-to-newton-s-law-of-gravitation?p=Physics

    Then in this video lecture he says that the gravitational force of attraction between any two objects is to be calculated by taking the distance between the center of masses of the objects in question. Now this method works sometimes (as has worked in his video)but generally speaking its wrong. One can only take the entire mass of an object at its center of mass when he is solving a physical quantity which is a linear function of distance. The rigorous method is to use integral calculus. As a matter of fact Newton invented the integral calculus because he wanted to prove that if you are outside the earth then you may take the entire mass of the earth at its geometric center and then apply the force law and you will get correct results.

    Though I admire Mr. Khan's website for providing free education world wide but such errors are bound to happen if one is teaching so many subjects. I think one should only concentrate on the field in which he has a good mastery.

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  3. khan sb kuch samaj nai aa rai sorry yar.............

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